• TABLE OF CONTENTS
HIDE
 Title Page
 Table of Contents
 Preface
 Comments of the vice-president...
 Comments of the dean for exten...
 Comments of the dean for resea...
 Pest management decisions in no-tillage...
 Minimum tillage: One county agent's...
 Breeding small grains: Minimum...
 Conservation of energy in no-tillage...
 Double cropping soybeans succeeding...
 Weed control programs for no-tillage...
 Deeper rooting in minimum tillage...
 Fuel consumption and power requirements...
 Herbicide tolerance and wild radish...
 Weed control for no-tillage soybeans...
 Subsoiling and minimum tillage...
 Comparisons of energy requirements...
 Are no-tillage multicropping production...
 Alternative tillage in Jefferson...
 Alternative tillage demonstration...
 Establishment of legumes in bahia...
 Conservation tillage systems in...
 Pest insects as affected by tillage...
 No-tillage in North Carolina (W....
 The influence of minimum tillage...
 Seeding and reseeding of cool-season...
 Subsoiling: Minimum tillage and...
 Minimum tillage of corn in perennial...
 No-tillage versus conventional...
 No-tillage in Florida from a farmers...
 Postemergence directed spray equipment...
 Soil and water conservation through...
 Soil fertility and its relationship...
 Reducing energy inputs into no-tillage...
 Effect of plant population on yield,...






Group Title: Proceedings of the Third Annual No-Tillage Systems Conference : theme, energy relationships in minimum tillage systems
Title: Proceedings of the Third Annual No-Tillage Systems Conference
CITATION PAGE IMAGE ZOOMABLE PAGE TEXT
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00054801/00001
 Material Information
Title: Proceedings of the Third Annual No-Tillage Systems Conference theme, energy relationships in minimun tillage systems
Physical Description: ix, 202 p. : ill. ; 28 cm.
Language: English
Creator: Gallaher, Raymond N
University of Florida -- Institute of Food and Agricultural Sciences
Conference: Southeastern No-Tillage Systems Conference, 1980
Publisher: The Institute
Place of Publication: Gainesville Fla
Publication Date: <1980?>
 Subjects
Subject: Conservation tillage -- Congresses   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
conference publication   ( marcgt )
 Notes
Bibliography: Includes bibliographical references.
Statement of Responsibility: sponsored by Agronomy Department, Institute of Food and Agricultural Sciences, University of Florida ; editor and coordinator, Raymond N. Gallaher.
General Note: Cover title.
General Note: "June 19, 1980."
Funding: Electronic resources created as part of a prototype UF Institutional Repository and Faculty Papers project by the University of Florida.
 Record Information
Bibliographic ID: UF00054801
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved, Board of Trustees of the University of Florida
Resource Identifier: aleph - 002536937
oclc - 23602316
notis - AMQ2895

Table of Contents
    Title Page
        Page i
        Page ii
    Table of Contents
        Page iii
        Page iv
        Page v
    Preface
        Page vi
        Page vii
    Comments of the vice-president of the institute of food and agricultural sciences
        Page viii
    Comments of the dean for extension
        Page ix
    Comments of the dean for research
        Page x
    Pest management decisions in no-tillage agriculture (J. N. All)
        Page 1
        Page 2
        Page 3
        Page 4
        Page 5
        Page 6
    Minimum tillage: One county agent's view point (J. A. Baldwin)
        Page 7
        Page 8
    Breeding small grains: Minimum tillage and energy implications (R. D. Barnett, P. L. Pfahler, and H. H. Luke)
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
    Conservation of energy in no-tillage systems by management of nitrogen (R. L. Blevins, W. W. Frye, and M. J. Bitzer)
        Page 14
        Page 15
        Page 16
        Page 17
        Page 18
        Page 19
        Page 20
    Double cropping soybeans succeeding soybeans in Florida (K. J. Boote)
        Page 21
        Page 22
        Page 23
        Page 24
        Page 25
        Page 26
        Page 27
        Page 28
        Page 29
    Weed control programs for no-tillage soybeans (B. J. Brecke)
        Page 30
        Page 31
        Page 32
    Deeper rooting in minimum tillage to conserve energy (R. B. Campbell)
        Page 33
        Page 34
        Page 35
        Page 36
    Fuel consumption and power requirements for tillage operations (R. P. Chromwell, J. M. Stanley, R. N. Gallaher, and D. L. Wright)
        Page 37
        Page 38
        Page 39
        Page 40
        Page 41
    Herbicide tolerance and wild radish control in lupine and vetch (G. R. England, W. L. Currey, and R. N. Gallaher)
        Page 42
        Page 43
        Page 44
        Page 45
        Page 46
        Page 47
        Page 48
    Weed control for no-tillage soybeans in rye straw (R. N. Gallaher and W. L. Currey)
        Page 49
        Page 50
        Page 51
        Page 52
        Page 53
    Subsoiling and minimum tillage of corn on Florida flatwood soil (R. N. Gallaher and W. R. Ocumpaugh)
        Page 54
        Page 55
        Page 56
        Page 57
        Page 58
        Page 59
        Page 60
    Comparisons of energy requirements for weed control in conventional and no-tillage soybeans (J. M. Goette, W. L. Currey, B. J. Brecke, M. B. Green, and R. C. Fluck)
        Page 61
        Page 62
        Page 63
        Page 64
        Page 65
        Page 66
        Page 67
    Are no-tillage multicropping production methods profitable for Florida farmers? (D. L. Gunter, N. C. McCabe, and R. N. Gallaher)
        Page 68
        Page 69
        Page 70
        Page 71
        Page 72
        Page 73
        Page 74
        Page 75
    Alternative tillage in Jefferson County, Florida (L. A. Halsey and Phil Worley)
        Page 76
        Page 77
    Alternative tillage demonstration project agricultural conservation program (Betty Jones)
        Page 78
        Page 79
        Page 80
        Page 81
        Page 82
        Page 83
        Page 84
        Page 85
    Establishment of legumes in bahia grass sod (R. S. Kalmbacher)
        Page 86
        Page 87
        Page 88
        Page 89
        Page 90
        Page 91
    Conservation tillage systems in Florida-SCS viewpoint (J. D. Lawrence)
        Page 92
        Page 93
        Page 94
        Page 95
        Page 96
    Pest insects as affected by tillage methods in soybeans, corn, and sorghum (Ki-Munseki Lema, R. N. Gallaher and S. L. Poe)
        Page 97
        Page 98
        Page 99
        Page 100
        Page 101
        Page 102
        Page 103
        Page 104
        Page 105
        Page 106
        Page 107
        Page 108
        Page 109
        Page 110
        Page 111
    No-tillage in North Carolina (W. M. Lewis, A. D. Worsham, G. C. Naderman, and E. G. Krenzer)
        Page 112
        Page 113
        Page 114
    The influence of minimum tillage on populations of soilborn fungi, endomyiorrhizal fungi, and nematodes in oats and vetch (D. J. Mitchell, N. C. Schenck, D. W. Dickson, and R. N. Gallaher)
        Page 115
        Page 116
        Page 117
        Page 118
        Page 119
        Page 120
        Page 121
        Page 122
        Page 123
    Seeding and reseeding of cool-season forages in north Florida (G. M. Prine)
        Page 124
        Page 125
        Page 126
        Page 127
        Page 128
        Page 129
    Subsoiling: Minimum tillage and energy implications (F. M. Rhoads and D. L. Wright)
        Page 130
        Page 131
        Page 132
        Page 133
        Page 134
        Page 135
        Page 136
        Page 137
        Page 138
        Page 139
    Minimum tillage of corn in perennial sod: A three-year study with energy implications (W. K. Robertson, R. N. Gallaher, and G. M. Prine)
        Page 140
        Page 141
        Page 142
        Page 143
        Page 144
        Page 145
        Page 146
        Page 147
        Page 148
        Page 149
        Page 150
        Page 151
    No-tillage versus conventional tillage corn in bahia grass sod with soybeans following (R. L. Stanley, Jr. and R. N. Gallaher)
        Page 152
        Page 153
        Page 154
        Page 155
    No-tillage in Florida from a farmers viewpoint (Danny Stephens)
        Page 156
        Page 157
        Page 158
        Page 159
        Page 160
        Page 161
        Page 162
        Page 163
        Page 164
    Postemergence directed spray equipment and calibration (D. H. Teem)
        Page 165
        Page 166
        Page 167
        Page 168
        Page 169
        Page 170
        Page 171
    Soil and water conservation through double cropping (F. D. Tompkins, C. H. Shelton, and C. R. Graves)
        Page 172
        Page 173
        Page 174
        Page 175
        Page 176
        Page 177
        Page 178
        Page 179
    Soil fertility and its relationship to crop production cost in no-tillage systems (J. T. Touchton)
        Page 180
        Page 181
        Page 182
        Page 183
        Page 184
        Page 185
        Page 186
        Page 187
    Reducing energy inputs into no-tillage systems (A. C. Trouce, Jr. and Carl A. Reaves)
        Page 188
        Page 189
        Page 190
        Page 191
        Page 192
        Page 193
        Page 194
        Page 195
    Effect of plant population on yield, disease, and other parameters of soybeans planted no-till and conventionally (D. L. Wright, F. M. Shokes, and W. B. Tappan)
        Page 196
        Page 197
        Page 198
        Page 199
        Page 200
        Page 201
        Page 202
Full Text





PROCEEDINGS OF THE THIRD ANNUAL
NO-TILLAGE SYSTEMS CONFERENCE


THEME:

ENERGY RELATIONSHIPS IN MINIMUM TILLAGE SYSTEMS


Sponsored by
Agronomy Department
C. E. Dean, Chairman
Institute of Food and Agricultural Sciences
University of Florida
Gainesville, Florida 32611


Editor and Coordinator
Raymond N. Gallaher


June 19, 1980


S.oqY


TECHNG RSERC XTNSO










CONTENTS


Title and Author(s) Page

Preface
Raymond N. Gallaher VI

Comments of the Vice-President of the Institute of Food and Agricultural
Sciences.
K.R. Tefertiller VIII

Comments of the Dean for Extension
J.T. Woeste IX

Comments of the Dean for Research
F.A. Wood X

Pest Management Decisions in No-Tillage Agriculture
J. N. All 1

Minimum Tillage-One County Agent's View Point
J.A. Baldwin 7

Breeding Small Grains: Minimum Tillage and Energy Implications
R.D. Barnett, P.L. Pfahler, and H.H. Luke 9

Conservation of Energy in No-Tillage Systems by Management of Nitrogen
R.L. Blevins, W.W. Frye, and M.J, Bitzer 14

Double Cropping Soybeans Succeeding Soybeans in Florida
K.J. Boote 21

Weed Control Programs for No-Tillage Soybeans
B.J. Brecke 30

Deeper Rooting in Minimum Tillage to Conserve Energy
R.B. Campbell 33

Fuel Consumption and Power Requirements for Tillage Operations
R.P. Chromwell, J.M. Stanley, R.N. Gallaher, and D.L. Wright 37

Herbicide Tolerance and Wild Radish Contool in Lupine and Vetch
G.R. England, W.L. Currey, and R.N. Gallaher 42

Weed Control for No-Tillage Soybeans in Rye Straw
R.N. Gallaher and W.L. Currey 49

Subsoiling and Minimum Tillage of Corn on Florida Flatwood Soil
R.N. Gallaher and W.R. Ocumpaugh 54








CONTENTS CONTINUED

Title and Author(s)
Comparisons of Energy Requirements for Weed Control in Conventional and
No-Tillage Soybeans
J.M. Goette, W.L. Currey, B.J. Brecke, M.B. Green, and R.C. Fluck
Are No-Tillage Nilticropping Production Methods Profitable for Florida
Farmers?
D.L. Gunter, N.C. McCabe, and R.N. Gallaher
Alternative Tillage in Jefferson County, Florida
L.A. Halsey and Phil Worley
Minimum Tillage Demonstration Project Agricultural Conservation Program
(ACP)
Betty Jones
Establishment of Legumes in Bahia Grass Sod
R.S. Kalmbacher
Conservation Tillage Systems in Florida-SCS Viewpoint
J.D. Lawrence
Pest Insects as Affected by Tillage Methods in Soybeans,Corn, and Sorghum
Ki-Munseki Lema, R.N. Gallaher and S.L. Poe
No-Tillage in North Carolina
W.M. Lewis, A.D. Worsham, G.C. Naderman, and E.G. Krenzer
The Influence of Minimum Tillage on Populations of Soilborn Fungi,
Endomyiorrhizal Fungi, and Nematodes in Oats and Vetch
D.J. Mitchell, N.C. Schenck, D.W. Dickson, and R.N. Gallaher
Seeding and Reseeding of Cool-Season Forages in North Florida
G.M. Prine
Subsoiling: Minimum Tillage and Energy Implications
F.M. Rhoads and D.L. Wright
Minimum Tillage of Corn in Perennial Sod: A Three-Year Study with Energy
Implications
W.K. Robertson, R.N. GAllaher, and G.M. Prine
No-Tillage Versus Conventional Tillage Corn in Bahia Grass Sod with
Soybeans Following
R.L. Stanley, Jk. and R.N. Gallaher
No-Tillage in Florida From A Farmers Viewpoint
Danny Stephens

IV


I

I

Page


61


68




,3 I
76

78

I
86

I
92

S97

112


115

124 I

130 I


140

I
152

I
156


I











CONTENTS CONTINUED


Title and Author(s) Page

Postemergence Directed Spray Equipment and Calibration
D.H. Teem 165

Soil and Water Conservation Through Double Cropping
F.D. Tompkins, C.H. Shelton, and C.R. Graves 172

Soil Fertility and Its Relationship To Crop Production Cost in No-Tillage
Systems
J.T. Touchton 180

Reducing Energy Inputs Into No-Tillage Systems
A.C. Trouce,Jr. and Carl A. Reaves 188

Effect of Plant Population on Yield, Disease, and other Parameters of
Soybeans Planted No-Till and Conventionally
D.L. Wright, F.M. Shokes, and W.B. Tappan 196






I

PREFACE i

Climatic conditions in Florida and the Southeast are such that
multicropping should be fully utilized to harvest the ENERGY FROM THE
SUN and to meet the demand for agricultural products. Food and fiber
production must increase to satisfy the needs of a rapidly growing
population in Florida and the Southeast and to help meet the needs
created from national and world competition. -Producers must make
better utilization of their farmland on a year-round production basis
to offset increased costs of ENERGY inputs from fuelmachinery, chemicals,
and fertilizer as well as increased cost due to inflation, land prices,
taxes, labor, and interest.

Many multicropping systems can be more efficiently managed by
utilizing no-tillage operations in crop production. The no-tillage
method of producing crops consists of planting directly into an un-
prepared seedbed and the elimination of tillage operations through
harvest. No-tillage,offers producers an opportunity to reduce erosion,
conserve water, reduce labor, be timely in planting, reduce production
cost, increase the probability of growing two or more crops per year
on the same land(Multiple Cropping), and reduce FUEL use in crop pro-
duction. The no-tillage practice has become more popular during recent
years because of (a) the availability of planting equipment designed
to operate under unplowed stubble and/or mulched conditions, (b) the
development of improved herbicide to control grass and broadleaf weeds,
(c) the quality research conducted in recent years by agricultural
scientists, (d) the educational efforts with field days, demonstrations,
conferences, and shortcourses conducted by scientists in our state
University Cooperative Extension Services, and (e) of late, the spiriling
cost of ENERGY is causing producers to take a closer look at the use
of excess tillage. i

We initiated a coordinated program on Multicr6pping Minimum Tillage
Systems in Florida, beginning in 1976. Numerous faculty of the Institute
of Food and Agricultural Sciences at various Agricultural Research
Centers and the University of Florida at Gainesville, initiated multi-
cropping and/or minimum tillage research studies and demonstrations. We
are presently completing three and four years old studies and results are
beginning to become available for Florida farmers to use. Scientists
located throughout the Southeast are also involved in various aspects of
no-tillage. Cooperative efforts among Universities and other Federal and g
state agencies are increasing so that "know how" is more readily accessible
to our farmers.

This conference has been planned for extensive show-and-tell activities i
by scientists, governmental agencies, seed companies, fertilizer industries,
chemical industries, equipment companies, other companies and dealers and
by farmers. The main objective is to transfer information available on
no-tillage management to farmers and those who serve farmers with particular I
emphasise on energy conservation.

I


I

I








VII


Preparation for the "Third Annual Southeastern No-Tillage Systems
Conference" has been a difficult task and several people and organiza-
tions deserve acknowledgement. I personally wish to extend special re-
cognition to Mr. Rolland Weeks and his aAsistants Mr. J. David Massey,
Mr. Joseph K. McCoy and Ms. Suzanne Dyal for Mr. Week's leadership and
the hard work and talent they all have provided to make the conference
a success.

Miss Marily:;L. Copeland is appreciated for her time devoted part-
icularly to the typing, t&i&phone calls and headaches associated with
these proceedings. I also wish to express appreciation to Mr. Bruce A.
Fritz, Ms. Edwina L. Williams and Ms. A.D. Staples for their assistance
with messages and various other problems.

The Robinson Family of Williston, Mr. J. Raymond and his father Mr.
R.S. Robinson deserve special recognition for aiding in carrying out
this conference on their farm. Mr. Danny Stephens is acknowledged for
furnishing equipment and other help in making this conference a success.

Acknowledgements are extended to all faculty, administrators, stu-
dents, technical assistants, industry personnel, governmental agencies,
and farmers who have supported our efforts. Listed below are others who
have provided extensive support for us to carry out this conference:


Chevron Chemical Corporation
CIBA Geigy Corporation
BASF Wyandotte Corporation
Brown Mnaufacturing Co.
DeKalb Agresearch, Inc.
Florida Feed And Seed Company
FMC Corporation
Gold Kist Inc.
International Minerals and Chemical Co.
Kaiser Agricultural Chemical Co.
The Nitrogen Co., Inc.
Pioneer Hi-Bred International, Inc.
Coker's Seed Co.


W.O. McCurdy and Sons Seed Co.
Funks Seeds International
E.I. DuPont De Nemours and Co.
FMX Store Treton, FL.
Hatch Enterprises Bradford, FL.
Swick Farm Supply High Springs, FL.
J.C. Harden and Sons Banks, Alabama
Fauver Harvesting Service Sanford, FL.
Mr. Mont Brook Morriston, FL.


RAYMOND N. GALLAHER
Coordinator and Editor






/ M UNIVERSITY OF FLORIDA I
IFAS INSTITUTE OF FOOD AND AGRICULTURAL SCIENCES


GAINESVILLE, FLORIDA 32611
OFFICE OF THE VICE PRESIDENT I
FOR AGRICULTURAL AFFAIRS
1008 MCCARTY HALL
TELEPHONE: 904-392-1971 I


NO-TILLAGE SYSTEMS FOR THE THIRD ANNUAL SOUTHEASTERN
NO-TILLAGE SYSTEMS CONFERENCE I

The economic strength of our nation has depended heavily upon a
cheap and readily available energy supply. The agricultural sector has,
over the last fifty years, also become heavily energy dependent. The
short supply and high cost of energy can have a devastating effect on I
our ability to continue producing the safe, nutritious and reasonably
priced food supply needed by our citizens and for export. The escalat-
ing cost of production inputs and high interest rates are causing many
farmers today to consider whether to continue farming or not. 3

We at the University of Florida's Institute of Food and Agricultural
Sciences (IFAS) are addressing energy problems through extensive "low-
energy technology" research, extension and education programs. Florida
is taking a leadership role nationally in the development of low-energy
technology, and IFAS is heavily committed to this effort.

New technology usually takes time to develop. However, our multi-
cropping minimum tillage program is one example where we have low-energy
technology ready for the farmer's use. This "No-Tillage Systems Confer-
ence" is designed to show the technology available to our farmers and
the management practices that will work today. On behalf of IFAS, I
welcome you to this "Third Annual Southeastern No-Tillage Systems g
Conference". We trust that you will gain information that will aid you I
in lowering energy inputs while maintaining your production needs and
goals. Best wishes.


K. R. Tefertiller
Vice President for I
Agricultural Affairs

I


I


I

COL.ILGL. -F AGRICULTURE, ACGRICUjLTURAI. t XPI'lIME NT 'iTA rioNt COOPERATIVE EXTENSION SERVICE
.fCHOOL OFFOREST RESOURCES ANO CONSERVATION cI;t,.rN'i FOR TROPICAL AGRICULTURE
I 1h i 11isllfu1i ol Food ailnl Agricullurni SciUence)i is ii n Equal L:a ploytnltlll Oppor tuilily Atllhrmative Action Employer authorized to provide research,
educll lilona Informintion ajnd other services only to individuals aind institutions that fui lltioIl without regard to race, color, sex, or national origin.







I






I
rA


STATEMENT ON NO-TILLAGE SYSTEMS FOR THE THIRD ANNUAL SOUTHEASTERN
NO-TILLAGE SYSTEMS CONFERENCE


No-tillage systems, like many of the practices developed and

demonstrated by IFAS, are part of our effort to insure that

Florida Agriculture remains a competitive and compatible

industry. No-tillage systems are a good example of technology

being applied to reduce cost of production, conserve energy

inputs and enhance our national drive toward greater energy

independence and reduce both topsoil and water losses.

The success of our farmers in squeezing out production costs

is the major reason the American public has paid so little for

their food supply. Advancement of no-tillage technology should

help to insure continued increases in productivity on our farms

as well as the unequal contribution of the farmer to the overall

productivity in our country and the world.

We believe that highly reliable no-tillage systems will be

essential to Florida Agriculture. Florida's dependence on

petroleum energy under current technology demands our uncondi-

tional commitment to both immediate advances in productivity

and material reductions in our reliance on petroleum energy.

John T. Woeste
Dean for Extension
IX
The Institute of Food and Agricultural Sciences is an Equal Employment Opportunity Affirmative Action Employer authorized to provide research,
educational information and other services only to individuals and institutions that function without regard to race, color, sex, or national origin.
COOPERATIVE EXTENSION WORK IN AGRICULTURE AND HOME ECONOMICS, STATE OF FLORIDA. IFAS, UNIVERSITY OF
FLORIDA. U. S. DEPARTMENT OF AGRICULTURE. AND BOARDS OF COUNTY COMMISSIONERS COOPERATING


FLORIDA COOPERATIVE EXTENSION SERVICE
UNIVERSITY OF FLORIDA
INSTITUTE OF FOOD AND AGRICULTURAL SCIENCES


COOPERATIVE EXTENSION SERVICE AGRICULTURAL EXPERIMENT STATIONS
SCHOOL OF FOREST RESOURCES AND CONSERVATION COLLEGE OF AGRICULTURE

REPLY TO







/ UNIVERSITY OF FLORIDA

J mIFAS INSTITUTE OF FOOD AND AGRICULTURAL SCIENCES


GAINESVILLE, FLORIDA 32611
FLORIDA AGRICULTURAL EXPERIMENT STATIONS June 4, 1980
OFFICE OF THE DEAN FOR RESEARCH
1022 MCCARTY HALL
Tr-.IFPHONE 904-392-1784

STATEMENT OF NO-TILLAGE SYSTEMS FOR THE THIRD ANNUAL SOUTHEASTERN
NO-TILLAGE SYSTEMS CONFERENCE

Multiple cropping and minimum tillage are different but important approaches to I
increasing the productivity per unit of land and at the same time minimizing the
amount of energy required per unit of productivity. Neither approach to production
is oew, but each has assumed significantly greater importance in view of the energy
environment in which we live and the need to conserve energy wherever possible. The
integration of multiple cropping and minimum tillage practices has even greater
potential for increased production and improved efficiency in the utilization of
energy. Consequently, the Institute of Food and Agricultural Sciences of the
University of Florida has made significant increases in research programs in these
two important areas.

IlfS' multiple cropping/minimum tillage research program is statewide with emphasis 3
on vegetable and agronomic succession cropping systems and sod seeding interplant
systems. Variables in this array of studies include tillage practices, weed control
techniques, pest management techniques and strategies, irrigation, fertility, and
various crop sequences. The results of such investigations are made available to
agricultural industries in the state through a series of field demonstrations and
research and extension publications. I

Multiple cropping/minimum tillage research is truly a muntidisciplinary research
effort and as a consequence involves scientists from the commodity and discipline I
departments within IFAS. In addition, it does and will continue to involve very close
cooperation between and among scientists located in Gainesville with scientists
located at out-state research centers; our system of out-state research centers
provides an ideal setting for the development and evaluation of multicropping/minimum
tillage management systems. I am pleased with the research program that has been
developed in this important area and am confident that with results of these and
other related research programs, Florida's agriculture will continue to be competitive. I

It i. a pleasure to have you join us in the Third Annual Southeastern No-Tillage
Systems Conference and to have the opportunity to provide to you first-hand some
of the significant results of our research in this area.


F. Aloysius Wood I
Dean for Research

I


I
COLLEGE OF AGRICULTURE AGRICULTURAL EXPERIMENT STATIONS COOPERATIVE EXTENSION SERVICE
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PEST MANAGEMENT DECISIONS IN NO-TILLAGE AGRICULTURE


J. N. ALL


No-tillage (NT) systems involving corn are becoming increasingly popular in
the South because of the advantages apparent with these operations. NT is
especially useful in various types of multi-crop systems that take advantage
of the Southern resource of a long growing season. Non-continuous types of
NT in which some form of tillage is utilized in a multi-crop sequence are
most prevalent. Since corn often is planted later than normal in these
systems, it may be subjected to greater infestations by pests. Continuous
NT procedures are not as common in the South and usually are associated
with sloping terrain with high erosion potential. It is important to
distinguish between the two types of NT in a discussion of pest potential
because the ecosystems undoubtedly differ greatly. Thus, unless otherwise
specified the present discussion is concerned with non-continuous types of
NT.

The insect complex attacking corn in the South causes millions of dollars in
damage annually. For example, during 1976 in Georgia insect losses and cost
of control in conventionally tilled (T) corn exceeded $14 million, while
losses associated with virus diseases transmitted by insects was ca. $0.2
million (Suber and Todd 1980). Economic impact of pests in NT are not
available, but research indicates that most problems are comparable to T
systems (All and Gallaher 1976).

Much of the present discussion is based on research conducted over the past
6 years in over 50 experiments in Georgia in which various NT systems Were
compared directly with T cropping. The experiments were located in 6 areas
representing the major edaphic and climatic areas of Georgia. In the tests
all cropping practices (e.g. irrigation, planting date, subsoiling, insecticide,
hybrids, herbicides, cropping sequence) were the same in either tillage system
and the only difference was the tillage operation in T plots. Insect
populations were quantified using standard sampling procedures. Also
observations of pest problems were made in farmers' fields and a survey was
conducted of extension personnel, commercial pest managers, pesticide and
agricultural equipment distributors, and seed company representatives to
assess their views on pest potential in Southern NT systems.

Soil Insects Ecosystems are undoubtedly greatly different in NT and T systems,
and the variation is probably highest near the soil surface due to the presence
of debris from former crops in NT. These conditions can have variable effects
on soil insects.

The lesser cornstalk borer (LCB), Elasmopalpus lignosellus (Zeller), is a
polyphagous insect whose outbreaks in T corn are usually associated with
drought soil conditions (Dupree 1965). LCB infestations are substantially


J. N. All is Associate Professor of Entomology, Department of Entomology,
University of Georgia, Athens, Georgia 30602.






2

reduced in NT systems as compared to T systems (All and Gallaher 1977). I
This has been observed in over 30 experiments over a 6 year period and has
been observed in growers' fields. All and Gallaher 1977 pointed out that
higher soil moisture occurred in NT than T systems and proposed this as a
factor inhibiting survival of LCB in NT. Later research indicated that a
behavioral response of LCB is involved. Movement of radiolabeled larvae
in relation to corn seedlings was distinctly different in NT than in T. I
Larvae released 20 cm from corn seedlings quickly located the plants in the I
T system; seedlings in NT systems were not located for up to 7 days after
release (Cheshire et al. 1977, Cheshire and All 1978).
The billbug, Spenophorus callosus Oliver, feeds on various weeds, especially
nutgrass, Cyperus rotundus L., in the larval stage and attacks corn only as
adults. Overwintering adults migrate into corn fields from weeded areas and
may cause extensive damage, especially in fields planted early in the season I
(Morgan and Beckham 1960). S. callous produces damaging infestations in NT
corn, and research indicates that problems can be greater than in T systems. g
In a recent experiment near Midville, Ga., S. callosus damage was 32.1
infested plants/100 m row in NT as compared to 19.0 infested plants in the
T plots. The field had a moderate infestation of nutgrass that was poorly
controlled with planting time applications of herbicides and the higher
billbug populations were associated with the weed. Insecticide applications
at planting time (Durant 1975, All and Jellum 1977) and after plants emerge
(All and Jellum 1977) control S. callosus infestations in T systems; these
methods also are effective in NT systems (J. All unpublished data).
Other soil insects such as the Southern corn rootworm Diabrotica undecimpunctata
howardi Barber, seedcorn maggot Hylemya platura (Meigen), wireworms Melanotus
spp., white fringed beetle Graphognathus spp., cutworms Agrotis spp. larvae
have not developed quantifiable populations in experimental plots to assess
their biopotential in NT systems. Also no reports of major infestations of
these insects were expressed by the persons surveyed. However, damage to
corn by these insects must be of concern to entomologists, especially in
continuous NT systems where soil habitats are not periodically disturbed by
tillage operations.
Whorl Feeding Insects Important insects that infest the seedling stage of g
corn (not discussed as soil insects) in the South include the fall armyworm
Spodoptera frugiperda (J. E. Smith, armyworm Pseudaletia unipuncta (Haworth),
corn earworm Heliothis zea (Boddie), European corn borer Ostrinia nubialis
(Hubner), and the Southwestern corn borer Diatraea grandiosella (Dyar).
Observations of all these insects in Georgia indicate that greatest damage
can be anticipated in late corn plantings such as certain multi-crop systems
involving NT (All and Gallaher 1976). I
Infestations of fall armyworms are a major threat to corn in NT multi-crop
systems and are a factor that may limit the potential of certain of these g
systems in the South. Research indicates that tillage systems have little
impact on development of fall armyworm infestations (All and Gallaher 1976).
Close inspection of corn in experiments comparing NT and T systems at
various planting dates demonstrated that heavy infestations often occur in
both cropping systems planted after mid-May. Oviposition and larval populaLions
on 2-4 leaf stage seedlings developed more rapidly in T plots, but populations

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and damage were similar in 5-leaf stage plants. Yield losses were comparable
in either system. Efficacy of foliar insecticides was similar in either
tillage system (J. All unpublished data).

Severe armyworm damage has been reported in late planted NT systems (Wrenn
1975) and damage from the other whorl feeders should be of concern in
certain cases. However, our research indicates that the damage potential
of these insects is not enhanced in NT as compared to T.

Stalk and Ear Feeding Insects Many insects that attack these growth
stages in the South are also major pests in Northern states. However,
their reproductive potential often is enhanced in the warmer Southern
climate. For example, first generation European corn borer damage early
planted corn while second and third generation larvae infest corn of later
planting dates. Our research indicates that European corn borer infestations
are similar in NT and T systems. However, infestations were increased in
late plantings and these often are associated with NT practices in multi-
cropping sequences. We also noted a reduction in the number of infested
and lodged plants in irrigated plantings (both NT and T) as compared to
nonirrigated plants (All and Gallaher 1976). Low infestations of South-
western cornstalk borers were observed in Northwest Georgia during 1976-
1979. Whorl feeding and stalk borer damage were similar in either tillage
system (J. All unpublished data).

We have observed corn leaf aphid, Rhopalosiphum maidis (Fitch), infestation
of corn tassels in NT and T plots. In two experiments, extensive sampling
in fields with moderate johnsongrass populations (significantly higher in
NT than T) revealed that aphid colonization4of corn tassels was higher in
T (4.0 x 10 colonies/ha) than NT (2.7 x 10 colonies/ha) plots. However,
many johnsongrass plants had colonies and if these are coupled with the
aphid populations on corn, the overall Rumber of colonies in NT was 3.5 x
10 colonies/ha as compared to 4.5 x 10 /ha in T. Thus in this case, the
increased plant diversity of NT had a dilution effect on an insect popula-
tion infesting corn. In certain experiments substantially higher popula-
tions of a spittle bug, Prosapia sp, have been observed in NT as compared
to T plots. However, the numphal feeding on brace roots caused no apparent
damage to plants.

Corn earworm and fall armyworm infestations in corn ears in NT parallels
damage in T systems. Populations of both species were greater in plantings
associated with multi-cropping and delayed corn planting dates. Damage by
fall armyworm is especially severe in late planted corn with as many as 6
larvae causing complete destruction of some ears. Sampling indicated that
damage was reduced in irrigated as compared to non-irrigated plots in both
NT and T (All and Gallaher 1976).

Other insects associated with corn ears prior to harvest include sap beetles
(Nitidulidae), maize weevil complex (Sitophilus spp.), Tenebrionidae, and
Angoumois grain moth (Sitotroga cerealella (Oliver)), and these are serious
problems in the South. Infestations initiated in the field by these species
increase in stored grain (Floyd 1971). Also, these pests may be implicated
in distributing grain-infesting fungi such as Aspergillus flavus that






4I


produce mycotoxins in stored grain. Field infestations of certain of the
stored grain insects may be increased in certain NT systems where corn is
grown in the stubble of small grains. These insects are found in unharvested
grain and data suggests that populations move into corn prior to harvest i
(J. All unpublished data).
Heavy populations of the ring-legged earwig, Euborellia annulipes (Lucas), I
were observed in NT corn ears; significantly more infested ears were sampled
in NT plots (All and Gallaher 1976). These insects are not normally
considered pests of corn, but they can produce damage to grain. Feeding
near the tip of ears on the basal portion of the pericarp of kernels loosens
the grain so that it is easily detached. All life stages were observed and
as many as 10 individuals were counted in ears. 3
Epidemiology of Corn Virus Diseases Research indicates that two virus
diseases, maize chlorotic dwarf (MCD) and maize dwarf mosaic (MDM), are g
greater in certain NT systems (All et al. 1977, 1980). Leafhoppers transmit
MCD in corn; the blackfaced leafhopper, Graminella nigrifrons (Forbes), is
a major vector (Nault et al. 1973). Several aphid species transmit MDM,
including the corn leaf aphid (Williams and Alexander 1965). 3
The epidemiology of the diseases is complicated by the fact that both
viruses infect a variety of grasses including weeds (e.g. large crabgrass,
Digitaria sanguinalis (L). Scop., and johnsongrass, Sorghum halepense (L.)
Pers.) and small grains (e.g. winter wheat, Triticum aestivum L. Nault
et al. 1976). Johnsongrass is the only known perennial host of the pathogens
and in many areas it is an important factor in the spread of disease by I
acting as a reservoir of inoculum for vector transmission to corn (Damsteegt
1976).
We found that MCD and MDM were enhanced in NT as compared to T when johnson-
grass was poorly controlled by the herbicides paraquat and atrazine (All
et al. 1976). Data from these and other studies suggests that early season
control of johnsongrass is very important in reducing disease in corn.
Severity of the diseases is greater to young plants (Scheifele 1969), and
thus the presence of even low populations of johnsongrass in fields when
corn germinates greatly increases early season transmission by vectors.
Recent tests showed that the herbicide glyphosate effectively controls
johnsongrass in CT with corresponding reduction in disease (J. All unpublished
data). 3
Optimum pest management of MCD and MDM involves integration of several
control strategies to suppress the various factors involved in spread of
the diseases (All et al. 1980). Vectors of MCD are susceptible to systemic
insecticides (e.g. carbofuran) and hybrids are available that have disease
resistance (Kuhn and Jellum 1975, Pitre 1968, Kuhn et al. 1975, All et al. g
1976). Use of a resistant hybrid with a systemic insecticide was effective
in controlling leafhoppers and decreasing MCD in NT. Grain yield was
increased by up to 2333 kg/ha (All et al. 1977). Recent research in NT
systems showed that an integrated chemical control approach using a systemic i
herbicide (glyphosate) to control johnsongrass plus a systemic insecticide
(carbofuran) was highly effective (J. All unpublished data).

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In summary, insect potential in NT systems in the South varies with the
species involved and the type NT method. In general, non-continuous NT
systems that have some form of tillage operation within a 1 or 2 year
cropping sequence do not appear to develop greater insect infestations
than T systems planted at the same time. However, certain insects such
as billbugs produce greater damage in NT and concern must be shown for
corn virus disease problems in NT systems where johnsongrass populations
exist. Conversely, NT has control potential for lesser cornstalk borer.
Obviously the environment that develops in NT systems differs greatly
from T cropping, and the influence of these ecosystems on the biology of
pest insects must be studied on an individual basis. Research indicates
that standard control methods can be used in NT systems, but increased
effort is needed in refining chemical application methodology for NT.
Also, efforts in developing integrated pest management systems need to be
expanded for NT.

REFERENCES

1. All, J.N., and R.N. Gallaher. 1976. Insect infestations in no-tillage
corn cropping systems. J. Ga. Agric. Res. 17:17-9.

2. All, J.N., C.W. Kuhn, and M.D. Jellum. 1976. The changing status of
corn virus diseases: potential value of a systemic insecticide. J. Ga.
Agric. Res. 17:4-6.

3. All, J.N., C.W. Kuhn, M.D. Jellum, R.N. Gallaher, and R.S. Hussey. 1976.
Vector dynamics and epidemiology of maize chlorotic dwarf in minimum
tillage and conventional tillage cropping. XV International Congress of
Entomology. August 1976.

4. All, J.N., and R.N. Gallaher. 1977. Detrimental impact of no-tillage
corn cropping systems involving insecticides, hybrids, and irrigation
on lesser cornstalk borer infestations. J. Econ. Entomol. 70:361-5.

5. All, J.N., and M.D. Jellum. 1977. Efficacy of insecticide-nematocides
on Sphenophorus callosus and phytophagous nematodes in field corn.
J. Ga. Entomol. Soc. 12:291-97.

6. All, J.N., C.W. Kuhn, and M.D. Jellum. 1980. Control strategies for
vectors of virus and virus-like pathogens of maize and sorghum. Chp.
National Bull. Virus and Virus-like Pathogens of Maize and Sorghum. S-70
Tech. Comm. Virus and Virus-like Pathogens of Maize and Sorghum. In press.

7. Cheshire, J.M., Jr., Judith Henningson, and J.N. All. 1977. Radio-
labeling lesser cornstalk borer larvae for monitoring movement in soil
habitats. J. Econ. Entomol. 70:578-80.

8. Cheshire, J.M., Jr., and J.N. All. 1978. Monitoring lesser cornstalk
borer larval movement in no-tillage and conventional tillage corn systems.
J. Ga. Agric. Res. 21:10-4

9. Damsteegt, V.D. 1976. A naturally occurring corn virus epiphytotic.
Plant Dis. Rept. 10:858-61.






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10. Dupree, M. 1965. Observations on the life history of the lesser
cornstalk borer. J. Econ. Entomol. 58:1156-7.
11. Durant, J.A. 1975. Southern corn billbug (Coleoptera: Curculionidae)
control on corn in South Carolina. J. Ga. Entomol. Soc. 10:287-91.
12. Floyd, E.H. 1971. Relationship between maize weevil infestation in
corn at harvest and progressive infestation during storage. J. Econ.
Entomol. 64:408-11.
13. Kuhn, C.W., and M.D. Jellum. 1970. Evaluations for resistance to
corn stunt and maize dwarf mosaic diseases in corn. Ga. Agric. Exp.
Stn. Res. Bull. 82. 37 p.
14. Kuhn, C.W., and M.D. Jellum. 1975. Disease evaluation of commercial
hybrids. Ga. Agric. Exp. Stn. Res. Pap. 199. Pages 34-35.
15. Morgan, L.W., and C.M. Beckham. 1960. Investigations on control of
the southern corn billbug. Ga. Agr. Exp. Stn. Mimeo. Series N.S. 93.
9 p.
16. Nault, L.R., W.E. Styer, J.K. Knoke, and H.N. Pitre. 1973. Semi-
persistent transmission of leafhopper-borne maize chlorotic dwarf
virus. J. Econ. Entomol. 66:1271-3.
17. Nault, L.R., D.T. Gordon, D.C. Robertson, and O.E. Bradfute. 1976.
Host range of maize chlorotic dwarf virus. Plant Dis. Rept. 60:374-7.
18. Pitre, H.N. 1968. Systemic insecticides for control of the black-
faced leafhopper, Graminella nigrifrons, and effect on corn stunt
disease. J. Econ. Entomol. 61:765-8.
19. Scheifele, G.L. 1969. Effects of early and late inoculation of
maize dwarf mosaic virus strain A and B on shelled grain yields of
susceptible and resistant maize segregates of a three-way hybrid.
Plant Dis. Rept. 53:345-7.
20. Suber, E.F., and J.W. Todd. (Eds). 1980. Summary of economic losses
due to insect damage and costs of control in Georgia, 1971-1976.
Univ. Ga. Sp. Publ. 7:8-10.
21. Williams, L.E., and L.J. Alexander. 1965. Maize dwarf mosaic, a new
corn disease. Phytopathology. 55:802-4.
22. Wrenn, E. 1975. Armyworms launch heavy attack on many corn fields in
Virginia. S.E. Farm Press. July 2, 1975. p. 5, 28.

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MINIMUM TILLAGE ONE COUNTY AGENT'S VIEWPOINT

JOHN A. BALDWIN1


Each year in Levy County, numerous acres planted to corn and other
crops are damaged or destroyed by high winds and blowing soil traveling
across young stands of agronomic and vegetable crops. In some years,
soil erosion due to wind not only damages crops by "sand blasting" but
at times even reduces herbicidal activity by disturbing treated pre-
emergence areas.

Our deep sandy soils also lend themselves to leaching of nutrients as
well as compaction problems which potentially restrict root growth.
Continous tillage of row crop land by discing, harrowing and plowing
have created serious compaction problems in some of our deep sandy
soils at depths of six to twelve inches. Evidence of this has been
demonstrated by subsoiling two to three inches below this compacted
zone and comparing plant growth and yield to conventionally tilled
land.

In essence, as a County Agricultural Agent, it is important to keep
abreast of the latest technology and innovations in cropping systems
and tillage equipment. Inflationary times and increasing fuel costs
have increased the unit cost of production. Methods are needed to
reduce unit costs while maintaining or increasing current production
to make row crop production economical. Over production may create
marketing problems by reducing prices paid to growers, but it will be
up to producers to limit or restrict the acreage planted in order to
influence supply and demand. Economical and efficient production
practices are needed to maintain an economically sound agriculture
for Florida.

To utilize minimum tillage, a producer must evaluate his own set of
conditions on his farm. Soil types, crop rotations, managerial abil-
ities and other resources must all be evaluated.

The major advantages of minimum or reduced tillage have been demon-
strated to be; reduction of soil erosion, energy conservation, less
soil compaction, improved timing of crop establishment and planting
and in some instances, reduced machinery investment.

Some major disadvantages have also been observed. When corn is planted
in February or possibly Early March, soil temperatures may remain
lower during extended periods when a mulch system of minimum tillage
is used. Cold, wet soils may inhibit germination or early season root
growth. Insects, particularly soil insects such as cutworms, may be
more prevalent when heavy mulches of winter cover crops are used.
Also, producers will need to put their best managerial ability togeth-
er because there is less room for error under minimum tillage systems,
particularly under mulch systems of minimum tillage. More reliance is

John A. Baldwin is County Extension Director II, Levy County, Florida-
Cooperative Extension Service, Post Office Box 218, Bronson, Florida







8


needed on herbicides for weed control programs. Proper liming of soils
for optimum herbicide activity, timing of spray applications, proper
calibration of equipment and the potential use of directed sprays need
to be included in the management plan.

Producers should be cautioned to start on a small scale until sufficient g
experience is gained. They should also attend shortcourses, seminars,
demonstrations and field days to see and learn of multi-cropping, minimum
tillage systems.

It is a package approach. We do not want to plant into a weed field.
Plan through your County Extension Agent before implementing mimimum
tillage practices. A management plan to fit your particular farm and
resources will be needed. Planning before implementation of new farming
methods reduces chances of failure and insures proper scheduling of pro-
duction activities. Calling your County Agent when problems occur because
of poor planning often results in no recourse for a solution. The cropping
system and method of tillage should be well planned and fit to the indiv-
idual farm and management regime. The planting and management of the
succeeding or previous crop may be just as much or more important than
the current crop being grown under minimum tillage methods. Subsoiling
may not be needed in all instances, and fields should be inspected as
to need for subsoiling prior to planting. The subsoiling will require
more fuel and horsepower than doing strictly no-till plantings. Proper
weed identification and mapping of fields are extremely important in
the selection of proper herbicides for a given situation. A working
knowledge of minimum tillage practices is needed by County Agents. It
is essential that the agent make available to the producer the most cur-
rent information on minimum tillage.

Weather conditions affect our yields regardless of the cropping system
being used. The weather causes our greatest risk in row-cropping today.
We cannot control weather patterns but the use of minimum tillage in
many situations may help insure better growing conditions and reduce
adverse effects such as soil erosion, leaching of nutrients, inadequate
moisture at planting time, drought stress of crops, labor problems and
time.

As multiple cropping systems are put into practice by producers, more
intense use of available land will occur. As energy costs increase,
minimum tillage systems will fit more and more into the picture of modern
day agriculture.

Minimum Tillage acreage has increases since 1978, in Levy County. Corn, i
Soybeans and Grain Sorghum have been planted following winter rye and
the prior years' crop residues by minimum tillage methods. Several
thousand acres of pines have been clear cut in the past three years.
This will increase the potential of crop damage by wind erosion. Also,
energy costs are affecting our ability to irrigate economically. Minimum
tillage practices should help to reduce both wind erosion and soil mois-
ture losses. Again, we must learn to fit this system of cropping to
our land and management, keep current on production practices, and re-
member that a total management plan is needed to insure the best use
of canital and other resources.


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BREEDING SMALL GRAINS:
MINIMUM TILLAGE AND ENERGY IMPLICATIONS

R. D. BARNETT, P. L. PFAHLER, AND H. H. LUKE


Wheat, oats, and rye along with the clovers and ryegrass are used as the
winter annual components of many multiple cropping systems commonly used
in the southeastern United States. They can be used as forage or grain
crops, green manure, and cover crops, or as a weed suppressing and
moisture holding mulch for summer row crops. Small grains require relatively
low levels of input in the way of energy requiring fertilizers and pesticides.
They are able to utilize much of the nitrogen fixed by leguminous summer
annuals, such as soybeans and peanuts, that might be lost by leaching during
the winter months. They also are very efficient in the utilization of residual
fertilizers which have been applied to row crops. Small grains do require
fertilization but not nearly as much as most summer annual grass or vegetable
crops.

Small grains do not require nematicides or insecticides because these pests
are relatively inactive during the growing season of the small grains. Also,
they do not require herbicides because very few winter weeds are able to
compete with them.

There are three methods of establishing a small grain crop: 1) prepared
seedbed, 2) sod seeding into permanent pasture, and 3) aerial seeding into
standing crops. The prepared seedbed method is the best and most widely
used, though more costly. The major problem in sod seeding small grains
into summer grasses is that the summer grass is vigorously growing at the
ideal planting time for small grains. The summer grass must be grazed
very closely in order to obtain an acceptable stand of small grains. Sod
seeding is usually more successful with ryegrass or clover since their grow-
ing season does not overlap that of the perennial grass.

Aerial seeding is growing in popularity because it is cheaper, easier, and
faster than conventional methods and can be done into a number of crops
but works best in soybeans. The seed are disseminated from the air just as
the soybean leaves start to turn yellow, then the leaves fall covering the
seed. This works very well with adequate moisture but does not work well
during dry falls. It works best with the later-maturing soybeans since their
leaf fall comes at the optimum time to seed small grains. This system is used
quite extensively in the southeast for seeding rye and ryegrass for winter-
grazing.

Diseases are a major limiting factor to small grain production in Florida
because the mild winters are extremely favorable for the maximum develop-
ment of plant diseases. Minimizing the losses to disease requires an
integrated approach that includes crop rotation, deep plowing, timely plant-
ing, variety selection, and fungicides. Crop rotation is especially important
R. D. Barnett, Associate Professor of Agronomy, Agricultural Research and
Education Center, Route 3 Box 638, University of Florida, Quincy, Florida
32351. P. L. Pfahler is Professor of Agronomy, Agronomy Department, Uni-
versity of Florida, Gainesville, Florida 32611; H. H. Luke is Professor of
Plant Pathology, SEA, U. S. Department of Agriculture, Plant Pathology
Department, University of Florida, Gainesville, Florida 32611.
9






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in the case of wheat because several serious diseases build up if wheat
is grown on the same area year after year. Turning the soil, although
rather expensive and requiring high energy, would help reduce the initial
inoculum of several wheat diseases if wheat had recently been grown on the
same area. This practice reduces weed problems for the following summer
crop since many of the weed seed are buried. Also, any potential problem I
that might be caused from a herbicide used on the previous summer crop
would be reduced since the herbicide residue would be diluted into a
larger volume of soil. I

Fungicide seed treatments are a cheap way to avoid potential germination
problems. If the seed are not of top quality, seed treatment will often i
improve germination and insure a better stand. Seed treatments are
especially useful when planting in early fall when temperatures are high I
and seedling diseases are active. Seed treatments are helpful late in I
the season when the temperatures are rather low and germination is slow.
When the seedlings are below the soil surface over a long time period,
they are more susceptible to attack by seedling diseases.

Wheat is the most versatile of the small grains. It can be used as a
grazing, silage, hay, greenchop, green manure, or mulch crop. It can
also be used as a feed grain and most importantly as a food crop. The i
type of wheat grown in the southeast is soft red winter wheat. The flour
from this type of wheat is not used in bread but is used in cakes, cookies, g
donuts, crackers, etc. High quality soft red winter wheat should be low
in protein and have a high test weight. Excess nitrogen fertilization will
cause the protein content to be too high and results in poor quality wheat.

Diseases are one of the major limiting factors in wheat production. Leaf
rust, septoria glume blotch, and powdery mildew are all capable of causing
substantial yield losses and must be controlled either by the use of resistant
cultivars or fungicides. It is important in wheat production to adopt new
cultivars as soon as they become available because after a few years new
races of disease organisms develop and cause severe damage to the new
cultivars.

Increased wheat acreage in the southeastern United States has resulted in
sharp yield reductions caused by lack of rotation and seedborne infestation
by Septoria nodorum (13). Our observations and those of others indicate
that infested seeds are a major source of inoculum (10, 13) that might be
reduced by foliar fungicide applications (9) and by seed treatments. Other
work with fungicides has shown that yield increases may be obtained when
fungicides are used properly (3, 4, 8).

Planting late in the season reduces the damage caused by several important
pest of wheat, septoria, powdery mildew, and hessian fly. Some of the new
early-maturing cultivars of wheat perform well from later planting and they
fit into the multiple cropping systems better than the later-maturing cultivars.

All small grains provide excellent winter pasture but there are marked dif-
ferences among species and cultivars in their forage production. Under a
monthly clipping schedule, rye yields considerably more forage than the other I
smallgrains (11). When used as a silage or hay crop, oats perform better

I











than the other small grains (2). Rye produces more forage early in the
season, whereas oats and wheat produce most of their forage later in the
season.

There are also differences between cultivars in their season of forage pro-
duction. For example, Florida 501 oats produces significantly more forage
than Coker 227 in the fall but the reverse is true for spring forage pro-
duction. Oats can be planted about one month earlier in the fall than
rye or wheat because oats have more resistance to seedling diseases, and
are more tolerant of heat stress.

Rye is well suited to many multiple-cropping systems involving corn, peanuts,
and vegetables and especially those that require the small grain be re-
moved early as forage. Rye is better adapted than the other small grains to
infertile, sandy, acid soils and will produce a good crop with less fertilizer.
Rye grows at lower winter temperatures than the other small grains. It
makes an excellent mulch for no-till corn and is easily killed by herbicides.

The breeding program on rye is centered on leaf rust resistance and forage
production. Attempts to select types that have resistance to seedling
disease are being made. Hopefully these types can be planted earlier in
the fall. Tetraploid ryes that should do the same for rye production as
tetraploid ryegrass has the ryegrass production are being developed. The
tetraploids have larger seed and normally grow more vigorously than the
diploid cultivars. The tetraploids develop early and remain vegetative
longer in the spring than the diploid, and therefore, increase the length of
the forage production season.

A screening program for rye is in progress to develop types that can be
planted earlier for forage production. This has been done by planting the
rye one month before the earliest recommended date, mowing the plots
regularly during the winter, and then bulk harvesting the surviving plants.
A number of single plant selections were made in 1979 after 5 cycles had been
made. These will be increased and tested to determine if progress has been
made in the development rye that can be planted earlier.

Triticale, a synthetic crop derived from wheat x rye hybrids shows promise
for forage and feed grain production. Most of the research done with this
crop has been done during the last ten years. In clipping trials, triticale
produced less forage than rye but more than wheat in Florida (1). It is
equal to rye and wheat as a spring silage crop but is inferior to oats (2), and
is equal to or better than rye and wheat as a grazing crop (6). In Georgia,
triticale has been found lacking in winter-hardiness and forage production (7).
Progress has been made in improving grain quality and in developing shorter,
earlier maturing, higher yielding types. New cultivars recently tested in
Georgia (12), Alabama (14), and Florida (5) had higher grain yields than,
the best cultivars of the other small grains. The first cultivar developed in
the southeast was released during 1979 by Alabama A & M University (15). A
number of cultivars have been released in Texas. Only a limited amount
of triticale has been grown in the southeast.

Triticale produces vigorous, robust plants that are impressive in appearance
and yield better than the other small grains under stress conditions of limited




12
I
moisture or high temperatures. It has large seed which are less dense than
wheat. Slightly higher seeding rates may be required for triticale. Triticale
seems to have fewer disease problems than wheat and is somewhat difficult
to thresh. It appears to have some potential in minimum tillage, low energy
applications but has a marketing problem since there are no regular marketing
channels for triticale. Initial use will probably be restricted to the farms
where it is produced.
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REFERENCES CITED

1. Barnett, R. D., R. L. Stanley, Jr., W. H. Chapman, and R. L. Smith.
1971. Triticale: New feed grain and forage crop for Florida? Sunshine
State Agric. Res. Report. July-September. pp. 12-14.

2. Barnett, R. D., and R. L. Stanley, Jr. 1976. Yield, protein content, and
digestibility of several species and cultivars of small grains harvested for
hay or silage. Soil Crop Sci. Soc. Fla. Proc. 35: 87-89.

3. Barnett, R. D., and H. H. Luke. 1976. The effects of fungicides on
disease development, seed contamination, and grain yield of wheat. Plant
Dis. Reptr. 60: 117-119.

4. Barnett, R. D., and G. E. Sanden. 1978. Evaluation of various foliar
fungicides for the control of leaf rust on wheat, 1977. Fungicides and
Nematicide Tests 33: 113-114.

5. Barnett, R. D., and H. H. Luke. 1979. Grain yield and agronomic
characteristics of triticale in comparison with other small grains in Florida.
Soil Crop Sci. Soc. Fla. Proc. 38: 48-51.

6. Bertrand, J. E., and L. S. Dunavin. 1974. Triticale, alone and in a
mixture, for grazing by growing beef calves. Soil Crop Sci. Soc. Fla.
Proc. 33: 48-50.

7. Brown, A. R., and A. Almodares. 1976. Quantity and quality of triticale
forage compared to other small grains. Agron. J. 68: 264-266.

8. Kucharek, T. A. 1977. Profitable control of foliar diseases of wheat by
aerial application of zinc ion-maneb complex fungicide. Plant Dis. Reptr.
61: 71-75.

9. Luke, H. H., R. D. Barnett, and S. A. Morey. 1977. Effects of foliar
fungicides on the mycoflora of wheat seed using a new technique to assess
seed infestations. Plant Dis. Reptr. 61: 773-776.

10. Machacek, J. E. 1945. The prevalence of Septoria on cereal seed in
Canada. Phytopathology 35: 51-53.

11. Morey, D. D. 1973. Rye improvement and production in Georgia. Georgia
Agri. Exp. Sta. Res. Bull. 129.

12. Morey, D. D. 1979. Performance of triticale in comparison with wheat,
oats, barley, and rye. Agron. J. 70: 98-100.

13. Nelson, L. R., M. R. Holmes, and B. M. Cunfer. 1976. Multiple regres-
sion accounting for wheat yield reduction by Septoria nodorum and other
pathogens. Phytopathology 66: 1375-1379.

14. Sapra, V. T., and U. R. Bishnoi. 1979. Triticale improvement and product-
ion in Alabama. Alabama A & M University, Research Bulletin No. 1.

15. Sapra, V. T., J. L. Highes, G. C. Sharma, and U. R. Bishnoi. 1979.
Registration of Councill triticale. Crop Science 19:930.






I


CONSERVATION OF ENERGY IN NO-TILLAGE SYSTEMS BY MANAGEMENT OF NITROGEN

R. L. BLEVINS, W. W. FRYE AND M. J. BITZER


Energy conservation is a major concern and priority in agriculture today.
The inputs of fertilizers, pesticides, and fuels in crop production have
increased rapidly in recent years and farming is now a very energy depen-
dent industry. About 80 percent of the energy used by agriculture is
from liquid petroleum fuels and natural gas, which makes efficient use of
energy in agricultural production even more important. No-tillage
systems of crop production are one alternative for conserving energy.
Conventional tillage of corn and soybeans requires large amounts of fuel
in plowing and disking operations. Part of the fuel saved in no-tillage i
due to fewer trips across the field is offset by slightly higher amounts
of herbicides and, in some cases, higher rates of N fertilizer used for
no-tillage corn production.

The greatest single energy input into corn production is nitrogen fertil-
izer, representing almost one-half of the total energy input for no- I
tillage corn. Conclusions from earlier work in Kentucky (Thomas et al.,
1973; Blevins et al., 1977; M. S. Smith, Univ. of Ky., personal communi-
cation) which are pertinent to the N status under no-tillage compared to
conventional tillage include the following associated with no-tillage:

---Higher soil water content at the beginning of any particular rain-
fall event I
---Greater preservation of large soil pores by lack of tillage
---Slower rate of organic matter decomposition
---Less mineralization of N
---Higher immobilization of N.

These factors resulted in lower plant available N under no-tillage during
the growing season due to higher leaching loss of NO3, slower N release
from organic matter and greater immobilization. These results led to
recommendation of higher rates of N fertilizer for no-tillage corn pro-
duction than for conventional tillage. But, more recent comparisons of
yields of no-tillage and conventional tillage corn (Frye et al., 1978)
showed a greater response to N fertilizer, higher yields at higher N
rates, more efficient use of N fertilizer, and a lower input:output ratio I
of energy with no-tillage.


I


R. L. Blevins and W. W. Frye are Associate Professors of Agronomy
and M. J. Bitzer is Associate Extension Professor of Agronomy, Department
of Agronomy, University of Kentucky, Lexington, Kentucky 40546.

The investigation reported in this paper (No. 80-3-86) is in con-
nection with a project of the Kentucky Agricultural Experiment Station
and is published with approval of the Director.

14

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In this paper, we discuss the response of no-tillage corn to N fertil-
izer, compare the N efficiency in no-tillage and conventional tillage
systems, and suggest better ways to manage nitrogen in no-tillage corn
production. By improved management of nitrogen, energy is conserved or
used more efficiently.

Response to Nitrogen Fertilizer

A summary of corn yields from a long-term no-tillage and conventional
tillage experiment is presented in Table 1. On plots where no nitrogen
was applied the 10-year average corn yield was 76 bu/acre for no-tillage
and 95 bu/acre for the conventional tillage treatments. We conclude that
a combination of greater leaching losses, a slower rate of mineralization
and more immobilization of N resulted in lower yields and plants showing
more severe N stress during the growing season in no-tillage. Nitrogen
rates above 75 lb/acre resulted in slightly higher grain yield for no-
tillage compared with conventional tillage. The lower yields with no-
tillage at low levels of N fertilizer and higher yields at higher rates
of N fertilizer are similar to results reported by Bandel et al., 1975 in
Maryland and Moschler et al., 1974 in Virginia.

In our experiments (Table 1), highest yields were obtained during the
second and third years (1971 and 1972). Both of these years had a very
favorable distribution of rainfall for corn, whereas the first year
(1970) had low rainfall during the growing season. The high yield with
no nitrogen fertilizer is evidence that the soil initially had a high
potential for soil nitrogen mineralization. Yields produced in the tenth
year (1979) were comparable to the 10-year average, except for the
observed yield decrease in the zero nitrogen treatment of conventional
tillage. This suggests that corn yields can be maintained over a long
period of time in no-tillage as well as conventional tillage.

A comparison of yields on the Maury soil to yields on other well-drained
soils in Kentucky is shown in Table 2. Yields from no-tillage and
conventional tillage receiving 150 lb N/acre showed the highest yield
increase for no-tillage on the Crider silt loam soil. The Crider is a
deep, well-drained soil developed in residuum of limestone with a thin
layer of loess at the surface. The well-drained to moderately well-
drained sloping soils with moderate porosity seem best suited for no-
tillage systems in Kentucky. No-tillage on soils with high water table
or slow internal drainage often results in lower yields of corn than
conventional tillage. This is related to increased wetness due to the
surface mulch and cooler temperatures at planting time, which contribute
to lower plant stands, the development of stress conditions during early
stages of growth and, perhaps, denitrification loss of N.






16 I


Table 1. Summary of corn yields from limed plots on a Maury silt loam
soil at Lexington, Ky. with different levels of nitrogen and
no-tillage and conventional tillage systems. (Yields from
unlimed plots omitted for brevity.)


Nitrogen applied as NH4NO3 (Ib/acre)
Tillage
Year system 0 75 150 300
---------------bu/acre-------------


1970

1971

1972

1973

1974

1975

1976

1977

1978


NT
CT


118
130


89
129


99
90
166
180
153
161
119
123
154
162
97
80
144
129
106
123
78
100


99
90
170
159
149
159
126
129
165
163
100
82
156
141
109
127
85
97


105
90
173
162
155
165
121
135
167
162
106
96
170
141
115
132
99
100


1979 NT 73 118 123 121
CT 68 130 124 123

10-year NT 76 123 128 133
Ave. CT 95 128 125 131
t
NT = No-Tillage; CT = Conventional Tillage.


Table 2. Average corn grain yields produced on well-drained soils in
Kentucky by no-tillage and conventional tillage systems with
150 lb/acre N.


Grain yields
Number of Conventional
year tested No-tillage tillage
----------bu/acre----------

Maury silt loam 10 128 125
Crider silt loam 5 158 133
Allegheny loam 3 175 174










Nitrogen Efficiency

Table 3 shows the N fertilizer efficiency- values for the yield re-
sponses to each 75-lb increment of the 75- and 150-1b rates of N fertil-
izer for no-tillage and conventional tillage corn on the Maury soil at
Lexington which was shown in Table 1. Grain yields from each pound of N
fertilizer of both increments were greater for no-tillage than conven-
tional tillage. This may be somewhat misleading with regard to the first
increment, since the average yields with both the 0 and 75 lb/acre N
treatments were lower for no-tillage plots than for conventional tillage
(Table 1). But the efficiency values in Table 3 are based on increases
in yield resulting from the added nitrogen fertilizer. If one looks at
the yield response in Table 1 together with the N fertilizer efficiency
values in Table 3, the results suggest the need for slightly more N
fertilizer to obtain maximum yields in no-tillage; however, the nitrogen
fertilizer is used more efficiently. The more efficient use of nitrogen
in no-tillage corn is probably due to the soil moisture conserved by no-
tillage.


Table 3. Efficiency of nitrogen fertilizer in no-tillage and conven-
tional tillage corn grown on Maury soil at Lexington, Ky.
(Based on 10-year average yields.)


N fertilizer lb grain/lb Nt BTU in grain/BTU in N
N fertilizer
applied No-till Conventional No-till Conventional
1st 75 lb/acre 35.1 24.6 9.5:1 6.7:1
2nd 75 lb/acre 3.7 -3.7 1.0:1 -1.0:1

Calculated by subtracting yield without N fertilizer from yield with N
fertilizer and dividing by incremental amount of N fertilizer applied,
in this case, 75.
6,800 BTU/lb corn grain; 25,000 BTU/lb N.


Using a value of 25,000 BTU/lb of N, each lb is equivalent to less than
one quart of gasoline (145,000 BTU/gal) or about one pint of diesel fuel
(207,000 BTU/gal). Therefore, to realize the full effects of no-tillage
on energy conservation, it must be viewed in terms of improved energy
input:output ratio associated with higher crop yield or greater N effi-
ciency. Table 3 shows the N fertilizer efficiency values converted to
energy input:output ratios. They do not represent direct energy savings
but represent more efficient use of energy in no-tillage crop production.
No-tillage itself results in direct energy conservation through less fuel
consumption than conventional tillage. These data point out that the
energy saved with reducing tillage operations is not lost in additional N
fertilizer that may be recommended for no-tillage corn.


1/
- N fertilizer efficiency as used in this paper is grain yield with N
fertilizer minus grain yield without N fertilizer.






18 I



Effect of N Fertilizer Management Practices

Certain N fertilizer management practices may result in direct energy
savings or more efficient use of energy in no-tillage systems. These
practices may provide the N efficiency necessary to allow the farmer to
use no-tillage and obtain the energy conservation benefits associated
with it without requiring more N fertilizer to maintain yields equal to I
or greater than conventional tillage.

As pointed out previously, loss of NO by leaching during the growing
season was greater under no-tillage than under conventional tillage
(Thomas et al., 1973). N may be lost also by denitrification when soil
moisture remains above field capacity for periods of several days where
easily oxidized organic matter is present. These conditions often occur I
under no-tillage on soils with sticky clay subsoils or on soils with
fragipans that retard internal water movement. To avoid these losses, a g
split application or delayed application of N fertilizer 4 to 6 weeks
after planting has become an accepted and useful management practice in
Kentucky. Table 4 shows the results from a study of the optimum applica-
tion of N fertilizer for corn on a well-to moderately well-drained,
slowly permeable Hampshire silt loam soil. The delayed application of
150 lb/acre N as ammonium nitrate gave significantly higher yields.
Yields, N fertilizer efficiency, and energy efficiency are favored by
delaying the N fertilizer on soils with slow permeability.


Table 4. Effect of time of nitrogen application as ammonium nitrate on
no-tillage corn production on a Hampshire silt loam soil in
Franklin County, Ky.


Efficiency of N fertilizer
Yield lb grain/t BTU in gra n/
N applied (Ib/acre) (bu/acre) lb N added BTU in N
0 75 -
150 at planting 104 10.4 2.8:1
150 delayed 5 weeks 131 20.5 5.6:1 |
75 at planting + 75 delayed 135 22.0 6.0:1

Calculated by subtracting yield without N fertilizer from yield with N
fertilizer and dividing by the amount of N fertilizer applied (150).
6,800 BTU/lb corn grain; 25,000 BTU/lb N. I


Losses of N by leaching and denitrification are likely to be greater
early in the cropping season in Kentucky, accounting for the beneficial
effects of delaying application of N fertilizer. Fertilizer recommenda-
tions in Kentucky state that rates of N fertilizer can be decreased by 35
Ib/acre N, if as much as two-thirds of the N is delayed 4 to 6 weeks for
no-tillage corn on moderately well-drained soils and for conventional
tillage corn on moderately well and poorly drained soils. The N saved by
this practice represents about 875,000 BTU of energy or about 6 gal of
gasoline per acre. It should be pointed out, however, that the N











recommendation on soils with impaired drainage is 50 lb/acre more than on
well-drained soils if the N fertilizer is all applied at planting. Thus,
even with delayed application, at least 15 lb/acre more N is recommended
for soils with impaired drainage as a safe-guard against the greater
'potential N loss.

An additional management practice recommended for no-tillage corn pro-
duction on wet soils is delaying planting for 2 to 3 weeks later than the
recommended planting date for conventional tillage corn. This practice
usually results in a better stand of plants and allows application of N
fertilizer after the soil has dried out but before N demand is high in
the crop.

A nitrification inhibitor, nitrapyrin,/ sprayed onto granules of ammo-
nium nitrate fertilizer which was broadcast on the soil surface sub-
stantially increased yields of no-tillage corn in experiments over
several years at several locations in Kentucky (manuscript in review).
Yield increases ranged up to 46%, depending on soil and weather con-
ditions. The increased N fertilizer efficiency achieved by inhibiting
nitrification also would represent considerable energy efficiency.

Another approach to energy conservation through N fertilization is to
provide N to the no-tillage corn crop by growing winter-annual legumes as
cover crops. Winter cover crops included in this research in Kentucky
are hairy vetch, bigflower vetch, crimson clover and rye. Preliminary
results show that the legumes can provide substantial amounts of nitrogen
for no-tillage corn, with hairy vetch being more effective than the
others. In 1979, grain yields on plots with hairy vetch but with no N
fertilizer were statistically equal to yields on other plots with 88
lb/acre N fertilizer added. N fertilizer conservation of such a magni-
tude would represent considerable conservation of energy.

Summary

No-tillage production of corn requires considerably less tractor fuel
than conventional tillage, but N management is more critical due to
slower mineralization, higher immobilization and potentially greater
losses by leaching and denitrification of NO3. More N fertilizer may be
recommended for no-tillage corn, but the N is usually more efficient,
producing more grain/lb of N than under conventional tillage. Several N
management practices have been shown to improve N efficiency in no-
tillage experiments in Kentucky, thus contributing to energy conserva-
tion. These practices include delaying N fertilizer application for 4 to
6 weeks after planting corn, growing winter-annual legumes as cover crops
for no-tillage corn, spraying a nitrification inhibitor (nitrapyrin) onto
N fertilizer granules, and delaying planting on wet soil until it has
dried out and the potential for denitrification has diminished.




2/
S'Nitrapyrin, 2-chloro-6(trichloromethyl) pyridine, is manufactured by
Dow Chemical U.S.A., Midland, Mich.





20


These management practices along with the generally more efficient use of
N fertilizer in no-tillage allow farmers to obtain the energy conserva-
tion associated with fuel savings in no-tillage due to fewer trips across I
the field without having this advantage negated by application of higher
rates of N fertilizer. Through efficient N management no-tillage can be
both a direct and indirect energy conserving practice, and yields equal
to or greater than conventional tillage can be maintained.
References
Bandel, V. A., Stanislaw Dzienia, George Stanford, and J. 0. Legg. 1975.
N behavior under no-till vs. conventional corn culture. I. First
year results using unlabeled N fertilizer. Agron. J. 67:782-786.
Blevins, R. L., G. W. Thomas, and P. L. Cornelius. 1977. Influence of
no-tillage and nitrogen fertilization on certain soil properties
after five years of continuous corn. Agron. J. 69:383-386.
Frye, W. W., J. N. Walker, and G. A. Duncan. 1978. Comparison of energy
requirements for no-tillage of corn and soybeans. Agron. Abs. p.
16.
Moschler, W. W., D. F. Amos, R. W. Young, A. H. Kates, and D. C. Martens.
1974. Continuous no-till corn. In R. E. Phillips (ed.) Proceed-
ings of no-tillage research conference. University of Kentucky,
Lexington, July 16, 1974.
Murdock, L. W. 1974. No-tillage on soils with restricted drainage. In
R. E. Phillips (ed.) Proceedings of no-tillage research conference.
University of Kentucky, Lexington, July 16, 1974.
Thomas, G. W., R. L. Blevins, R. E. Phillips, and M. A. McMahon. 1973.
Effect of a killed sod mulch no nitrate movement and corn yield.
Agron. J. 65:736-739.
Triplett, G. W., Jr. 1975. Fertilizer use for no-tillage systems.
Proceeding of TVA fertilizer conference. Louisville, Kentucky, July
29-31, 1975.

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DOUBLE CROPPING SOYBEANS SUCCEEDING SOYBEANS IN FLORIDA


K. J. BOOTE


INTRODUCTION

Growing two crops during the warm season is possible in much of Florida
where soil temperature is adequate and the frost-free period exceeds 240
days. Soybean (Glycine max L. Merr.), because of its photoperiodic sensi-
tivity, is usually planted as the second crop, either after a cool season
cereal or after a warm season crop such as vegetables, melons, or early
maturing corn (Zea may L.) in Florida (Guilarte et al., 1975; Prine et al.,
1978; Gallaher et al., 1979). However, experiments in Florida by Boote
(1977, 1980) demonstrated that early maturing soybean cultivars can be
planted in March for maturity in late June, with sufficient time to plant
a second warm season crop, such as adapted late-maturing soybeans (Guilarte
et al., 1975; Prine et al., 1978; Akhanda et al., 1976).

In order to produce two soybean crops per year, the first crop must be
planted early to a cultivar from early maturity groups (less than group V)
so the crop will progress rapidly into seed growth and mature by late June
(Boote 1977, 1980). The optimum Maturity Group (MG) for the first crop was
Group III, although Groups II and IV were acceptable. When planted in March,
cultivars of MG V through VIII were induced to flower by the initially short
days, but the accelerating daylengths delayed subsequent reproductive develop-
ment and delayed maturity until September-October (Boote, 1977, 1980). Thus
planting a second soybean crop was not feasible after MG V, VI, VII, VIII
and later cultivars. Long photoperiods after flowering have been shown to
prolong post-flowering development and reduce partitioning of dry matter to
seeds (Johnson et al., 1960; Lawn and Byth, 1973; Raper and Thomas, 1978;
Thomas and Raper, 1976). Hartwig (1954) observed flowering at 49 and 41
days after emergence for MG VI and VII cultivars planted April 10 at Stone-
ville, MS (latitude 330 20' N), but reported that the plants aborted nearly
all early flowers and matured in October.

In addition to cultivar selection, March-planted early maturing soybeans may
encounter several other problems including the hazard of late frosts and cool
soil temperature which causes slow emergence and reduced early growth (Hart-
wig, 1954). When planted in lower latitudes including Florida, early matur-
ity groups flower early, are short, and set their pods lower (Whigham and
Minor, 1978; Boote, 1977). Incomplete canopy cover can be overcome by plant-
ing in narrow rows, but low pod set remains a more challenging problem.

This paper addresses the feasibility of double cropping soybeans succeeding
soybean. Specific objectives were to evaluate soybean cultivars in a range
of Maturity Groups for yield, reproductive development, and suitability as
the first crop in double cropping systems or as the second crop in double

K. J. Boote is Associate Professor of Agronomy, Department of Agronomy, 304
Newell Hall, University of Florida, Gainesville, FL 32611.






22 i


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cropping systems in Florida, and to evaluate row spacing, planting methods,
and other cultural practices needed to grow two soybean crops per year in
Florida.

MATERIALS AND METHODS 3

First Crops: Soybeans were grown during the spring seasons (1976-1979) at
the University of Florida Agronomy Farm, Gainesville, FL (Latitude 290 40'
N). The soybean cultivars and planting dates are listed in the Tables. 1
The soil type in the experimental areas was Kendrick sand, a loamy, siliceous,
hyperthermic Arenic Paleudult in 1976, 1978, and 1979; and a Gainesville sand,
a hyperthermic, coated Typic Quartzipsamment in 1979. Soil pH was at recom-
mended levels or corrected by preplant dolomite addition. Fertilizer (40
kg N, 35 kg P, and 133 kg K) was incorporated before planting the first crop.
The fields were plowed and disked prior to planting. Agricultural chemicals g
are given as active ingredients per hectare. Nematode control was furnished i
in 1976 and 1977 by injecting 26 kg/ha of 1,2-dibromo-3-chloropropane. In
1978, fenamiphos (ethyl-3-methyl-4-(methylthio)phenyl(l-methylethyl)phosphor-
amidate) was disked in at 7.5 kg/ha. No nematocide was used in 1979. Weeds
were controlled with pre-emergence herbicides: in 1976, 2.2 kg/ha alachlor
(2-chloro-2', 6'-diethyl-N-(methoxymethyl)acetanilide) and 2.5 kg/ha dinoseb
(2-sec-butyl-4,6-dinitrophenol); in 1977, 1.3 kg/ha benefin (N-butyl-N-ethyl-a,
a,a-trifluoro-2,6-dinitro-p-toluidine), 2.6 kg/ha vernolate (S-propyl dipropyl
thiocarbamate), 2.2 kg/ha alachlor, and 2.8 kg/ha dinoseb; in 1978, 1.3 kg/ha
benefin; in 1979, 1.3 kg/ha benefin, 2.2 kg/ha alachlor, 2.2 kg/ha naptalam
(N-l-naphthylphthalamic acid), and 1.1 kg/ha dinoseb. Moderate herbicide
injury, probably from vernolate, was observed in 1977. Foliar feeding in-
sects were not a problem; however, 0.5 kg/ha of methomyl (S-methyl-N-((methyl-
carbamoyl)oxy)thioacetimidate) was applied 25 May 1976 for an infestation of
southern green stinkbug (Nezara viridula L.). Plots were irrigated to supple-
ment rainfall during the season.

The experimental design was a randomized complete block. Replications numbered i
three, six, four, and four in 1976 through 1979, respectively. Seeds were
planted in 31-cm rows in 1976 and 1977, 25-cm rows n 1978, and 35-cm rows in i
1979. Seeding density ranged from 56 to 64 seeds/m Each plot consisted
of five or six rows 5 m long of which the center three or four rows were har-
vested for yield.

Reproductive development of cultivars was observed as days from emergence to
R1 (50% of plants having one flower), R4 (50% having a 2.0 cm long pod any-
where on the plant), R5 (50% having detectable bean swelling in any pod),
and R8 (95% of the pods at mature color). The reproductive stages differ
slightly from those of Fehr et al (1971) and Fehr and Caviness (1977) in that
R3, R4, and R5 stages pertain to pods at any node on the plant rather than
at the top four nodes having fully-expanded leaves.

The soybeans were hand-harvested a few days after reaching R8 maturity, warm
air-dried, and threshed. Yield of clean seed per plot was based on harvested
areas (bordered middle rows) of 4.46 m2 in 1976 and 1977, 4.34 m2 in 1978,

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and 5.12 m2 in 1979. Average height to tip of main stem was measured at
maturity. Seed quality was rated on a scale of 1 (very good) to 5 (very
poor). Weight per 100 seeds was determined. To estimate combine harvest-
ability, at least 50 cm of bordered row was cut into two segments; soil
line to 8 cm, and above 8 cm. Individual segments were threshed separately
and percent seed weight below 8 cm height was determined. All data on re-
productive development and yield characteristics were subjected to analysis
of variance. Cultivar means were compared by the new Duncan's Multiple
Range test. The error term was the cultivar by replication mean square.

Second Crop: The second crop 'Cobb' soybeans were planted 30 June 1977, 29
June 1978, and 27 June 1979 in 92, 46, and 35-cm rows, respectively. Tillage
prior to the second crop consisted of disking in 1977, plowing and disking
in 1978, and no-tillage in 1979. No nematocide or additional fertilizer
was applied. Alachlor, at 2.2 kg/ha was used all three years for weed
control with addition of 2.2 kg/ha of glyphosate (N(phosphonemethyl)glycine)
on no-tillage plots in 1979. Cultivation was done in 1977 and 1978. The
second crops were irrigated in 1978 and 1979. Insecticides were needed in
1978 and 1979. Four yield replicates were harvested each year from border-
ed rows similar in area to the first crop. Yield and maturity characteris-
tics were handled similarly to the first crop. To convert kg/ha to Ib/ac,
multiply by 0.892. Divide lb/ac by 60 to obtain bu/ac.

RESULTS AND DISCUSSION

Cultivars with Suitable Reproductive Development for First Crop: Maturity
data from 1976 and 1979 (Table 1) shows cultivars from a range of Maturity
Groups (MG). Maturity data from 1977 and 1978 were intermediate to those
in 1976 and 1979. Reproductive development and maturity was prolonged in
1976, partially due to season and partially due to southern green stinkbug
damage. In 1979, the only year nematocide was not applied, nematode injury
may have hastened reproductive development and senescence, especially for
the'first three cultivars listed.

Cultivars in MG 00 through I including 'Corsoy' (MG II) flowered early (29
days after emergence) and did not differ significantly in days from emer-
gence to RI, R4, and R5. However, they differed up to 6 days in time to
maturity. Maturity Group II, III, and IV cultivars flowered 1 to 2 days
later; thereafter, each respective MG was progressively somewhat slower in
reaching each successive reproductive stage. The largest difference among
MG 00 to IV cultivars occurred in days from R5 (bean swell) to R8 (95% pod
maturity). The slightly slower reproductive development of MG II, III, and
IV cultivars contributed to taller plants with 1 to 2 more nodes, but the
significantly longer pod fill period (R5 to R8) gave these cultivars a con-
siderable yield advantage over MG 00, 0, and I (Table 2).

The MG V, VI, and VII cultivars were delayed in flowering and slower in
reproductive development than MG IV and earlier cultivars. They flowered
at least 10 days later than MG IV cultivars. The substantial shift in
reproductive behavior from MG IV to MG V is noteworthy. Reproductive











behavior of 'Essex', typical of MG V, was more comparable to that of MG VI
and VII than to that of MG IV. 'Hill' does not exhibit flowering behavior
typical of MG V (K. Hinson, personal communication). Cultivars later than
MG IV required 3 to 20 more days from R1 to R4 than did earlier MG's. Most
of this delay was lag time before any active pod elongation. Subsequent
reproductive development (R5 to R8) was also prolonged for MG V to VII
cultivars. Essex and Hill set a reasonable pod load, but later cultivars
such as 'Bragg' (MG VII) remained green and set pods at a very slow rate
and did not mature until the normal time in October. Essex and Hill had
80 to 90% mature pods by 25 July and 31 July, respectively, but the re-
mainder of the pods stayed green, and the plants retained one-third of
their green leaf area at that time.

Table 1. Reproductive development of soybean cultivars planted in March
of 1976 and 1979 at Gainesville, FL.

Cultivar Maturity Nodes
Group at Reproductive Development Stage
Maturity R1 R4 R5 R8
--------days after emergence--------
----------March 1976t ----- -- --
Fiskeby V 000 30ef* 38f 45f 77f
Altona 00 29f 38f 46ef 81e
Portage 00 29f 38f 46ef 82e
Clay 0 29f 38f 46ef 82e
Evans 0 30ef 38f 47ef 86d
Hodgson I 29f 38f 47def 87d
Steele I 30ef 39f 47def 85d
Corsoy II 29f 39f 47def 93c
Amsoy 71 II 31d 41e 48cde 94c
Williams III 32cd 42d 49cd 99b
Calland III 31de 42d 49c 109a
Cutler 71 IV 33c 44c 52b 109a
Bonus IV 33c 44c 50bc 108a
Hood VI 52a 71a 76a
Bragg VII 45b 68b 75a
-- -- -----15 March 1979-----------
Maple Arrow 00 6.4e* 28e 37g 40f 76h
Amsoy 71 II 8.1d 29de 39fg 43e 79g
Woodworth III 8.6d 29de 39fg 42e 82f
Williams III 9.7c 30cd 40ef 43de 88e
Union IV 10.lbc 31cd 41cd 46c 90d
Franklin IV 9.8c 30cd 41de 44d 89de
Cutler 71 V 10.9a 32c 42c 46c 93c
Essex V 10.7ab 42b 56b 61b 124b
Hill V 11.3a 52a 64a 69a 131a

* Means in a column within a given year not followed by the same letter
are significantly different at the 0.05 level according to Duncans New
Multiple Range test.
t Results for 1976 averaged over three planting dates: 8, 18, and 29
March, and three replications per planting date.


24 I


I











The cause for this abnormal reproductive behavior is the sensitivity of each
particular genotype to photoperiod. The later the MG of a cultivar, the
shorter days it requires to successfully complete reproductive development.
When planted in March, the days were short enough to induce flowering and
pod set of these later cultivars. But the subsequently lengthening days of
May, June and July affected reproductive development even though flowering
had been initiated. The later the MG, the more sensitive it is to the effect
of a given lengthening photoperiod on reproductive development (Major et al.,
19.75). This means that only certain combinations of cultivars and planting
dates will fit for an early soybean crop at a given temperature-and-increas-
ing-daylength location. For Gainesville, MG V and later cultivars planted
in March were adversely affected by daylength and matured too late to allow
a second crop. In fact, they produced less and poorer quality seed than if
planted 'at recommended dates (May-June). MG II, III, and IV cultivars were
early enough to allow a second crop.

Yield Characteristics of First Crop Soybean Cultivars: Good yield levels
were achieved in all four years under conditions of narrow rows, irrigation,
and good weed control. A comparison of yield characteristics to maturity
group indicates MG 000 to I cultivars were uniformily early, short and low
yielding, with low pod set (Table 2). Their low yield potential can be
attributed to a short filling period (days from R5 to R8). Successively
later maturity groups were later maturing, taller, had poorer quality seed,
and set fewer seeds below 8 cm. Potentially economical yield levels were
generally achieved with MG III and IV cultivars which matured between June
20 and 30 at Gainesville if planted March 14. 'Amsoy 71' of MG II also
yielded well, except in 1979 when no nematocide was used. 'Williams' (MG
III) was probably the most consistently good performer over the years. This
agrees with Williams' unusually good adaptation in INTSOY's tropical-subtropi-
cal trials inspite of being in MG III (Whigham, 1975; Whigham and Minor, 1978).
Certain other MG III and IV cultivars: 'Woodworth', 'Bonus', and 'Franklin'
yielded significantly less than Williams. 'Union', being of Williams parent-
age, appeared similar to Williams. While 'Calland' (MG III) and 'Cutler 71'
(MG IV) were tall and yielded well, they had some negative attributes: poorer
seed quality, later maturity, and a tendency to maintain green stems and a
few green leaves at maturity, possibly in response to lengthening days. This
"staygreen" trait was even more pronounced on MG V cultivars which "matured"
with poor quality seed in late July, but retained about one-third green leaves
and about 10-20% green pods. While the plant and pod height of MG IV cultivars
is desirable, their poorer seed quality and later maturity conflict with prompt
early harvest in the warm humid rainy season in Florida which arrives in late
June. Delayed maturity and harvest delays planting and reduces the growth
period of the second soybean crop.

Second crop soybeans and total seed yield from two crops. Second crop 'Cobb'
soybeans were planted June 30, June 29, and June 27 after harvesting early
soybean crops in 1977, 1978, and 1979, respectively. First crop 'Williams'
yield, second crop 'Cobb' yield, and combined yield of two crops is shown in
Table 3. The yield potential of the second crop in 1977 was limited by incom-
plete canopy cover in 92 cm rows and growth under rainfed conditions. The






26
Table 2. Yield characteristics of soybean cultivars planted in March of
1976, 1977, 1978, and 1979 at Gainesville, FL.

Height Yield
Maturity Maturity at Seed below Seed
Cultivar Group Date Harvest Yield 8 cm Qualitytt

cm kg/ha % 1-5
--- --------March 1976t- ---- --
Fiskeby V 000 6-5f* 33g 1890d 24a 1.6e
Altona 00 6-9e 53e 2600b 12def 1.8de
Portage 00 6-10e 51e 2610b 9efg 2.0cd
Clay 0 6-10e 45f 2150c 17abcd 1.7de
Evans 0 6-14d 47f 2590b 12cdef 1.8de
Hodgson I 6-15d 47f 2330c 14bcde 2.0cd
Steele I 6-13d 48f 2660b 17abcd 1.7de
Corsoy II 6-21c 52e 2910a 18ab 2.3bc
Amsoy 71 II 6-22c 59d 3110a lldef 2.4bc
Williams III 6-27b 66c 3000a 10efg 2.4b I
Calland III 7-7a 75b 3010a 7fg 3.4a
Cutler 71 IV 7-7a 83a 2920a 5g 3.4a
Bonus IV 7-6a 78b 2650b 9efg 3.2a
------ -14 March 1977-- --
M65-217 00 6-8e 36d 2130bcd 22abc 1.3f
Altona 00 6-3f 39d 1940cd 20bc 1.5def
Portage 00 6-4f 37d 1800d 12c 1.8bc
Maple Arrow 00 6-9d 40d 1990cd 21bc 1.4ef
Evans '0 6-9d 36d 2280bc 28ab 1.8bcd
Corsoy II 6-14c 45c 2390b 31a 2.0ab
Amsoy 71 II 6-16b 55b 2990a 19bc 2.2a
Williams III 6-20a 60a 3200a 17c 1.7cde
--14 March 1978--
M65-217 00 6-12c 41c 1800b 27b 1.9b
Prize II 6-12c 36c 1540b 41a 2.4a
Amsoy 71 II 6-19b 52b 2630a 22bc 2.0b
Williams, III 6-22a 54b 2760a 12c 2.Ob
Franklin IV 6-24a 60a 2320a 13c 2.2ab
------- --15 March 1979-- -- -
Maple Arrow 00 6-7h 28h 1580d 12a 1.4f
Amsoy 71 II 6-10g 40g 1830d 10ab 1.7def
Woodworth III 6-13g 45f 1980cd 9abc 1.6ef
Williams III 6-19e 51e 2800b 4cd 1.7def
Union IV 6-21d 55d 2900ab 6bcd 2.Ode
Franklin IV 6-20de 60c 2370c Id 2.0d
Cutler 71 IV 6-24c 65b 2840ab Id 2.7c
Essex V 7-25b 55d 3280a # 3.2b
Hill V 8-la 72a 1880d # 4.3a

*Means in a column within a given year not followed by the same letter are
significantly different at the 0.05 level.
t Results for 1976 averaged over three planting dates: 8, 18, and 29 March.
Maturity dates for 1976 adjusted to a hypothetical 14 March planting date
to allow comparison to the other three years.
tt1 = Very Good; 5 = Very Poor.
# Not measured, but was less than 3%. U











yield potential of both the first and second crop in 1978 were limited by in-
sufficient irrigation frequency in a dry season coupled with a sting nematode
infestation in one-third of the experiment. In 1979 the two crops received
nearly optimum irrigation and rainfall frequency, but received no nematocide.
The excellent weather is reflected in the high yields for 1979. The 1979
yields were 2800 kg/ha (42 bu/ac) plus 3410 kg/ha (51 bu/ac) for a total of
621.0 kg/ha (93 bu/ac) per season. Even under the adverse conditions of 1978,
total yield was 4400 kg/ha (65 bu/ac), a yield more than twice the state aver-
age. The second crop responded well to narrow row spacing with a 30% increase
in 1978 from 46 versus 92 cm rows and a 9% increase in 1979 from 35 versus 105
cm 'rows. The cultivar Bragg yielded as well as Cobb in the two years it was
planted.

Table 3. Total yield of 'Cobb' soybeans succeeding 'Williams' soybeans
during 1977, 1978, and 1979 at Gainesville, FL.

Row Planting Maturity Seed Total
Year Crop Cultivar Spacing Date Date Yield Yield
cm kg/ha kg/ha
1977 First Williams 31 3/14 6/20 3200
Second Cobb 92 6/30 10/30 2070 5270

1978 First Williams 25 3/14 6/22 2760
Second Cobb 46 6/29 10/29 1640 4400

1979 First Williams 35 3/15 6/18 2800
Second Cobb 35 6/27 11/1 3410 6210

Tillage conditions differed for the second crops in each year. Disking in
1977 was not satisfactory, because it provided a good seed depth in which
first crop soybeans volunteered in the second crop. This was not desirable,
because volunteers from first crop seed were short, matured early, and had
poor seed quality by the time the full season crop was mature. In other words,
first crop volunteer soybeans acted like 'weeds'. Morever, the low pod set
of the first crop is likely to result in sufficient cutter bar loss to give
a volunteer soybean problem. After the 1978 early crop, the field was plowed
with a moldboard plow to bury the seed lost during harvest. This worked, but
the second crop was planted in dry soil and irrigated too heavily. Emergence
and-stand was reduced by soil compaction and weed pressure increased. In 1979,
the second crop was seeded no-till into the residue left from the first soy-
bean crop. Lasso-Roundup (2.2 kg/ha alachlor and 2.2 kg/ha glyphosate) were
applied to control future weeds as well as weed escapes from the first crop.
The second crop in 35 cm rows covered the ground quickly and weeds were not
a problem. This no-tillage method effectively solved the volunteer soybean
problem, controlled weeds, maintained soil moisture for germination, and
speeded replanting with lower energy input.

Conclusions and Recommended Cultivars and Practices for Growing Soybeans
Succeeding Soybeans in Florida: March-planting of soybean cultivars in MG
000 to VIII during four years indicated that the cultivar for the first crop






28


I
should be from MG II, II or IV for best yield potential, seed quality, suffi-
cient pod and plant height, and sufficiently early maturity to allow a second
crop. Williams was the best performing cultivar, but Union, Cutler 71, and I
Amsoy 71 were also good within MG II to IV. Cultivars from MG V, VI, VII,
VIII, and IX, when planted in March, were adversely affected by the lengthen-
ing days. As a result their reproductive development was slow and they
matured too late to allow planting a second crop.

Growing two soybean crops per year will require careful management. The first I
crop must be planted no later than the end of March on well-drained, productive 1
soils that have previously produced good soybean yields. Irrigation and good
weed control are absolutely essential. Plant in narrow rows at populations
near 60 plants per m2 (Table 4). This will give a closed canopy and reduce
weed competition. Yield was increased 21% by planting in 25cm as compared to
102 cm row spacing. Yield was not increased by doubling seeding rate to 112
seeds/m2. The fraction of seed yield below 8 cm was reduced by either greater 3
in-row plant competition (fewer rows at the same area planting density) or by
greater overall planting density at the same in-row competition. Because pods
are set low, careful combine harvest and low cutter bar height are needed.
Harvesting at the earliest possible time is essential to prevent loss of seed I
quality in the warm humid summer and to give maximum growing time for the
second crop planted. Spraying a harvest aid desicant such as paraquat (1,1'- I
dimethyl-4,4'-bipyridinium ion) may be desirable if the last few leaves fail
to die as pods begin to mature. Seed drying may be needed.

The second crop should be a full-season adapted cultivar. Bragg (MG VII) and
Cobb (MG VIII) have performed better than the few MG IX experimental lines
tried. Best yield performance of the second crop occurred in years when no-
till planting methods, narrow rows, optimum irrigation was practiced. The
.- - -- .------.-----. -


Table 4. Effect of row spacing and population on yield characteristics of
'Amsoy 71' and 'Williams' soybean planted 14 March 1978 at Gaines-
ville, FL.
Harvest Height Yield Weight
Row Plant at Seed below of 100 Seed
Cultivar Spacing Density Harvest Yield 8 cm Seed Qualitytt
cm no/me cm kg/ha % g 1-5
Amsoy 71 25 47 52a* 2630a 22a 17.9abc 2.0a
51 51 53a 2400a 15b 17.6bc 2.2a
51t 99t 53a 2370a 2c 16.9c 2.2a
76 50 55a 2130a llb 18.8ab 2.2a
102 50 59a 2280a 4c 19.4a 2.4a
Williams 25 47 54a 2760a 12a 19.8a 2.0a
51 50 55a 2610ab 6b 19.6a 1.9a
51t 98t 53a 2520ab Ic 18.9a 1.9a
76 49 57a 2330ab 2c 20.1a 1.9a
102 48 58a 2190b 3c 19.9a 2.0a
* Means in a column within a given cultivar not followed by the same letter
are significantly different at the 0.05 level according to Duncans New
Multiple Range test. 2
t This row spacing treatment seeded at 112 seeds/m ; all other treatments
seeded at 56 seeds/m2.
ttl = Very Good; 5 = Very Poor.











combined total yields of two soybean crops per season were 5270, 4400, and
6210 kg/ha in 1977, 1978, and 1979. In spite of the apparent success of
these experiments, further experimental and farm level evaluation is needed
before the practice is recommended to Florida producers. Careful management
is the key.

LITERATURE CITED

Akhanda, A. M., G. M. Prine, and K. Hinson. 1976. Influence of genotype and
row width on late-planted soybeans in Florida. Proc. Soil & Crop Sci.
Soc. of Florida 35:21-25.
Boote, K. J. 1977. Production potential for early maturing soybean cultivars
planted in March in Florida. Proc. Soil & Crop Sci. Soc. of Florida 36:
152-157.
Boote, K. J. 1980. Response of soybean maturity groups to March planting in
Southern USA. (Submitted to Agronomy J.).
Fehr, W. R., C. E. Caviness, D. T. Burmood, and J. S. Pennington. 1971. Stage
of development descriptions for soybeans, Glycine max. (L.) Merrill. Crop
Sci. 11:929-931.
Fehr, W. R. and C. E. Caviness. 1977. Stages of soybean development. Iowa
State University Cooperative Extension Service Special Report 80.
Gallaher, R. N, M. D. Reed, R. B. Forbes, F. M. Rhoades, and W. T. Scudder.
1979. Corn-soybean succession double cropping. University of Florida,
IFAS, Agronomy Department, Agronomy Fact Sheet No. 93.
Guilarte, T. C., R. E. Perez-Levy, and G. M. Prine. 1975. Some double crop-
ping possibilities under irrigation during the warm season in north and
west Florida. Proc. Soil & Crop Sci. Soc. of Florida 34:138-143.
Hartwig, E. E. 1954. Factors affecting time of planting soybeans in the
Southern States. U.S. Dept. of Agr. Circular No. 943.
Johnson, H. W., H. A. Borthwick, and R. C. Leffel. 1960. Effects of photo-
period and time of planting on rates of development of the soybean in
various stages of the life cycle. Bot. Gaz. 122:77-95.
Lawn, R. J., and D. E. Byth. 1973. Response of soybeans to planting date in
Southeastern Queensland. Influence of photoperiod and temperature on
phasic development patterns. Aust. J. Agr. Res. 24:67-80.
Major, D. J., D. R. Johnson, J. W. Tanner, and I. C. Anderson. 1975. Effects
Sof daylength and temperature on soybean development. Crop Sci. 15:174-179.
Prine, G. M., K. J. Boote, W. R. Ocumpaugh, and A. M. Rezende. 1978. Forage
ahd grain crops planted as a second crop during the warm season in north
and west Florida. Proc. Soil & Crop Sci. Soc. of Florida 37:109-114.
Raper, C. D., Jr., and J. F. Thomas. 1978. Photoperiodic alteration of dry
matter partitioning and seed yield in soybeans. Crop Sci. 18:654-656.
Thomas, J. F., and C. D. Raper, Jr. 1976. Photoperiodic control of seed
filling for soybeans. Crop Sci. 16:667-672.
Whiigham, D. K. 1975. International Soybean Variety Experiment. First report
of results. Univ. of Ill. INTSOY Series No. 8.
Whigham, D. K., and H. C. Minor. 1978. Agronomic characteristics and environ-
mental stress, pp. 77-118. In Norman, A. C. (ed) Soybean Physiology,
Agronomy, and Utilization. Academic Press, New York, 1978.






I


WEED CONTROL PROGRAMS FOR NO-TILLAGE SOYBEANS I

B. J. BRECKE I


Interest among growers in raising two or more crops per year on the same
land area (multicropping) is increasing. One of the most successful such
production systems in the southeastern United States has been double cropp- U
ing soybeans after small grain (2). This system is suited to a wide area of
the southeast where fall seeded small grains are harvested early enough for
soybeans to be planted.

No-tillage planting of the soybeans has contributed to the success of double
cropping because it allows establishment of the soybean crop with the least
delay. This often results in more favorable soil moisture at planting and
allows more time for the soybean crop to mature. Another important advan-
tage in this time of rapidly rising fuel costs is the lower per-acre energy
requirement for no-till compared to conventional planting. No-till also re-
quires less labor and decreases soil erosion (1).

Weed Control Programs

In no-till cropping, as with conventional tillage systems, weeds must be
controlled to obtain maximum crop yields. When soybeans are planted into I
the residue of a previously well managed small grain crop,there are some
advantages from a weed control standpoint. First, any weeds present are
usually small and therefore can be controlled easily with a foliar applied
herbicide. Second, the small grain residue will act as a mulch for the soy- U
beans and aid in preventing weed emergence.

Regardless of mulch effectiveness, however, herbicides are essential for
weed control in no-till soybeans since cultivation is not possible. A
contact-active herbicide will be needed to control any vegetation present
at the time of planting while herbicides with residual (preemergence) ac-
tivity will be needed to prevent further weed infestation. A postemergence
treatment may also be required to control escapes from the preemergence ap-
plication. I

Weed control programs for no-till soybeans have been studied at the Agricul-
tural Research Center, Jay, Florida for the past 4 years. The results of
these studies indicate that, as in conventional tillage systems, a complete
herbicide program is required to control the more troublesome weeds (trade
and common herbicide names are listed in Table 1). The results summarized
in Table 2 show that neither preemergence treatments nor directed postemer-
gence applications alone provide complete weed control in no-till soybeans.
The directed treatments did provide somewhat better control than the pre-
emergence treatments but control was still less than desired.

The results from a 1979 test (Table 3) again show that preemergence applica-
tions were not as effective as desired. However, when a program including
both a preemergence and directed postemergence application was used, excellent
control of both grass and broadleaf weeds was obtained. Examples of such pro-

B. J. Brecke is Assistant Professor of Agronomy (Weed Science), Agricultural
Research Center, Route 3, Box 575, Jay, Florida 32565.

30












grams include Paraquat + Surflan + Lexone preemergence plus either Lexone
+ Butyrac, Lorox + Butyrac, or Paraquat directed postemergence. To obtain
the best results the directed postemergence applications should be made to
soybeans at least 12 inches tall and to weeds less than 3 inches tall. The
spray should not contact more than the lower one-third of the soybean
plant. The addition of a surfactant will improve control.

Conclusions

Though the mulch provided by residue from a small grain crop will aid in
controlling weeds, herbicides are an essential part of a no-till cropping
system, A good herbicide program includes a contact-active material to con-
trol any vegetation present at the time of planting in combination with her-
bicides which provide residual control of both grass and broadleaf weeds. A
directed postemergence application may be required in instances where pre-
emergenice materials do not provide the desired weed control.

References

1. Gallaher, R. N. 1977. Soil moisture conservation and yield of crops
no-till planted in rye. Soil Sci. 41:145-147.

2. Lewis, W. M., and J. A. Phillips. 1976. Double cropping in the eastern
United States. p. 41-50.. In M. Stelly (ed.), Multiple cropping. Amer.
Soc. of Agron., Madison, WI.



Table 1. List of common and trade names
of herbicides described in this paper.


Common name Trade name
Paraquat Paraquat
Metribuzin Sencor or Lexone
Linuron Lorox
Oryzalin Surflan
2,4-DB Butyrac or Butoxone






32 I


I


Table 2. Weed control in no-till soybeans at ARC, Jay, 1976.


Rate When
Treatment lbs/A applied % Control2
a.i. CB TM

Paraquat + Sencor .5 + .5 PRE + PRE 69 69
+ X77 + .25% + PRE

Paraquat + Lasso .5 + 2 PRE + PRE 54 70
+ Lorox + X77 + 1 + .25% + PRE

Paraquat + X77 + .5 + .25% + PRE + PRE 84 88
Sencor + 2,4-DB .38 + .25 + DP + DP

Paraquat + X77 + .5 + .25% + PRE + PRE 74 84
Lorox + Butyrac .5 + .25 + DP + DP


IPRE = Preemergence in the soybeans; DP = directed postemergence.
2CB = Cocklebur; TM = tall morningglory.


Table 3, Weed control programs for no-till soybeans at ARC, Jay, 1979.


Rate When
Treatment lbs/A applied % Weed Control2
a.i. CG TM BW

Paraquat + Dual + .25 + 1.5 + PRE + PRE + 53 80 83
Lexone + X77 .5 + .25% PRE + PRE

Paraquat + Lasso + .25 + 2 + PRE + PRE + 83 80 73
Lexone + X77 .5 + .25% PRE + PRE

Paraquat + Surflan + .25 + 1 + PRE + PRE + 80 53 90
Lexone + X77 .5 + .25% PRE + PRE

Paraquat + Surflan + .25 + 1 + PRE + PRE + 91 100 100
Lexone + X77 + .5 + .25% + PRE + PRE +
Lexone + Butyrac + .5 + .25 + DP + DP +
X77 .25% DP

Paraquat + Surflan + .25 + 1 + PRE + PRE + 95 100 100
Lexone + X77 + .5 + .25% + PRE + PRE +
Paraquat + X77 .25 + .25% DP + DP

Paraquat + Surflan + .25 + 1 + PRE + PRE + 83 95 98
Loxone + X77 + .5 + .25% + PRE + PRE +
Iorox + Butyrac + .5 + .25 + DP + DP +
X77 .25% DP

PR = Preemergence to the soybeans; DP = directed postemergence.
2CC = Crabgrass; TM = tall morningglory; BW = Florida beggarweed.












DEEPER ROOTING IN MINIMUM TILLAGE TO CONSERVE ENERGY


Robert B. Campbell



Conserving energy in the 1980's is more than just reducing fuel or
"petrol" use. We would like to believe a little energy conservation is
essential, preferably by someone else or by some governmental action
that will provide us with labor saving productivity improvements to
maintain the comforts we have become accustomed to. Scientific reality,
however, dictates that quick easy solutions will not be developed
without careful planning for the efficient use of our energy resources
andwithout strong efforts to find and develop new sources of energy.
Because agriculture is the primary source of our food supply, energy
must be considered in relation to the total crop production potential,
i.e. production per petrol dollar spent or production per unit of
energy input.

Reduced tillage defined
No-till farming in concept is directed to lower use of energy for crop
production. Unfortunately the word no-till is misleading, in fact,
no-till is not no till at all. The term has been coined to refer to a
system of residue management. In this system, seeds are drilled into
soil with live or dead plant materials still remaining on the soil
surface. Weeds are mostly controlled by the application of constant or
residual grass and broad leaf herbicides. However, mechanical weed
control is possible under some circumstances. This concept of residue
management has been referred to as eco-fallow (2), minimum till (5), or
conservation tillage (3). These systems require higher levels of soil
and crop management than conventional clean till farming methods.

Advantages and problems in minimum tillage
Often claimed advantages of minimum tillage over conventional
tillage include: lower erosion, water conservation, ability to plant
earlier, planting on steeper less fertile slopes, lower fuel costs, and
lower compaction (5). Minimum tillage methods can be used in multiple
cropping systems (4). Even though these appear to be distinct ad-
vantages, there are disadvantages or special challenges that must be
addressed to make minimum tillage successful. Because minimum tilled
land'is not smooth and open, stands of crops are difficult to esta-
blish. Birds, and rodents are more active because the residue provides
protective cover. Fungi and insects infestations are more common when
residues remain on the surface. The real question is how can these
problems be solved. Most certainly they can be solved, but only with
greater scientific input.

Robert B. Campbell is a Soil Scientist at the USDA-SEA-AR, Coastal Plains
Conservation Research Center, Florence, South Carolina 29502.







34


I
The soil physical system and minimum tillage
Recognizing soil physical and chemical conditions is an essential
part of residue management in different parts of the country. Minimum
till farming in the Southeast has to be accomplished in deep sandy
soils or in sandy loam or loamy sand soils with genetically compact or
mechanically compacted layers (1). These soils also have low water
retentivity, consequently it is just as important to consider deep
rooting and ways of achieving deeper rooting in minimum tillage as in
conventional tillage. Without giving proper attention to these soil
physical conditions, minimum tillage practices would eventually reduce
the production base and actually increase energy use per unit of crop
production. i

In view of the limitations that soil physical conditions may have on
residue management and energy use, corn rooting patterns were studied
in relation to soil strength and soil water availability to corn in a
Norfolk loamy sand soil with a compact A2 horizon. Large acreages of
these soils occur in the Southeast. For example, in Florence County,
South Carolina alone, 58% of the tilled soils have an A layer (1).
Although these layers vary in compactness, they are easily compacted by
tillage tools and wheel traffic.

Describing soil physical parameters I
Soils are never uniform in texture, structure and bulk density. Roots
are not symetrically distributed in soil, therefore, water withdrawal
can not be uniform. Consequently, a mean value and frequency distri- 3
bution of certain properties such as bulk density are frequently used
to describe soil conditions shown in Table 1.

Table 1. Bulk density and related frequency distribution I
for a Norfolk soil at Florence, SC


Bulk Density Relative Frequency %
g/cm3 Ap A2 B

1.25-1.29 10.0
1.30-1.34 4.3 5.0
1.35-1.39 2.1 5.0
1.40-1.44 2.1 5.0
1.45-1.49 8.7 20.0
1.50-1.54 26.1 30.0
1.55-1.59 17.5 20.0
1.60-1.64 8.7 2.9 5.0
1.65-1.69 8.7 7.7
1.70-1.74 17.4 15.4
1.75-1.79 2.2 32.7
1.80-1.84 2.2 38.5
1.85-1.89 1.9
1.90-1.94 0.9

Mean g/cm3 1.57 1.78 1.48
Std. deviation 0.155 0.049 0.099
Schewness -0.0107 -0.2283 -0.7704










The mean bulk density values for the Ap, A and B horizons are 1.57,
1.78, and 1.48 g/cm3, respectively. The wide distribution of the Ap
layer is a result of subsoiling in a minimum tillage experiment in
which/corn was planted into a standing rye cover crop. The subsoil
tool-- produced a narrow slot 10-15-cm wide in the A2 layer that pene-
trated 47 cm, about 5 cm into the B horizon. The Ap bulk density
measurements were more normally distributed about the mean value than
the A2 or B horizons.

Rooting and soil strength
Increasing bulk density increases resistance to rooting but bulk density
is not the only factor that affects rooting because decreasing soil
water content also increases the strength of soil. Therefore, root
penetration is a function of bulk density, water content, and texture.
We have determined that soil probes give a reliable index of roota-
bility in soil, and that a penetrometer index of 20 kg/cm2 represents a
value beyond which few roots penetrate. In the Ap horizon at the mean
bulk density of 1.57 root penetration is severely restricted at a
matric potential of a little over -1000 mb. One could anticipate that
roots would be well distributed throughout the A2 horizon because of
the wide range in the bulk density frequency distribution (see Table
1). In the A2 horizon however, the matric potential at which roots were
restricted was -220 mb at a mean bulk density of 1.78 g/cm3. Root
development observations in a corn field showed that rooting in the A2
horizon occurred only in the subsoiled portion of the A Rooting in
the B horizon was restricted to those roots that extended down the A2
subsoiled soil. The B horizon had the lowest bulk density of all
layers studied, 1.48 g/cm3. Rooting observations demonstrated that
once a root grew through the disturbed A2 horizon, root growth into the
B horizon was only slightly impeded. Because soil strength restricted
robting, soil strength affects water availability. By taking -50 mb as
the upper limit of water availability and the water content corresponding
to 20 kg/cm2 as the lower limit of water availability to the plant, the
amount of water storage for each layer to the 75-cm depth can be calculated.
These calculated water storage values are given in Table 2.

Table 2. Water storage in a 75-cm profile based on
-50 mb and the matric potential water content at 20 kg/cm2
as the upper and lower availability water limits, respectively.
(only the subsoiled protion of the A2 was considered)

Layer Depth Storage
(cm) (cm)
Ap 0-17 2.37
A 17-35 0.30
B 35-75 2.91
Total 5.58



1/ Brown-Harden Superseeder with an attached subsoil tool. Mention of
tradenames is for reference and does not constitute endorsement by USDA
or its cooperators.






36

I
Various assumptions were made for calculating effective soil water
storage. Four examples taking various limiting factors into con- |
sideration are presented in Table 3.
Table 3. Calculated available water storage in a Norfolk loamy
sand profile to depth of 75 cm.


Limiting Condition for Estimating Soil Water Storage
Available Water (cm)
(1) -50 mb and -1000 mb upper and
lower limits 7.1
(2) -50 mb to 20 kg/cm2 strength
(all layers) 6.0
(3) -50 mb to 20 kg/cm2 in (subsoiled
in A2 only) 5.6
(4) -50 mb and -1000 mb in actual
observed rooting volume 4.0

These data show the importance of having roots uniformly distributed
throughout the soil profile and further the necessity of expanding the
volume of rooting in the B horizon. If roots were restricted only to
the A horizon, the effective water availability to the plants would
have been about 43% of that of the subsoiled soil 2.37 vs. 5.58 cm.
These soil water storage calculations do not take into account the
amount of water that would have been provided to the plant by unsaturated
flow for most regions in the soil to the root surfaces.
These data indicate efficient energy use in minimum tillage agriculture
when depth of rooting and methods of offsetting the effects of drought
are taken into account. High crop production insures efficient use of
fuel that has been expended in establishing the crop which is an important
aspect of the energetic of residue management.
References
1. Campbell, R. B., D. C. Reicosky, and C. W. Doty. 1974. Physical
properties and tillage of Paleudults in the southeastern Coastal
Plains. J. Soil and Water Cons. 29:220-224.
2. Fenster, C. R., G. A. Wicks, and D. E. Smika. 1973. The role of
eco-fallow for reducing energy requirements for crop production.
Abstracts American Soc. of Agronomy 64:122.
3. Reicosky, D. C., D. K. Cassel, R. L. Blevins, W. R. Gill, and G. C.
Naderman. 1977. Conservation tillage in the Southeast. J. Soil
and Water Cons. 32:13-19.
4. Sanford, J. 0. 1974. Double crop for more grain. Mississippi Agric,
and Forestry Expt. Sta. Information Sheet #1255.
5. Wells, K. L. May-June 1979. Why No-till. Fertilizer Solutions.
48-62.


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FUEL CONSUMPTION AND POWER REQUIREMENTS
FOR TILLAGE OPERATIONS

Richard P. Cromwell, James M. Stanley,
Raymond N. Gallaher, David L. Wright


It is estimated that well over half of the engine horsepower used on
American farms is for tillage operations. Many of the implements
used, and much of the need for tillage operations have long been taken
for granted. Reducing tillage operations was of considerable inter-
est before the advent of high priced energy, but interest increased
sharply when the price per gallon of fuel jumped to three digits.

Diesel tractors are more efficient than gasoline tractors (a diesel
uses about 70% as much fuel for a given job than a gasoline tractor).
Tractors used to perform tillage operations were some of the first to
use diesel engines because they were relatively high horsepower units
that offered the greatest opportunity to recapture the diesel's higher
initial cost. The transition to diesel is virtually complete today.
Diesel engines are found in the large multi-hundred horsepower land
preparation tractors down to sub-20 horsepower imported tractors. Many
manufacturers of water cooled tractors either do not offer a gasoline
engine powered unit or only prepare one on special order. Therefore,
fuel consumption figures reported in this paper are considering diesel
tractors exclusively.

Most of the published information used for determining farm implement
energy requirements were derived from data gathered in the Midwest.
This data would probably be appropriate for many farm implements, but
energy requirements for tillage implements could be appreciably differ-
ent because of soil type.


Determining Implement Energy Use

Reasonably accurate energy use data can be determined by simply filling
the tank to the top, using the machine over a measured area, and deter-
mining the fuel used by accurately measuring the fuel needed to restore
the level in the tank, if a relatively large area is being worked, the
tractor is on level ground, and the tractor is shook vigorously to expel
air bubbles from the tank.



Richard P. Cromwell, Associate Professor, Agricultural Engineering Depart-
ment; James M. Stanley, Visiting Professor Agricultural Engineering De-
partment; Raymond N. Gallaher, Agsociate Professor, Agronomy Department;
David L. Wright, Assistant Professor, Agronomy Department. Institute of
Food and Agricultural Sciences, University of Florida, Gainesville,
Florida 32611.






38


In order to increase the accuracy of energy use values when working
smaller areas, and,to speed up the operation by eliminating the need for
burping air bubbles from the tank, a plexiglass tube was mounted on the
fuel tank of a tractor as shown in Figure 1 below. This arrangement makes
it possible to get a relatively large fuel level change in the tube when
working smaller areas than would be feasible with the "Tank Refill" method.


FIGURE 1


The first tube that was mounted on the tractor had a 2 inch inside
diameter and would give a large, easily measured fuel level change when
the tractor was used for a short time. However, a small change in the
temperature of the tractor fuel caused a significant change in the fuel
level in the tube. The tube was changed to a 4 inch inside diameter tube
in order to reduce the error induced by fuel volume change.


Results of Implement Energy Requirement Trials

Corn was planted at three different locations in the Gainesville area
beginning in February, 1980. The soil preparation and planting treatments
were as shown below:

1) Disk, moldboard plow, disk, subsoil, plant
2) Disk, moldboard plow, disk, plant
3) Subsoil, plant
4) plant

The energy requirements for these operations were determined using the
"Tank Refill" method. Even though the plot areas were only 0.3 acres to
0.9 acres, which is probably small for determining fuel requirements by
tank refilling, the results given in Table 1 fall in a rather narrow band.
A great amount of credit for this uniformity of results is attributed to
the amount of tractor shaking done to expel air bubbles.








Table 1 Corn Planting Energy Requirements 1

Location Energy Used Per Operation (Gallons/Acre)

Plot First Plowing Second Subsoil and Plant
Number Disking Disking Plant

1 0.54 1.63 0.75 1.53 -

2 0.64

3 0.41 1.40 0.65 0.83

Gainesville 4 1.39 -

5 0.53 1.43 0.61 0.77

6 0.53 1.50 0.50 1.31 -

7 1.23 -

8 0.64

1 0.56 1.27 0.63 1.19

2 0.74

3 0.51 1.47 0.53 0.86

Newberry 4 1.24 -

5 0.51 1.42 0.60 0.85

6 0.51 1.36 0.60 1.31 -

7 1.27

8 .076

1 0.58 1.40 0.67 1.32 -

2 0.73

3 0.51 1.35 0.62 0.87

Chiefland 4 1.44 -

5 0.49 1.34 0.57 0.87

6 0.49 1.33 0.60 1.32 -

7 1.44 -

8 0.73






40 1


The equipment used to perform the soil preparation and planting op-
erations were: an eight foot wide tandem disk, a 3 bottom plow that cut
approximately a 4 foot-6 inch slice, a two row Brown-Harden no-till planter
with subsoiling shanks, a two row Brown-Harden no-till planter without sub-
soiling shanks, two sets of unit planters for mounting on the two no-till
units, a 52 horsepower tractor, and a 58 horsepower tractor. 3

The data indicates that at all locations the initial disking required
approximately 0.5 gallons per acre. The moldboard plowing required approx-
imately 1.40 gallons per acre. The second disking required approximately
0.6 gallons per acre'of 0.1 gallons per acre more than the initial disking
because of more slippage. The no-till planter equipped with the subsoiler
shanks required about 1.30 gallons per acre. When the no-till planter did
not have subsoiling shanks approximately 0.75 gallons per acre was used
for planting. Subtracting the no subsoiling from the subsoiling figures
indicates that approximately 0.55 gallons per acre were required for the
subsoiling operation.

Tests were also conducted at the Agricultural Experiment Station in
Quincy, Florida to determine the energy requirements for some tillage op-
erations in heavier soil than those found in the Gainesville area. The
results are shown in Table 2.


Table 2 Tillage Energy Requirements, Quincy

Operation Depth of Cut (inches) Gallons/Acre

Tandem disk 5 0.66

Offset disk 6-7 0.96

Rolling cultivator shallow 0.36


I
The tandem disking operation was performed by a 12 foot wide unit with
20 inch scalloped disks drawn by an 85 horsepower tractor. The offset disk
was a 7 foot wide unit with 20 inch scalloped disks drawn by a 52 horsepower
tractor. The rolling cultivator was a 4 row unit drawn by a 150 horsepower
tractor. I

Comparison with Other Published Data

The following is a comparison of the tillage energy requirements pub-
lished by Iowa State University and those recently determined in Florida.










Field Operation Gallons/Acre
Iowa Florida

Moldboard plow 1.90 1.40
Offset disk 0.95 0.96
Tandem disk 0.45 0.50
Rolling cultivate 0.40 0.36



How Might Energy Requirements Be Reduced

Farmers cannot use tractor engine efficiency as the sole guide for de-
terming what tractor to buy because of practical considerations like dealer
location and dealer's ability to provide parts and service. However, it is
felt that more thought should be given to engine efficiency in order to re-
duce energy requirements. The results of the Nebraska Tractor Tests conducted
over the last 10 years reveal that the 24 most efficient tractors delivered
13.91 horsepower hours per gallon while the 24 least efficient tractors de-
livered 11.16 horsepower hours per gallon. This is a difference of 24.6%
and farmers must be made more aware of how to use Nebraska Test Data.






I


I
HERBICIDE TOLERANCE AND WILD RADISH CONTROL
IN LUPINE AND VETCH

G.R. England, W.L. Currey, and R.N. Gallaher

INTRODUCTION

Wild radish (Raphanus raphanistrum Crantz) is a common weed in grain I
crops throughout the world. Wild radish is a self pollinated annual
found mainly in cereals, fallows, and non-crop areas. In Florida it
grows as a winter annual in these sites. It is a moderate to vigorous
competitor for space.

Extensive work in the control of this weed has been done in Germany,
the Soviet Union, and Great Britan. Research has been carried out
world wide on the control of wild radish in numerous crops, using
many herbicides. In Brazil, wild radish was controlled with 2, 4-D
applied by air (Guibert, 1972). Merich et al. (1972) found BAS 3580H I
(bentazon 26% and dichloroprop 34%) and BAS 3960H (bentazon 25% and
mecoprop 37.5%) controlled wild radish, Chrysanthamum segetum, Cusicim
spp., Galum aparine, Matricaria sp., and Sinapsis arvensis. Hahn (1973) I
controlled wild radish in grasses with SYS 67ME (MCPA 86% free acid) at
1.5 kg/ha and SYS 67 Prop (dichloroprop potassium 64% acid). Koboreva
(1971) controlled wild radish in buckwheat (Fagopyrum tataricum) with
1-2 kg/ha 2, 4-D amine. Treating with MCPA (1-2 kg/ha) or norea (0.5 kg/ha) I
increased yields of buckwheat by 1000 kg/ha. Osususka et al. (1973)
gained twice the control of wild radish compared to the check with 0.25 i
kg/ha of atrazine. Cochet et al. (1973) obtained control with Phyt
3425 (chlormtofen 20% + linuron 5%) at 1.85-5.0 kg/ha. Huggenburger et
al. (1974) obtained control of wild radish, Digitaria singuevalis,
Amaranthus sp., Polygonium spp.,. and Sinapsis arvensis with oryzalin
1.0-1.4 kg/ha + linuron (1.0-1.4 kg/ha) applied surface preemergence with
12.5 mm precipitation n r shallow incorporation. Hermant et al. (1973)
treated 4 cm flax (Linum usitatissimum) and R. raphanistrumm) in an early
stage with bentazon and achieved good weed control with no injury to the I
flax. Detrernix et al. (1973) achieved control of Raphanus with alachlor
(1.7-2.0 kg/ha) or propachlor (0.5 kg/ha) applied preemergence. Leiderman
et al. (1972) controlled wild radish with oxadiazon (1.5-2.0 kg/ha).
Amaranthus vidis, Galingosa parviflora, and Digitaria sanguinalis were
also controlled.

Wild radish is a problem in winter forage crops at the Robinson Farm in
Williston, Florida. Since this problem weed existed in land already
utilized for research, the following experiment was established to determine
possible control measures that could be utilized to control wild radish
in lupine, Lupinus angustifolia, and vetch (Vicia villosa).

G.R. England, W.L. Currey, and R.N. Gallaher are Weed Science Graduate 3
Student, and Associate Professors, Agronomy Department, Institute of Food
and Agricultural Sciences, University of Florida, Gainesville, Florida 32611.

42

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MATERIALS AND METHODS

The experiment was conducted at the Robinson Farm in Williston, Florida
during the winter of 1979-1980. Wild radish control was evaluated in
lupine and vetch which were planted behind several no-tillage operations.
The land was harrowed three times and then "Hairy vetch" (33.6 kg/ha)
and "Frost lupine" (89.6 kg/ha) were properly inoculated and drilled on
November 1, 1979. Lupine was irrigated (3.2 cm) on November 9, 1979
and vetch was irrigated on November 10. A portion of both lupine and
vetch received an application of bentazon (1.12 kg/ha) on January 3,
1980. The bentazon was applied in a 280 1/ha spray at 2.8 kg/'cmz.

On January 15, 1980, three chemicals, acifluorfen (Blazer), bentazon
(Basagran), and 2, 4-DB (Butyrac) were applied postemergence to vetch
and lupine.

Herbicides Rate
acifluorfen 0.28, 0.43, 0.56
bentazon 0.84, 1.12
2, 4-DB 0.28, 0.56

AG-98 at 0.25% v/v was added to acifluorfen. Two applications of each
chemical were made to lupine and vetch which had been previously treated
with 1.12 kg/ha bentazon and to plots not previously treated. The major
weed to be studied was wild radish.

The herbicides were applied with a CO2 backpack plot sprayer in 187 1/ha
spray at 3.36 kg/cm2 on January 15, 1980. The second application of
acifluorfen and bentazon was made on January 28, 1980 to wild radish
plants that were 61 cm high. The second application of 2, 4-DB was made
on February 3, 1980. The same method of application was used.

Each experiment was set up in a randomized complete black design and 4
replications were used. The treatments were rated by 4 visual observa-
tions for crop tolerance and wild radish control. A rating of 0 equals
no affect on the crop or the weed, while a rating of 10 equals complete
control of either the crop or the weed.


RESULTS AND DISCUSSION

In the four visual ratings there were significant differences between
both weed control and crop tolerance (Tables 1. 2. 3, 4). By the fourth
rating, acifluorfen and bentazon had provided almost complete wild radish
control at all rates. Acifluorfen had caused from moderate to severe
crop injury in vetch and severe crop injury in lupine. Bentazon caused
no crop injury in vetch but almost completely removed the lupine.

Bentazon provided good wild radish control in both crops. There was
excellent crop tolerance in vetch, but no crop tolerance of bentazon in
lupine. Acifluorfen provided comparable weed control to bentazon. There
was some tolerance of vetch at the low rate.







44 1


2, 4-DB, due to the advanced stage of growth of WR at application,
provided no wild radish control. It caused slight crop injury in
both vetch and lupine. In vetch it caused leaf curl and in lupine
it caused the stem to curl.

The timing of application was not optimum for control with selective
herbicides. It is significant that good control of the weed by benta- U
zon and acifluorfen was obtained in this stage of growth.

There seemed to be an interaction with bentazon and temperature. Con- I
trol of wild radish appeared to be enhanced by hard freezes after ap-
plication. This was observed at Williston and in wild radish treated
with 0.84 kg/ha basagran at the Green Acres research farm.

Bentazon has been shown to be affected by environmental factors (BASF
Tech. Info., Bull. No 7804). An optimum temperature for bentazon
would be over 18 C (Ellison, 1980). This temperature relationship I
would have to be considered when determining a control program for a
winter weed, since winter temperatures in Florida vary so much. -

This experiment should be repeated to observe the activity of these
chemicals on the crop and weed, in an earlier growth stage. The affects
of temperature on bentazon need to be evaluated further. I


REFERENCES

1. Cochet, J.C., Pavot, J., Butler, A., Devidal, R., Bouchan, F. 1973.
A study of recent pre and post emergence herbicides in soft winter
wheat. Weed Abstracts 1975.
2. Detrernix, L., Kaqrenne, W. 1973. Consideration on 3 years herbicide
trials in winter rape crops. Weed Abstracts 1975.
3. Ellison, E. 1980. Personal communication.
4. Guibert. 1972. Agricultural Aviation in Brazil. Agric. Aviat. 14(3) I
76-81.
5. Hahn, E. 1973. Experience in the use of herbicides on newly sewn i
grasslands. Weed Abstracts 1973.
6. Hermant, P., Beardin, X., Noivel, M., Serna, G., Lutanid, G., Lipatoff,
V. 1973. Bentazone for the control of broadleaf weeds in flax. Weed
Abstracts 1975. 3
7. Huggenburger, F., Saipe, N., Lesniuc, 0. 1974. Oryzalin plus linuron,
a new herbicide combination for pre emergence weed control in soybeans.
Weed Abstracts 1974.
8. Koloreva, A.A. 1971. The use of herbicides for weeding buckwheat. I
Weed Abstracts 1974.
9. Merick, B.H.,Behrendt, S. 1972. Trials in cereals with bentazon (3-
isopropyl l-lh-2, 1, 3-benzothiadiazin) in combination with hormones I
(BAS 3580H and BAS 3960H). In Proc 14th British Weed Control Conference.
British Crop Protection Conference. 666-672.
10. Leiderman, L., Grassi, N. 1972. A trial with 3 new pre emergence her-
hicides in carrots (Dawius carota). Weed Abstracts 1976.
11. Osuskaya, T.V. 1973. Herbicide phytotoxicity and activity in relation-
Ship to nutrient level of plants. Weed Abstracts 1974. I



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TABLE 1. Control of Wild Radish and Vetch Tolerance From the Use
of Herbicides Following an Application of 1.12 kg/ha
Bentazon.

Date
Treatment 1-26-80 2-3-80 2-7-80 2-14-80

Wild Radish Control

acifluorfen 6.0 a 8.5 a 9.9 a 9.9 a
bentazon 4.5 a 8.0 a 9.5 b 9.7 a
2,4-DB 1.0 b 1.0 b 1.0 c 1.0 b
check 1.0 b 0.0 b 1.0 c 1.0 b

Crop Tolerance

acifluorfen 2.5 a 5.5 a 6.5 a 6.5 a
bentazon 0.0 a 0.5 c 2.0 b 0.0 c
2,4-DB 0.0 a 2.0 b 0.0 b 3.0 b
check 0.0 a 0.5 c 0.0 b 0.0 c

A rating of 0 equals no affect on the crop or weed, while a rating of
10 equals complete control of either the crop or the weed.

Values among treatments within each date followed by the same letter
are not significantly different at the 0.05 level of probability ac-
cording to Duncan's new multiple range test.





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TABLE 2. Control of Wild Radish and Vetch Tolerance From the Use of
Herbicides With No Previous Herbicide Application.

Date
Treatment 1-26-80 2-3-80 2-7-80 2-14-80
Wild Radish Control
acifluorfen 3.5 a 4.5 b 6.5 a 7.0 b
bentazon 1.5 b 6.0 a 8.5 a 8.25 a
2,4-DB 0.0 b 0.0 c 0.5 b 0.0 c
check 0.0 b 0.0 c 0.0 b 0.0 c
Crop Tolerance
acifluorfen 3.0 a 4.0 a 5.5 a 4.5 a
bentazon 0.0 b 0.5 b 0.0 b 0.0 c
2,4-DB 0.0 b 2.5 ab 2.0 b 2.0 b
check 0.0 b 0.0 b 0.0 b 0.0 c
A rating of 0 equals no affect on the crop or weed, while a rating of
10 equals complete control of either the crop or the weed.
Values among treatments within each date followed by the same letter ,
are not significantly different at the 0.05 level of probability ac-
cording to Duncan's new multiple range test. I



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TABLE 3. Control of Wild Radish and Lupine Tolerance from the Use of
Herbicides Following an Application of 1.12 kg/ha Bentazon.




Date
Treatment 1-26-80 2-3-80 2-7-80 2-14-80

Wild Radish Control
acifluorfen 4.0 a 7.5 a 9.25 a 9.7 a
bentazon 2.0 b 8.0 a 9.25 a 9.5 a
2,4-DB 1.0 bc 1.0 b 1.0 b 1.5 b
check 0.5 c 1.0 b 1.0 b 1.0 b
Crop Tolerance
acifluorfen 8.0 a 9.45 a 9.9 a 9.9 a
henta?on 10.0 a 9.95 a 9.9 a 9.9 a
2,4-DB 2.0 b 5.0 b 4.0 b 2.5 b
check 0.0 b 0.5 c 2.0 b 2.0 b

A rating of 0 equals no affect on the crop or weed, while a rating of
10 equals complete control of either the crop or the weed.

Values among treatments within each date followed by the same letter
are not significantly different at the 0.05 level of probability accord-
ing to Duncan's new multiple range test.





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TABLE 4. Control of Wild Radish and Lupine Tolerance From the Use
of Herbicides Following No Previous Herbicide Application.
Date
Treatment 1-26-80 2-3-80 2-7-80 2-14-80
Wild Radish Control
acifluorfen 3.0 a 4.5 a 6.5 b 8.25 a
bentazon 1.0 b 6.0 a 8.0 a 8.75 a
2,4-DB 0.56 b 0.0 b 0.0 c 0.0 b
check 0.0 b 0.0 b 0.0 c 0.0 b
Crop Tolerance
acifluorfen .0a a Ibb a
bentazonb b
2,4-DB 5.
check 0.5 b 0.5 b 0.0 d 0.0 b
check
A rating of 0 equals no affect on the crop or weed, while a rating of
10 equals complete control of either the crop or the weed.
Values among treatments within each date followed by the same letter
are not significantly different at the 0.05 level of probability accord-
ing to Duncan's new multiple range test.
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WEED CONTROL FOR NO-TILLAGE SOYBEANS IN RYE STRAW


RAYMOND N. GALLAHER AND WAYNE L. CURREY


INTRODUCTION

Soybean (Glycine Max L. Merr.) is an important cash crop to Florida agri-
culture. In recent years acreage has steadily increased and is expected
to be over 500,000 acres by 1985. This crop has a potential gross value
of over 100 million dollars annually, adding significantly to Florida's
economy. Most of Florida's soybean crop is planted succeeding other crops
such as small grains, vegetables, and corn in multiple cropping systems.

Significant acreage of small grains grown for grain is produced in Florida.
Soybeans is an ideal crop to succeed small grain in a succession double
croppihg system. Past experience shows that no-tillage planting of soy-
beans into small grain straw can have advantages as compared to conventional
tillage management. Some of these advantages include: 1) Elimination of
tillage for seedbed preparation, thus conserving time, fuel cost, and
equipment, and (2) Conservation of soil and water due to ground cover from
the straw.

Weed control in no-tillage soybeans planted into small grain straw can often
get out of hand if proper herbicides and timing of herbicide application are
not managed properly. Weeds probably cause the greatest yield loss and is
the most devastating pest encountered in soybean farming irrespective of
tillage regime. The objective of this study was to investigate herbicides
and no-tillage management variables for control of weeds and treatment
influence on yield of soybeans planted in rye straw.

MATERIALS AND METHODS

This study was conducted from 1977 through 1979 at the Green Acres Agronomy
farm near Gainesville, Florida. Cobb soybeans were planted into rye straw
in late May using a Brown Harden Superseeder minimum tillage planter. Soy-
beans were seeded in 30 inch rows at 12 seed per foot. Main treatments were
no-tillage in-row subsoil versus no-tillage coulter slot-planting. Four
sub-treatments were herbicide combinations as shown under Tables 1 and 2.
The test was replicated three times. All plots received .25 pounds a.i.
paraquat plus 1 pint Ortho x 77 per 100 gallons of water applied post
directed when the crop was 14 to 18 inches in height.

Weed populations were estimated at harvest each year and are reported as
percentage of the ground covered by weeds. No ground cover of weeds would
represent 0% while complete ground cover would represent 100%.


Raymond N. Gallaher and Wayne L. Currey are Associate Professors of
Agronomy, Department of Agronomy, Institute of Food and Agricultural
Sciences, University of Florida, Gainesville, FL 32611






50 I


RESULTS AND DISCUSSION
Yield I

Soybean yield was considerably higher than the Florida state average
(Table 1). No-tillage coulter slot-planting gave the highest yield
in 1977 as compared to no-tillage in-row subsoil. Weather conditions I
in 1977 were such that severe moisture stress occurred all over Florida.
Several sources indicated that sufficient rainfall did not occur to seal g
up the subsoil slots in 1977 and instead of obtaining better soil moisture I
utilization, the reverse occurred. No data is available to substantiate
this hypothesis, however, the open slot may have caused soil moisture
to evaporate and be lost more easily. Main plot treatments had no
affect on yield in 1978 or 1979.

Herbicide treatments had no affect on yield of soybeans in 1977. The
area was in bahiagrass (Paspalum Notatum Flugge Var,) sod and was destroyed W
by tillage in 1976. Weeds were not a big problem in 1977 as in subsequent
years. Also bahiagrass reestablishment and competition did not become I
significant until after the first year. These combined factors are |
through to be the reasons for all herbicides resulting in similar yield
of soybeans in 1977.
A definite trend emerged among herbicide variables in 1978 and 1979.
The best treatment (alachlor + metribuzin + glyphosate) gave a three-
year average of 37 bu/A. This was a six bu/A advantage over using
glyphosate alone, which resulted in the lowest yield. Applications 3
of oryzalin + metribuzin + paraquat and prodiamine + metribuzin +
paraquat were not statistically different in yield from alachlor +
metribuzin + glyphosate.
Ground Cover of Weeds
The percentage ground cover of weeds at harvest time (Table 2) shows i
a strong relationship with yield. As yield increased weed cover de-
creased. Note that weed pressure was much greater where glyphosate
was used alone. All other treatments had the same ground cover of |
weeds at harvest. This differences was due to residual herbicides
used in the first three treatments but not in treatment four.

If the three year average yield in Table 1 is plotted against the three
year average percentage ground cover of weeds in Table 2 then we obtain
a simple change relationship given by the following equation: yield =
38 bushels .23(x change in percent ground cover of weeds). This means
that soybean yield was reduced by 0.23 bu/A as the percent ground cover
of weeds increased by 1%. If there had been no weeds, yield should have
been 38 bu/A, If there had been 30% ground cover of weeds, yield pre- 3
diction would be 38 bushels .23(30%) or 31 bu/A.

Summary I
With proper management, no-tillage soybeans in rye straw can be grown
successfully. Proper selections and timing of herbicides are critical
for successful weed control in no-tillage soybeans. This study shows

I






51


that alachlor + metribuzin + glyphosate provided good overall yield and
the least competing weeds. Other treatments, using residual herbicides
and the :contact herbicide- paraquat were statistically equal in yield
and ir weed control to the above treatment. Soybean yield was reduced
by almost 1/4 bu/A for each percentage increase in ground cover of weeds.





52

Table 1. Yield as affected by subsoiling and chemical weed control for minimum tillage
soybeans.


1977


1978


1979


3-Year Average


Sub-
Coul. X Soil


Sub-
Coul. X Soil


Sub-
Coul. X Soil Coul,


---------------------------- ercent-- ------------------------


41 46 40a


34 32 33a 38 31 35a 37 36 37a


33 47 44a 32 28 30ab 31 31 31ab 32 35 34ab I


37 43 40a 30 28 29ab 31


31 31ab 32


34 33ab


37 41 39a 29 27 28 b 26 29 28 b 30 32 31 b


31 29NS


32 31NS


33 34NS


tl. Alachlor (Lasso) 3 lb. a.i./A + Metribuzin (Sencor 50WP) 0.38 lb a.i./A +
glyphosate (Roundup) 2 lb a.i./A.
2. Oryzalin (Surflan 75W) 1 lb. a.i./A + Metribuzin (Sencor 50WP) 0.38 Ib/A a.i. +
paraquat (Ortho Paraquat CL) .5 lb a.i./A + Ortho X-77 added at 1 pt/100 gal, spray.
3. Prodiamine (Rydex) 0.33 lb a.i./A + Metribuzin (Sencor 50WP) .38 lb a,i./A +
paraquat (Ortho Paraquat CL) .5 lb a.i./A + Ortho X-77 added at 1 pt/100 gal. spray.
4. Glyphosate (Roundup) 2 lb a.i./A.

+Significant difference between tillage means at 0,05 level of probability,

Means followed by common letters in the same column;are non significant at the 0,05
level of probability.

NS =,Non-significant


Alachlor -
Metribuzin
Glyphosate
Oryzalin -
Paraquat -
Prodiamine


2-chloro-2',6'-diethyl-N-(methoxymethyl)acetanilide
- 4-amino-6-tert-butyl-3-(methylthio)-as-triazin-5(4H)one
- N(phosphonemethyl)glycine
3,5-dinitro-N4,N4-dipropylsulfanilamide
1,1'-dimethyl-4 4' bipyridinium ion
- 2,4-dinitro-N ,N3-dipropyl-6-(trifluoromethyl)-1,3-benzenediamine


Treatment


Sub-
Soil


37 44T







Table 2. Percent ground cover of weeds at harvest of minimum tillage as affected
by tillage and chemical weed control.


I

I Treatment

I I
1.
S 2.




I x3

I 1.

2.
I 3.
S 4.

Mear
0.0
0I NS

I

I

I

I


1977
Sub-
Soil Coul. X


1978
Sub-
Soil Coul.


1979
Sub-
Soil Coul. X


3-Year Average
Sub-
Soil Coul. X


27.8 19.6NS


27.7 29.7NS


12.2 18.2NS


22,7 18.9NS


Alachlor (Lasso) 3 lb. a.i./A + Metribuzin (Sencor 50WP) .38 Ib a.i./A +
glyphosate (Roundup) 2 lb a.i./A.
Oryzalin (Surflan 75W) 1 Ib a.i./A + Metribuzin (Sencor 50WP) .38 Ib a.i./A +
paraquat (Ortho Paraquat CL) .5 a.i./A + Ortho X-77 added at 1 pt/100 gal. spray.
Prodiamine (Rydex) .33 Ib a.i./A + Metribuzin (Sencor 50WP) .38 Ib a.i./A +
paraquat (Ortho Paraquat CL) .5 a.i./A + Ortho X-77 added at 1 pt/100 gal. spray.
Glyphosate (Roundup) 2 Ib a.i./A.

is followed by common letters in the same column are non significant at the
5 level of probability.
SNon Significant


-----~--~-----I-------~--'-~`


---------------percent---------- --------------------
21.3 11.3 16.3 b 12.0 14.0 13.0 b 6.8 12.5 9.7a 13.5 13.8 13.21
25.8! 17.0 21.4 b 15.3 13.0 14.2 b 16.0 18.8 17.4a 19.3 16.3 17.81
22.51 23.8 23.2 b 22.0 12.0 17.0 b 11.3 18.8 15.1a 18,8 18.3 18.6t
41.3 26.3 33.8a 61.3 43.8 52.6a 14.5 22.5 18.5a 39.0 28.3 33.7a






I


I
SUBSOILING AND MINIMUM TILLAGE OF CORN ON
FLORIDA FLATWOOD SOIL ,

R.N. Gallaher and W.R. Ocumpaugh


INTRODUCTION I

Establishing corn (Zea mays L.) in unprepared seedbeds is becoming
a widely practiced management procedure. Minimum or no-tillage plant- I
ing of corn can significantly reduce fuel use and the time required
to plant when compared to conventional tillage management. Florida
has a widely diverse number of soil types, some of which have pro-
duced greater corn yield after in-row subsoiling when compared to a
check. Florida flatwood soils are extensive and data on subsoiling
and minimum tillage on these soils are lacking. This paper provides
and discusses corn data as influenced by tillage on three Florida
flatwood sites in 1979. The soil at all locations was a Pomona sand
(sandy, siliceous, hyperthermic Ultic Haplaquods) having less than
one percent slope.

EXPERIMENTAL PROCEDURE

Three experiments were established in 1979 on soils classified as
Pomona sand. These studies were either on or adjacent to the Beef
Research Unit of the Institute of Food and Agricultural Sciences,
University of Florida, located about 19 km (12 miles) North of
Gainesville. All experiments had two corn hybrids ('DeKalb XL78' and
'Asgrow RXll4') as whole plots and in-row subsoiling versus no sub-
soiling as sub plots. Each was replicated three times. Tillage and
planting operations were accomplished with 4600 and 5600 Ford trac-
tors. Brown-Harden two row Superseeder frames were used for planting,
one with and one without in-row subsoilers attached. Individual
planters were John Deere Flexi 71 units attached to the frame.

In a single pass, corn was seeded in 76.2 cm (30 inches) wide rows at
74,130 seed/ha (30,000 seed/A) with 2.24 kg/ha (2 pound/A) active in-
gredient (a.i.) alachlor (Lasso) (2-chloro-2', 6'-diethyl-N-(meth-
oxymethyl) acentanilide), 2.24 kg/ha (2 pounds/A) a.i. atrazine (2-
chloro-4-ethylamino-6-isopropyl-amino-l, 3, 5-triazine) and 2.24 kg/ha
(2 pounds/A) a.i. carbofuran (Furadan) (2, 3-Dihydro-2, 2-dimethyl-7-
benzofuranyl methylcarbamate). Corn on minimum tillage experiments
also received in the herbicide tank mix 0.56 kg/ha (0.50 pounds/A) a.i.
paraquat plus 0.47 L (1 pint) Ortho X77 surfactant per 378.4 L (100
gallons) of water applied. The herbicides were applied using 8004 tips
spaced 50.8 cm (20 inches) apart at 2.812 kg/cm (40 psi) pressure in
a liquid solution of 113.52 L/ha (30 gallons/A) using water as a carrier.


R.N. Gallaher and W.R. Ocumpaugh are Associate and Assistant Professors 3
of Agronomy respectively, Agronomy Department, IFAS, University of
Florida, Gainesville, Florida 32611.
The use of product trade names does not constitute a guarantee or warran-
ty of the products named and does not signify approval to the exclusion of
similar products.

54 I










Experiment one

Land preparation for experiment one included a harrow (2.44 meter
8 foot bushog) operation followed by a moldboard plow (Ford with three
40.6,cm (16 inch) plows) operation on recently cleared land. We then
broadcast 56-43.4-232.6-33.6-28 kg/ha (50-38.7-207.5-30-25 pounds/A)
of N(nitrogen), P(phosphorous), K(potassium), Frit 503 trace elements
and Mg(magnesium), respectively and harrowed once more on March 16 prior
to planting on March 17. Plot size consisted of eight rows 76.2 meters
(250 feet) long. A 23.2 sq meter (250 sq feet) area was sampled from
each plot for yield determination on July 6, 1979.

Experiment two

This area had been in corn production in 1977 but was not farmed in 1978.
In November of 1978 a light harrow was run over the test site but young
blackberry (Rubus sp.) and other weeds were extensive when corn was plant-
ed by the minimum tillage procedures on March 17, 1979. Fertilizer was
applied at planting in a 20 cm (8 inch) band over the top of the corn row
at a rate of 31.4-27-78.2 kg/ha (28-24-69.7 pounds/A) N, P, and K, res-
pectively. The plots were 6 rows wide and 30.48 meters (100 feet) in
length. A 9.29 sq meter (100 sq feet) area was sampled from each plot
for yield determination .on July 6, 1979.

Experiment three

This area was adjacent to experiment two and had the same cropping history.
This area was undisturbed, in that it had not been harrowed the previous
fall as was the case in experiment two. It was covered with large fruit
bearing blackberry briars and covered uniformly with other broadleaf and
grassy weeds. Treatment and sampling was the same as for experiment two,
however, plot length was 15.24 meters (50 feet) instead of 30.48 meters
(100 feet) as for experiment two. Plots were sampled for yield deter-
mination on July 9, 1979.

Common practices

Procedures common to all studies included the sidedress application of
168 kg N/ha (150 pounds/A) when corn was 50 cm (20 inches) in height.
Near the same time a post direct application of 0.28 kg/ha a.i. paraquat
plus 1.121 kg/ha a.i. linuron (Lorox) (3-(3, 4-Dichlorophenyl)-l-methoxy
1-methyl-urea) and 0.47 L (1 pint) Ortho X77 surfactant per 378.4 L (100
gallons of water was made on minimum tillage experiments. Post direct
herbicide treatments were not needed on experiment one because of low
weed populations associated with the recently cleared land.

Plot weights of whole plants and ears were taken for dry matter, mois-
ture and shelling percent using routine procedures. Forage yields are
reported at zero moisture on a dry matter basis and grain adjusted to
15.5%.

Statistical analyses were made using taped programs for a split plot on
a programmable calculator. Means were evaluated by F test.






56 I



RESULTS AND DISCUSSION I

Data are given in tables 1 through 3 for yield and other variables.
We have indicated treatment differences at the 80% level of probab- B
ility and above. The 80% level was chosen due to the difficulty of
measuring treatment difference with a small number of replications
and treatments.

Both hybrids responded to subsoiling for forage yield in all experi-
ments. This was not the case for grain yield. DeKalb XL78 did not
respond in experiment two and neither hybrid responded to subsoiling
in experiment three. Grain yield was positively related to ear weight
and ear weight was larger in the two minimum tillage experiments,
(Tables 2 and 3) as compared to the conventional tillage test (Table 1). I
This was as expected since it has been shown that more soil moisture
is available to corn if grown under minimum tillage as compared to g
conventional tillage. Since subsoiling also resulted in higher yield
it can be assumed that this also was beneficial in moisture conserva-
tion and possibly better plant root distribution into the subsoil lay-
ers.

Subsoiling had the greatest benefit for corn in the conventional til-
lage study (Table 1). More soil moisture would be lost as a result
of extra soil exposure for evaporation and lack of ground cover to B
reduce runoff and infiltration in the conventional tillage area. The
greater response to subsoiling in experiment one indicated a greater
need for subsoil water as compared to the no-tillage studies.

Yields in the no-tillage experiments were equal to or greater than in
the conventional tillage test. Most inputs were equal except for the
extra fertilizer used and extra fuel consumption, and time required
to prepare the land for planting in experiment one. Specific fuel con-
sumption and time measurements for various operations have not been
made for a Pomona sand but have been measured for other Florida soils. I
Using average values for fuel consumption and time measures for Florida
sandy soils show that the various tillage regimes used in these studies g
vary widely as follows: (1) Conventional tillage soil preparation and
planting would use an average of 34.78 L/ha (3.72 gallons/A) of diesel
fuel and would take 241.91 min/ha (97.9 min/A) to perform. (2) Plant-
ing with in-row subsoiling into the conventional tillage seedbed would
add 5.05 L/ha (.54 gallons/A) fuel used and would require additional
time of 12.36 min/ha (5.0 min/A). (3) No-tillage would reduce fuel
and time requirements tremendously. No-tillage without subsoiling re-
quired an average of 6.55 L/ha (.70 gallons/A) diesel fuel and 77.59 I
min/ha (31.4 min/A) to plant. (4) No-tillage with in-row subsoiling
would add 6.45 L/ha (.69 gallons/A) diesel fuel used and 9.43 min/ha
(41 min/A) time to plant corn.

From the fuel and time data given we can note the following: (1) To
grow corn as in experiment one (non-subsoiled) it would require five
times more fuel than no-tillage (non-subsoiled) as in experiments two B
and three, (2) it would take over three times more time to establish
the crop in the conventional versus no-tillage system, and (3) it would
take twice the fuel of that required for no-tillage to plant with in- I
row subsoiling, but would require only slightly more time to subsoil.

I










If farmers can obtain yields from no-tillage on flatwood soils as
we obtained in these studies, significant savings in energy, equip-
ment, and labor will result in Florida agriculture. At the same time
profits would be higher because of these reduced input costs as well
as the extra returns generated from higher yields that would likely
occur.

An additional factor that needs to be considered on flatwood soils is
that if heavy rains come after the soil has been cultivated (harrowed
and/or moldboard plowed) it can become so wet during the planting sea-
son that it may delay planting. The cultivated soil when wet will not
support machinery. This is not a serious problem in minimum tillage
situations. Thus in wet years planting time could be delayed from a
few days to a few weeks under conventional tillage. Delayed planting
often results in reduced yields. Worse still would be to have the
soil tilled and the fertilizer cultivated in, ready to plant then get
heavy rain that delayed planting two weeks or more as happened at the
Beef Research Unit in 1980. No measurements were made, but undoubted-
ly, considerable N and K fertilizer was lost due to leaching.






58 I


Table 1. Corn Variables as influenced by subsoiling and corn
hybrids grown on a flatwood soil in a conventional tillage seed-
bed, Gainesville, Florida, 1979. (Exp. 1).

Subsoil Subsoil

Variety Yes No Mean Yes No Mean

Dry forage yield kg/ha Grain yield kg/ha
DeKalb XL78 18,699 15,993 17,346a 7,044a 6,755a+ 6,900
Asgrow RX114 18,650 15,890 17,270a 6,077a 4,708a+ 5,393

Mean 18,675 15,942* 6,561 5,732**

Percentage grain in forage Ear weight in grams
DeKalb XL78 31.8a 32.1aNS 32.0 134 103 119a
Asgrow RX114 30.6a 25.0b* 27.8 130 87 109a

Mean 31.2 28.6 132 95**

Number plants/ha Number ears/ha
DeKalb XL78 57,564 56,531 57,048b 52,828 58,856 55,842a
Asgrow RX114 59,717 65,314 62,516a 52,225 54,378 53,381a

Mean 58,641 60,923NS 52,527 56,617*

Plant height in cm Ear node height in cm
DeKalb XL78 251a 259aNS 255 81 86 84b
Asgrow RX114 265a 239b++ 252 91 98 95a

Mean 258 249 86 92NS

NS=Non significant
+ = Significant interaction at the 80% level of probability.
++ = Significant interaction at the 90% level of probability.
* = Significant interaction at the 95% level of probability or between
the tillage treatment.
** = Significant differences at the 99% level between tillage treatments.
letters = Values between hybrids followed by different letters are
significantly different at the 95% level of probability.

Multiply kg/ha by 0.89 to get pounds/A.
Multiply number/ha by 0.405 to get numbers/A.
Divide grams by 454 to get pounds.
Divide cm by 2.54 to get inches.











Table 2. Corn variables as influenced by subsoiling and corn
hybrids on a flatwood soil in a non-tilled seedbed, Gainesville,
Florida, 1979. (Exp. 2).


Subsoil Subsoil
Variety Yes No Mean Yes No Mean


DeKalb XL78
Asgrow RX114


Dry forage yield kg/ha
22,221 20,822 21,522a
18,613 17,668 18,141b+


Grain yield kg/ha
9,209 9,121 9,165a
7,734 7,539 7,637b++


Mean 20,417 19,245+ 8,472 8,330NS

Percentage grain in forage Ear weight in grams
DeKalb XL78 35.0 37.0 36.0a 153 154 154a+
Asgrow RX114 35.1 36.1 35.6a 145 137 141b

Mean 35.1 36.6NS 149 146NS

Number plants/ha Number ears/ha
DeKalb XL78 6Ub U 1,b676 61,138a 60,600 59,200 59,900a
Asgrow RX114 55,971 51,666 53,819a 54,895 55,218 55,057a

Mean 58,286 56,671NS 57,748 57,209NS

Plant height in cm Ear node height in cm
DeKalb XL78 272 266 2b9a 97 96 97a
Asgrow RX114 268 252 260a 97 102 100a

Mean 270 259NS 97 99NS

NS = Non significant.
+ = Significant interaction at the 80% level of probability.
++ = Significant interaction at the 90% level of probability.
* = Significant interaction at the 95% level of probability or between
the tillage treatment.
** = Significant differences at the 99% level between tillage treatments.
letters = Values between hybrids followed by different letters are
significantly different at the 95% level of probability.

Multiply kg/ha by 0.89 to get pounds/A.
Multiply number/ha by 0.405 to get numbers/A.
Divide grams by 454 to get pounds.
Divide cm by 2.54 to get inches.












Table 3. Corn variables as influenced by subsoiling and corn
hybrids on a flatwood soil in a non-tilled seedbed, Gainesville,
Florida, 1979. (Exp. 3).


Subsoil Subsoil
Variety Yes No Mean Yes No Mean

Dry forage yield kg/ha Grain yield kg/ha
DeKalb XL78 15,542 14,629 15,086a 7,144a 7,232aNS 7,188
Asgrow RX114 16,793 14,751 15,772a 7,389a 6,089a+ 6,739

Mean 16,168 14.690++ 7,267 6.661

Percentage grain in forage Ear weight in grams
DeKalb XL78 38.8 41.8a++ 40.3 154a 150aNS 152
Asgrow RX114 37.2 34.9b++ 36.1 162a 130b++ 146

Mean 38.0 38.4 158 140


DeKalb XL78
Asgrow RX114


Number
42,732
40,364


plants/ha
46,284 44,508a
48,437 44,401a


Mean 41,548 47,361NS 46,445 47,145NS

Plant height in cm Ear node height in cm
DeKalb XL78 256 252 254a 85 76 81a
Asgrow RX114 255 246 251a 99 86 93a

Mean 256 249NS 92 81NS

NS = Non significant.
+ = Significant interaction at the 80% level of probability.
++ = Significant interaction at the 90% level of probability.
* = Significant interaction at the 95% level of probability or between
the tillage treatment.
** = Significant differences at the 99% level between tillage treatments.
letters = Values between hybrids followed by different letters are
significantly different at the 95% level of probability.

Multiply kg/ha by 0.89 to get pounds/A.
Multiply number/ha by 0.405 to get numbers/A.
Divide grams by 454 to get pounds.
Divide cm by 2.54 to get inches.


Number
47,360
45,530


ears/ha
47,683
46,607


47,522a
46,069a'










COMPARISONS OF ENERGY REQUIREMENTS FOR WEED CONTROL
IN CONVENTIONAL AND NO-TILLAGE SOYBEANS

J. M. GOETTE, W. L. CURREY, B. J. BRECKE,
M. B. GREEN, AND R. C. FLUCK1

ABSTRACT

Comparisons of energy efficiency were made between weed control programs
in conventional and no tillage soybean (Glycine max (L.) Merr.) produc-
tion. Two weed control systems of each of conventional and no tillage,
soybean production were compared. Calculated energy inputs and measured
yields were used to determine the specific energy productivity for each
weed control program. Both no tillage operations showed the highest over-
all energy efficiency with paraquat + oryzalin + metribuzin at planting
and metribuzin + 2,4-DB directed post exhibiting the greatest energy
productivity.

INTRODUCTION

The weed control programs in this study were selected to compare the
energy efficiences of preemergence and directed post herbicides in no-till
soybean.production to that of preplant incorporated herbicides in combina-
tion with directed post herbicides or cultivation in conventional production.

Energy is an important factor in determining the efficiency of production.
The importance of energy will increase in the future due to rising fuel
costs and exhaustion of non-renewable resources. Energy conservation is a
major reason for the increasing adoption of no tillage production systems.

There are many different energy units used throughout the world. One of the
more common units is the joule which is of the metric (SI) system. This
report will commonly refer to these energy units as megajoules (MJ) or
10b joules.

Fluck (1979) proposed that a new measure of productivity, the quantity of
product per unit of input energy, be designated and that it be termed energy
productivity. In the SI system of units, a convenient measure of energy
productivity is kilogrammes per megajoule (kg/MJ).

Energy productivity is specific for each agricultural product, location and
time. That is, energy productivity can be used only to compare alternative
production systems and energy conservation practices which result in the
same product, at the same place, at the same time. By calculating the energy
productivity of various production systems, the most energy efficient system
may be determined.

Research Assistant, Associate Professor, Assistant Professor, and Visiting
Professor of Agronomy, and Professor of Agricultural Engineering, respec-
tively. Institute of Food and Agricultural Sciences, University of Florida,
Gainesville, Florida.






I
62
I
RESULTS AND DISCUSSION
Results from these four weed control programs indicated that the no-tillage
operations produced larger yields and required less energy input than the
conventional operations. Therefore, the no-till production systems showed
greater efficiency from an energy point of view due to larger values of
energy productivity.
Many explanations exist for no-tillage efficiency. Robertson and Prine
(1976) and Triplett and Van Doren (1977) listed numerous advantages: I
(1) Less fuel is required due to fewer and less energy-intensive
field operations.
(2) Higher yields often result, particularly in dry land farming
and on well-drained land. Evidence of this report supports
the above statement.
(3) Less time and labor are required.
(4) Land use may be intensified. I
(5) It is possible to farm lower quality land.
(6) Less erosion occurs.
(7) Moisture is conserved. i
(8) Soil structure may be improved.
(9) There is lower investment for machinery. I
The no-till weed control program that exhibited the greatest energy pro-
ductivity was the combination of paraquat + oryzalin + metribuzin at
planting with metribuzin + 2,4-DB directed post. This herbicide program
produced an efficiency rating 21.7% greater than that of the highest yield-
ing conventional program and 27.3% greater than that of the lowest yielding
conventional program.
The no-till preemergence application of paraquat, alachlor, and metribuzin g
contributed the second highest energy productivity. This weed control I
program was found to be 17.8% greater than that of the highest yielding
conventional program and 23.7% greater than that of the lowest yielding
conventional program which contained two cultivations.
Green and McCulloch (1976) stated that, in general, at least two mechanical
weeding operations are required to achieve the effect of one chemical treat-
ment. This statement is supported by the poor performance of the conventional I
program which contained two cultivations. It produced the lowest yield
while requiring the greatest total energy input. When compared to the g
directed post-treatments in conventional production, the mechanical weeding I
again proved to be the least efficient. This comparison supports the state-
ment that chemicals are an efficient use of fossil fuel.


I








The purpose of this research was to determine the energy requirements of
various weed control programs in no-tillage and conventional production of
soybeans and to compare their energy efficiencies.

MATERIALS AND METHODS

Field experiments to evaluate the energy productivity of weed control
programs in no-till and conventional soybean production were initiated in
June of 1979 at the Agricultural Research Center located in Jay, Florida.
The soil type was a Tifton fine sandy loam. Preplant incorporated and
preemergence herbicides were applied during the first week in June with
the directed-post treatments applied August 1. Soybeans yields for these
four weed control programs were obtained in the fall.

The energy inputs for manufacturing soybean herbicides are given in Table 1.
This energy input is the product of the energy requirement for manufacturing
times the application rate. The weed control programs in no-tillage and
conventional soybean production are listed in Table 2. The no-till programs
consist of preemergence applications with one program having additional
directed-post treatments. The conventional programs include preplant incor-
porated treatments with the first program containing two cultivations and
the second having directed-post treatments. The itemized energy inputs
include the energy required for herbicide production, incorporation, culti-
vation, and application of directed-post treatments. The energy inputs for
preplant and preemergence application are included with the incorporation
and planting operations.

When examining energy productivity, all inputs of production must be con-
sidered. For conventional soybean production, the total energy input less
the energy required for herbicide production, application, incorporation
and cultivation equals a base energy input of 15,164 MJ/ha. The base
energy input includes energy for fertilizer, fungicides, insecticides, labor,
and machinery. This value must be added with the individual weed control
inputs ;to give an accurate estimate of the total energy input.

No-till production systems require less energy inputs of production. Fluck
and Baird (1980) state that fuel reductions result in an average saving
of 1170 MJ/ha. Lower labor requirements also result in a decrease in energy
consumption. Elimination of two field operations might reduce labor inputs
by one hour per hectare or labor energy requirements by about 75 MJ/ha.
Lower energy requirements for less machinery will be in the order of 100-
200 MJ/ha. Total energy reductions for limited tillage as compared to con-
ventional cultivation may be in the order of 1395 MJ/ha for the base energy
input. This reduction of energy consumption in no-till production results
in a base energy input of 13,769 MJ/ha as compared to 15,164 MJ/ha for con-
ventional production systems.

The energy productivity (Table 3) is calculated by dividing the yield (kg/ha)
by the total energy input (MJ/ha). Fluck and Baird (1980) state that energy
productivity is intended to and can serve as an evaluator of how efficiently
energy is utilized in production systems yielding a particular product. This
value illustrates the quantity of soybeans produced per megajoule of input
energy.





I
64

The findings of this study strongly support the advancement of herbicide
weed control programs in no-tillage soybeans over that of conventional
tillage practices. The higher energy productivity of weed control in
no-till soybeans illustrates the effectiveness of no-tillage in combination
with proper weed control programs.
LITERATURE CITED I
1. Brecke, B. J. 1979. Weed Science annual research report. Institute
of Food and Agricultural Sciences, University of Florida.
pp. 79-83.
2. Fluck, R. C. 1979. Energy productivity: A measure of energy utiliza-
tion in agricultural systems. Applied Science Publishers Ltd.,
England. p. 32.
3. Fluck, R. C. and C. D. Baird. 1980. Agricultural energetic. AVI
Publishing Company, Inc. Westport, Connecticut. pp. 51-54,
145-147.
4. Green, M. B. 1978. Eating oil. Westview Press, Boulder, Colorado. I
5. Green, M. B. and A. McCulloch. 1976. Energy considerations in the I
use of herbicides. J. Sci. Fd. Agric. 27:95-100.

I

I

I

I

I

I

I

I

I

I



















Table 1. ENERGY INPUT FOR


Herbicide

Paraquat

Trifluralin

Alachlkor

Oryzalin

Metribuzin

2,4-DB


Rate
Ib/A

.25

.50

2.0

1.0

.50

.25


SOYBEAN HERBICIDE PRODUCTION

Energy
Rate Requirements
kg/ha MJ/kg

.28 460

.56 150

2.24 280

1.12 150

.56 410

.28 87


Herbicide1
Energy Input
MJ/ha

129

84

627

168

230

24


Product of energy requirement times rate of application.






66

Table 2. ENERGY INPUTS FOR WEED CONTROL PROGRAMS IN NO TILLAGE AND CONVENTIONAL
SOYBEANS

Cultivation (one) 390 MJ/ha
Application (one) 73 MJ/ha
Incorporation (2-disc) 750 MJ/ha
Weed Control Itemized Energy Subtotal Energy
Programs Inputs MJ/ha Inputs MJ/ha
A. No Tillage
(1) Paraquat pre + 129
Alachlor pre + 627
Metribuzin pre 230 986
(2) Paraquat pre + 129
Oryzalin pre + 168
Metribuzin pre + 230
Metribuzin DP + 230
2,4-DB DP 24
Application (DP) 73 854
B. Conventional Tillage
(3) Trifluralin ppi + 84
Metribuzin ppi + 230
Incorporation + 750
Cultivations (2) 780 1844
(4) Trifluralin ppi + 84
Metribuzin ppi + 230
Incorporation + 750
Metribuzin DP + 230
2,4-DB DP + 24
Application (DP) 73 1391


I

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I

I

I

I













Table 3. ENERGY PRODUCTIVITY OF WEED CONTROL PROGRAMS IN NO-TILLAGE AND
CONVENTIONAL SOYBEAN PRODUCTION.


Yield
kg/ha


Weed Control
Program

(1); Paraquat +
Alachlor +
Metribuzin

(2) Paraquat +
Oryzalin +
Metribuzin +
Metribuzin +
2,4-DB

(3) Trifluralin +
Metribuzin +
Cultivations (2)

(4) Trifluralin +
Metribuzin +
Metribuzin +
2,4-DB;


2345


2439



2063




2164


Total EnergyI
Input MJ/ha


14755





14623



17008




16555


Energy2
Productivity kg/MJ


.1589





.1668



.1213




.1307


Conventional Tillage 15,164 MJ/ha + Weed Control Input.
No Tillage 13,769 MJ/ha + Weed Control Input.

2Energy Productivity = Yield kg/ha
Total Energy Inputs MJ/ha


= Quantity of soybeans produced per megajoule of input energy.


__






I


I
ARE NO-TILL MULTICROPPING PRODUCTION METHODS
PROFITABLE FOR FLORIDA FARMERS? 1

DAN L. GUNTER, NANCY MCCABE AND RAY GALLAHER

Increasing costs of agricultural inputs, especially energy and credit, are
forcing farmers to evaluate their conventional production methods to determine
if lower cost practices can be identified. No-till and multicropping are two
practices being given increasing consideration.
Benefits of these practices have been extolled in many of the agriculture
publications. The benefits often mentioned include:
1. better utilization of land,
2. reduced fuel and labor costs,
3. spreading of fixed costs of machinery over more annual hours of use, and
4. possible increased yields.

New planting equipment designed to operate in unplowed stubble or mulch and I
improved herbicides to control weeds and grasses reduce the problems farmers
have found to be associated with no-till production practices.
Scientists working for the Institute of Food and Agricultural Sciences (IFAS)
at the University of Florida have been conducting research on no-till and multi-
cropping methods for some of the more important Florida field crops. 3

The purpose of this paper is to report an evaluation of the profitability of
producing corn and soybeans using no-till, multicropping practices. A profit-
ability comparison is also made to conventional corn and soybean production.

PROCEDURE

We used data collected from IFAS experiments which were first conducted during
1978 at the University farm near Williston. Multicropping was used in both the
no-till and conventionally produced crops. Rye was harvested as hay and/or
grain and followed by either corn or soybeans planted with conventional or no-
till methods.
Corn and soybeans were no-till planted in a single operation using a two row
Brown-Harden Super Seeder with a subsoiler. Conventionally planted corn and
soybeans required harrowing, plowing, harrowing and then planting.
To compare the profitability of these enterprises we developed budgets which
are a systematic listing of income and expenses for a production period. The n

Dan L. Gunter is an Extension Production Economist and Nancy McCabe is an
undergraduate student, Food and Resource Economics Department, McCarty Hall,
University of Florida, Gainesville, Florida 32611. Ray N. Gallaher is an
Associate Professor of Agronomy, Department of Agronomy, Agronomy Research
Support Lab, Wallace Building, University of Florida, Gainesville, Florida
32611.
68









budgets show income, variable costs, harvest costs, fixed costs and net returns.
The budgeted costs are based on 1980 input price levels and the annual ownership
and operation costs of the following set of machinery and equipment:

Machinery and Equipment

USED IN NO-TILL USED IN CONV.
PRODUCTION PRODUCTION
Tractor, 55 hp X X
Truck, 2 ton X X
Grain Combine X X
Sprayer X X
Planter X
Super Seeder 2 row X X
MB Plow (4) X
Harrow X
Fertilizer Spreader X X

ESTIMATED COSTS FOR SOYBEANS

The budget for conventionally tilled soybeans is shown in Figure 1. Yield
from the experiment was 29 bushels per acre, variable costs are $78.87 and
harvest costs, which include labor and operating expenses associated with the
machinery, are $7.81 per acre. The total variable costs which can be thought
of as "out-of-pocket" expenses totaled $86.68. The fixed costs are $21.52
and include the normal "DIRTI" five expenses associated with ownership of
machinery and equipment. The DIRTI five are: Depreciation, Interest, Repairs,
Taxes, and Insurance. Total per acre costs are $108.20, which subtracted from
gross receipts leaves a net return to land and management of $65.80 per acre.

Budgeted costs and returns for no-till soybeans are shown in Figure 2. The
net returns for no-till production are $127.45 as compared to $65.80 using
conventional practices. As expected, machinery and tractor costs are lower
using the no-till practices. The addition of Furadan almost offsets the cost
savings from reduced machinery usage; however, increased yield is attributed
to its use. The difference in net revenue seen by comparing the budgets is
due to difference in yields. The no-till production method resulted in a 10
bushel higher yield than conventionally produced soybeans.

ESTIMATED COSTS FOR CORN

Budgets for no-till and conventionally produced corn are shown in Figures 3
and 4. The revenue and costs for alternative corn production methods are:

NO-TILL CONVENTIONAL
- -Dollars- -
Revenue 263.25 256.50
Total Costs 156.77 166.04
Returns to Land and
Management 106.48 90.46







CONVENTIONAL TILL SOYBEANS IN RYE STUBBLE 70
WELL DRAINED ACIDIC SANDY LOAM
LEVY COUNTY# 1980 PRICES -


PRICE OR
UNIT COST/UNIT


QUANTITY


VALUE OR
COST


t* GROSS RECEIPTS FROM PRODUCTION
TOTAL

2. VARIABLE COSTS
PREHARVEST
SOYBEAN SEED
TOXAPHENE
PARAQUAT
LASSO
LEXONE
BASAGRAN
ORTHO X 77
INNOCULANT
MACHINERY
TRACTORS
LA3OR(TRACTOR & MACHINERY)
INTEREST ON OP. CAP.
SUBTOTAL* PRE-HARVEST

-ARVEST COSTS
MACHINERY
LABOR(TRACTOR & MACHINERY)
SUBTOTAL. HARVEST


BUe



8U.
LBS.
PT.
LBS.
LBS.
QTo
PT.
BU.
ACRE
ACRE
HOUR
DOL


ACRE
HOUR


6.00



13.00
0.77
5.30
4.50
8.75
7 75
1.75
1.70
2.46
5.11
3.50
0.14


5.47
3.50


I
29.00 44t
S 1; I


1,00
4.00
2.50
2.00
0.38
2.25
0.67
1.00
1.00
1.00
1.65
25.32


13.00
3.08
13.25
9.00
3.32
17.44
1*17
1 70
2.46
5.11
5.79
-7t3
S too


$
1.00 5.47
0.67 $-f34
$ '93 1


TOTAL VARIABLE COST


$ 86.68

$ 87.32


3. INCOME ABOVE VARIABLE COSTS


4. FIXED COSTS
MACHINERY
TRACTOR S
TOTAL FIXED COSTS


ACRE
ACRE


17. 21
4.31


5. T3TAL COSTS


6. NET RETURNS
BROWN-HARDEN SUPERSEEDER
COBB SOYBEANSo SUBSOILED
NANCY MCCABE RAY GALLAHER
BUDGET IDENTIFICATION NUMBER------


A


1.00 17.21
1.00 04klI 1
$ 10. 52
$ 108.20 U


$ 65.80


3/10/80 I


124438040 10118


ANNUAL CAPITAL MONTH 11

PROCESSED BY FARM SYSTEMS LAB FOOD & RESOURCE ECON. DEPT.,U. OF FLORIDA
PROGRAM DEVELOPED BY DEPT. OF AG. ECON. OKLAHOMA STATE UNIVERSITY
DATE PRINTED: 30 APRIL 1980


Figure 1.







NO-TILL SOYBEANS IN RYE STUBBLE
WELL DRAINED ACIDIC SANDY LOAM
LEVY COUNTY, 1980 PRICES


PRICE OR
UNIT COST/UNIT


QUANTITY


VALUE OR,
COST


1, GROSS RECEIPTS FROM PRODUCTION

TOTAL

2. VARIA8BLE COSTS
PREHARVEST
SOYBEAN SEED
TOXAPHENE
PARAQUAT
LASSO
LEXONE
BASAGRAN
ORTHO X 77
INNOCULANT
FURADAN
MACH NERY
TRACTORS
LABOR(TRACTOR & MACHINERY)
INTEREST ON OP. CAP.
SUBTOTAL. PRE-HARVEST

HARVEST COSTS
MACHINERY:
LABOR(TRACTOR & MACHINERY)
SUBTOTAL, HARVEST

TOTAL, VARIABLE COST

3. INCOME ABOVE VARIABLE COSTS.

4. = IXED COSTS,
MACHINERY
TRACTORS
TOTAL FIXED COSTS


BU.



BU.
LBS.
PT.
LBS.
LBS.
QT.
PT.
BUS
LBS.
ACRE
ACRE
HOUR
DOL.


ACRE
HOUR


6.00



13.00
0.77
5.30
4.50
8.75
7.75
1.75
1.70
0.72
2.01
2.66
3.50
0.14


5.47
3.50


$
39.00 234*00
S 234.00


1.00
4.00
2.50
2.00
0.38
2.25
0.67
1.00
10.00
1.00
1.00
0 86
27 11


13.00
3.08
13 25
9.00
3.32
17*44
1.17
1.70
7.20
2.01
2.66
3.02

$ 8064


s
1.00 5.47
0.67 --SAM
$ 7*8


S 88.45


ACRE
ACRE


15.86
2.25


S 145.55
$
1.00 15.86
1. .00 T


5. TOTAL COSTS

6. NET RETURNS


S 106.55

S 127.45


3/10/80


BROWJ- HARDEN SUPERSEEDER
COBB SOYBEANS, SUBSOILED, WITH FURADAN
NANCY MCCABE RAY GALLAHER


BUDGET IDENTIFICATION NUMBER--- 124438040 10118
ANNUAL CAPITAL MONTH It

PROCESSED BY FARM SYSTEMS LAB FOOD & RESOURCE ECON. DEPT*.U. OF FLORIDA
PROGRAM DEVELOPED BY DEPT. OF AG. ECON. OKLAHOMA STATE UNIVERSITY
DATE PRINTED: 30 APRIL 1980


Figure 2.







NO-TILL CORN GRAIN IN RYE HAY STUBBLE 72
WELL DRAINED ACIDIC SANDY LOAM
LEVY COUNTY, 1980 PRICES


PRICE OR
UNIT COST/UNIT


QUANTITY


VALUE OR
COST


1. GROSS RECEIPTS FROM PRODUCTION
CORN
TOTAL

2. VARIABLE COSTS
PREHARVEST
CORN SEED
N&P&K
NITROGEN
FURADAN
ATRAZINE
PARAQUAT
ORTHO X 77
LOROX
MACHINERY
TRACTORS
LABOR(TRACTOR & MACHINERY)
INTEREST ON OP* CAP.
SUBTOTAL, PRE-HARVEST

HARVEST COSTS
MACHINERY
LABOR(TRACTOR & MACHINERY)
SUBTOTAL, HARVEST

TOTAL VARIABLE COST

3. INCOME ABOVE VARIABLE COSTS


4. FI XED COSTS
MACHINERY
TRACTORS
TOTAL FIXED COSTS


BU.



LBS.
CWT.
LBS.
LBS.
LBS.
PT*
PT.
LBS.
ACRE
ACRE
HOUR
DOL.


ACRE
HOUR


ACRE
ACRE


s
2.25 117.00 263.5
S 263.25


0.85
6.00
0.24
0.72
1.83
5.30
1.75
4.50
2.06
3.36
3.50
0.14


6.45
3.50


16.84
2.83


5. TOTAL COSTS


19.00
6.00
120.00
20*00
2.00
1.50
0.66
1.00
1.00
1.00
1.09
41.78


16.15
36.00
28.80
14.40
3.66
7.95
1.15
4.50
2.06
3.36
3.80

S 127.68


1.00 6.45
0.85 2t97
S 9.42

$ 137.10


S 126.15


1.00 16.84
1 1500677
$ 19567
S 156.77 g


$ 106.48


6. NET RETURNS
BROWM-HARDEN SUPERSEEDER
FUNKS G-4507 CORN. SUBSOILED, 5-10-5
NANCY MCCABE RAY GALLAHER


3/10/80 1


BUDGET IDENTIFICATION NUMBER--- 104438040 10118
ANNUAL CAPITAL MONTH 7

PROCESSED BY FARM SYSTEMS LAB FOOD & RESOURCE ECON. DEPT.,U. OF FLORIDA
PROGRAM DEVELOPED BY DEPT. OF AG. ECON. OKLAHOMA STATE UNIVERSITY
DATE PRINTED: 30 APRIL 1980

Figure 3.







CONVENTIONAL TILL CORN IN RYE HAY STUBBLE
WELL DRAINED ACIDIC SANDY LOAM
LEVY COUNTY. 1980 PRICES


PRICE OR
UNIT COST/UNIT


QUANTITY


VALUE OR
COST


1. GROSS RECEIPTS FROM PRODUCTION
CORN
TOTAL

2. VARIABLE COSTS
PREHARVEST
CORN SEED
N&P&K
NITROGEN
FURAOAN
ATRAZINE
PARAQUA T
ORTHO X 77
LOROX
MACHINERY
TRACTORS
LABORITRACTOR & MACHINERY)
INTEREST ON OP. CAP.
SUBTOTAL, PRE-HARVEST

HARVEST COSTS
MACHINERY
LABOR(TRACTOR & MACHINERY)
SUBTOTAL, HARVEST

TOTAL VARIABLE COST

3. INCOME ABOVE VARIABLE COSTS


4. FIXED COSTS
MACHINERY
TRACTORS
TOTAL FIXED COSTS


BU.



LBS.
CWT.
LBS.
LBS.
LBS*
PT*
PT.
LBS.
ACRE
ACRE
HOUR
DOL.


ACRE
HOUR


ACRE
ACRE


S
2.25 114.00 6.,50.
$ 256.50 -


0.85
6.00
0.24
0.72
1.83
5.30
1.75
4.50
2.52
5.81
3.50
0. 14


6.45
3.50


18.19
4.90


19.00
6.00
120.00
20.00
2.00
1.50
0.66
100
1.00
1.00
1.88
42.99


16. 15
36.00
28.80
14.40
3.66
7.95
1.15
4.50
2.52
5.81
6.58

S133.53


1.00 6.45
0.85 297


$ 142.95


1.00
1.00


5. TOTAL COSTS

6. NET RETURNS


BROWN-HARDEN SUPERSEEDER
FUNKS G-4:507 CORN, SUBSOILED, 5-10-5
NANCY MCCABE RAY GALLAHER


S 113.55

18.19


$ 166.04

$ 90.46


3/10/80


BUDGET IDENTIFICATION NUMBER--- 104438040 10118
ANNUAL CAPITAL MONTH 7

PROCESSED BY FARM SYSTEMS LAB FOOD & RESOURCE ECON. DEPT.eU. OF FLORIDA
PROGRAM ;DEVELOPED BY DEPT. OF AG. ECON. OKLAHOMA STATE UNIVERSITY
DATE PRINTED: 30 APRIL 1980


Figure 4.






74I


Yields observed were three bushels per acre higher in the no-till field while
the machinery operating costs were lower accounting for the $16.02 difference
in net revenue.

FUEL AND LABOR COSTS COMPARISONS

With increased interest in energy conservation, producers can compare fuel use
for the alternative production methods. Figure 5 shows the gallons per acre of
gasoline and diesel fuel. The no-till practices require almost three gallons I
less fuel than the conventional practices. This translates into more than a $3
per acre cost savings at 1980 fuel price levels. However, fuel savings alone
may not provide enough incentive for farmers to adopt a new set of cultural
practices.
In addition to the fuel savings, labor and machinery requirements are reduced g
with no-till practices. Figure 6 shows a labor savings of almost 0.8 of an
hour/acre for both corn and soybeans produced using no-till production methods.
Likewise, machinery hours required are lower using no-till. For example, the
variable costs per acre for the tractor is $5.11 for conventionally planted
soybeans and $2.66 for no-till (Figure 7). The variable costs for the tractor
for no-till corn production is $3.36 per acre as compared with $5.81 fif produced
conventionally. 3

PROFITABILITY OF MULTICROPPING

Other fixed or variable cost comparisons can be made, but the real test is
whether or not net returns are higher? If we compare net returns per acre where
corn and soybeans are multicropped with hay, yielding both rye grain and hay,
the total net returns are as follows:
NO-TILL CONV. TILL NO-TILL CONV. TILL
CORN CORN SOYBEANS SOYBEANS
Single crop $106.48 $ 90.46 $127.45 $65.80
Rye grain and hay 14.29 14.29 14.29 14.29
Total returns/acre $120.77 $104.75 $141.74 $80.09

CONCLUSIONS I

The results of the experiments and budget analysis show that no-till and multi-
cropping are more profitable than conventional cultural practices to produce
the same crops. Differences in profits are due to reduced costs and higher
yields using no-till production. i
These results stem from one year's experiment. Further experimental work needs
to be undertaken to evaluate the effectiveness of no-till practices under farm
conditions. Farmers considering no-till practices should do some careful
feasibility analyses before they trade their mold board plow and disk for one-
pass planting equipment.

I


I

















51.810
5.81


5.27


Gallons

10


5



0


CORN


Gas


Diesel


SOYBEANS


Figure 5. Fuel Used Per Acre.


Dollars


1.94


2.75


1.53


2.32


no- cony. no- conv.
till till till till


CORN


SOYBEANS


Figure 6. Labor Requirements For
Conventional and No-
Till Corn and Soybeans.


3.361


5.81


2.66


5.11


no- conv. no- conv.
till till till till


CORN


SOYBEANS


Figure 7. Variable Costs of
Tractor Per Acre.


no- conv. no- conv.
till till till till


Hours
Labor 3.0





2.0





1.0


:1.80:

3.91


3.37






I


ALTERNATIVE TILLAGE IN JEFFERSON COUNTY, FLORIDA

Larry A. Halsey and Phil Worley


Pine Seedling No Til Site Preparation Demonstration

A significant portion of the pine timber and pulpwood industry in North
Florida is on farm land. Private landowners receive technical assist-
ance from the Florida Department of Agriculture, Division of Forestry,
as well as the County Cooperative Extension Service.

It is estimated that in Jefferson County 20% of the acreage planted in
relatively small blocks by private landowners is on abandoned sod or
pasture. Various methods of conventional site preparations are employed,
including plowing and discing, roto-tilling, or bedding. All constitute
a significant portion of the total cost of planting pines. Seedlings I
occasionally are planted in sods with no mechanical preparation. Pines
planted directly in sod or in poorly prepared sites must compete with
extensive grass root systems for moisture and nutrients during estab-
lishment and early growth years.

The Forester and the County Extension Director initiated a demonstration
"no-til" pine seedling block to determine if chemical site preparation
would eliminate a number of the production problems associated with
conventional methods.

Together with Kent Frost, Product Development Specialist of Monsanto,
and landowner Ferd Naughton, a 1.25 acre site was selected for the g
demonstration. The site was an abandoned Pensacola Bahiagrass pasture.
Roundup (glysophate) herbicide was applied at 3 pounds active ingre-
dient per acre (broadcast basis) over 4 foot strips on 12 foot middles
on October 22, 1979. Seedlings were transplanted in the herbicide
treated strips on 12' x 5' spacings on January 29, 1980. Spring re-
growth of the sod was uniform in the untreated middles between treated
strips. Perennial grass control under the treatment approached 100%,
with virtually no regrowth. Germination of spring annual weeds in the
strip was observed. As of the middle of April, following the January
planting, a preliminary estimate of seedling survival was 97%.

The site was established on small acreage for observation only. On the
basis of the apparent effectiveness of this chemical site preparation
methods, a follow-up trial on 8-10 acres is anticipated in fall and
winter of 1980-81. Side-by-side plantings under conventional site
preparation and Roundup treatment will be conducted. The following
data will be compiled in the experiment: 1) Comparative fuel consump-
tions of the various techniques; and equipment, material, labor, and
other costs for accurate budget comparisons. 2) Penitrometer comparisons


Larry Halsey is County Extension Director, Jefferson County, Cooperative
Extension Service, IFAS, University of Florida. Phil Worley is County
Forester, Jefferson County, Division of Forestry, Florida Department of
Agriculture and Consumer Services.
76 I









of the various site preparations methods, as an index of the ease of
entry of the coulter of the seedling planter unit. 3) Growth character-
istics at various intervals following planting, as well as survival and
mortality counts. 4) Observations of root systems of sample seedlings
under each of the various preparation methods.

Assumed advantages of the "no-til" or chemically prepared site include
reduction of cost of site preparation, better survival and early growth
due to reduced competition for nutrients and moisture, and reduced ero-
sion and pollution from runoff due to the mulch cover. It should be
noted that the Roundup label for use does not include this specific
application. The trial is being conducted in cooperation with Monsanto
Company representatives for experimental use only.


Minimum Tillage in Row Crops

During 1978, 135,163 acres of cropland on 2,135 farms in the United
States were assisted through cost share practices involving conservation
tillage systems (SL9) under the Agricultural Stabilization and Conser-
vation Service (USDA-ASCS). In Florida, 1978 acreage totaled 535 acres
on three farms. In 1979, 37 farms received cost-share assistance under
Agricultural Conservation Program (ACP) totalling 2,182 acres to demon-
strate minimum or reduced tillage systems in farming. Jefferson County
growers are receiving cost-share on 5 farms with over 320 acres in 1980,
for minimum tillage demonstrations, with total acreage in non-conventional
planting or tillage at 3-4,000 acres.

Jefferson County is located along the Florida-Georgia border. Farm land
is gently sloping to hilly, with predominate soil type of Ultisols, with
sandy to loamy sand textures of 6.5-8% clay fraction and 2-4% organic
matter. Corn, soybeans, peanuts, tobacco and small grains for seed and
forage are the main agronomic crops. Up to 25,000 acres of small grains
or small grains with clover are planted annually for winter and spring
grazing. Corn and soybean crops often are planted behind winter annual
pastures. Corn under better than average high yield management yields
80-85 bu/A; soybean yields of 30-33 bu/A are normal. Both crops are
planted under minimum tillage; however, a yield history using reduced
tillage is unavailable.

Various alternative planting and tillage systems are currently being
employed, from strict "no-til" planting in rye or oats in an absolute
"once over" operation to discing once or twice prior to planting with
no-til equipment. Reduction of erosion, reduction of time spent in
planting, reduction in fuel consumption and increased moisture avail-
ability during drought periods around corn tassle and silking stage
are most often referenced by farmers using reduced tillage methods as
justification for employing the systems. Farmers are assisted in al-
ternative tillage techniques by the ASCS, the Soil Conservation Service,
and equipment and chemical suppliers.






I


I

MINIMUM TILLAGE DEMONSTRATION PROJECT
AGRICULTURAL CONSERVATION PROGRAM (ACP)

By

Betty P. Jones, County Executive Director, Alachua County ASCS Office

ACP Program Objectives I

The Agricultural Conservation Program (ACP) provides cost-sharing
as an incentive to encourage farmers and ranchers to carry out conser-
vation measures that:

1. control erosion and sedimentation from agricultural
land and conserve the water resources on such land;

2. control pollution from animal wastes;

3. conserve wildlife habitat;

4. facilitate sound resource management systems through
soil and water conservation; I

5. contribute to the national objectives of assuring a
continuous supply of food and fiber necessary for the
maintenance of a strong and healthy people and
economy; and

6. assures performance of the type conservation measures
needed to improve water quality in rural America.

ACP is a joint effort by agricultural producers and Government I
to restore and preserve the environment and basic land resources.
Cost-share assistance is available under annual or long-term
agreements.

Program Administration

The ACP is administered by Agricultural Stabilization and Conser- I
vation (ASC) State, county and community committees, working under the
general direction of the Agricultural Stabilization and Conservation
Service (ASCS) of the U.S. Department of Agriculture. County and
community committee members are elected by farmers within the local
county. Funds for cost-sharing are appropriated annually by the Congress.
In recent years, the appropriation has been about $190,000,000.

The ASCS county committee in the local county approves cost-sharing
on the basis of requests filed by individual producers. After receiving
the official practice approval, performance is done according to speci-
fications developed for the specific practice. All expenses incurred
during performance are paid by the farmer. Later, after the practice *
has been certified as being performed according to practice specifi-
cations, the farmer is reimbursed on an average of from 50 to 75
percent of the out-of-pocket cost of performing the practice.
78











Technical Assistance for Farmers

Farmers are provided necessary technical assistance to perform
engineering type practices by the Soil Conservation Service (SCS).
Forestry practices are performed under the supervision of the
Florida Division of Forestry personnel located in the county where
the participating farm is located.

Demonstration Project Concept

Demonstration type special projects are authorized under the
ACP. The purpose of such projects is to help achieve enduring soil
and water conservation and environmental benefits through the use of
innovative, up-to-date methods for treating conservation problems.
Cost-share assistance is provided under approved projects as an
incentive to encourage farmer participation.

Alachua County Demonstration Project

Based on past experience, farmers generally consider minimum
tillage farming ineffective and conducive to crop failure. With
the availability of existing herbicides, insecticides, and pesticides,
and improved planting equipment, the Alachua County ASC Committee
recognized the potential and the advantages of conservation tillage
farming. The Committee, working closely with the Alachua County
ACP Development Group, recommended the special project to the Florida
State ASC Committee for approval and funding. The project was de-
signed to demonstrate on a community-wide basis the techniques to be
followed when using a minimum tillage operation to grow corn and
soybeans.

Cost-share assistance was provided under the project for farmers
to utilize ACP practice SL9 Conservation Tillage Systems. (See
Exhibit 1 for practice specifications.) A 70 percent cost-share
rate was approved which reimbursed the participating farmer for most
of the out-of-pocket expense incurred above those expenses normally
associated with "standard" row-cropping methods.

In order for farmers to become familiar with and to utilize the
most recent developments in multi-cropping minimum tillage and no-
tillage, a farm visit was made to each participating farm to inspect
the fields and to develop a plan of operation. The plans were de-
veloped in consultation with Dr. Raymond Gallaher, Associate Professor
of Agronomy, Institute of Food and Agricultural Services, University
of Florida; the Cooperative Extension Agent; and the SCS District
Conservationist, and included specific recommendations for farmers
to follow in planting and providing necessary weed control (see Exhibit 2). A
follow-up inspection was made by ASCS to check compliance.

Farm tours were held in connection with the project to demonstrate
planting techniques, and to evaluate plant growth and weed control
during the growing season.






80

1

Farmer Participation

A total of 20 farmers participated in the demonstration project.
These producers grew 940 acres of corn and grain sorghum and 412 acres
of soybeans. Yields were comparable to those for crops grown using
the "standard" row-cropping system.

Summary I

Participating farmers were generally successful in carrying out
their first-year minimum tillage operation. Yields were satisfactory.
Most farmers reported a reduction in fuel cost. However, several
farmers indicated that fuel savings were offset by the increased
expense incurred for weed control. Overall, most participating
farmers believe crops can be grown with less expense using multi-
cropping minimum or no-tillage systems than with the "standard"
row-cropping system.
Additional experience is needed, however, for producers to realize
the maximum benefits. They believe that the system should be tested
over a period of years -- i.e. three to five years -- in order for g
them to assess benefits. Some farmers are concerned about the impact
that a wet growing season or an unusual dry growing season would have
on yields. Most participants believe that weed control would be a
serious problem during wet years.
The SL9 Conservation Tillage System ACP practice specifications
have been changed to permit farmers to receive cost-sharing for three
consecutive years. This change will permit farmers to do demonstration I
planting to help them further evaluate minimum tillage operations, to
gain the necessary experience, and to develop techniques that will be
most effective under the system.

Acknowledgments: The author and the Alachua County ASC Committee
wish to express their appreciation to Dr. Raymond
N. Gallaher, Coordinator, Agronomy Research Support
Laboratory, University of Florida; Mr. A. T. Andrews,
Alachua County Agent; and Norman Porter, SCS
District Conservationist for their technical assis-
tance; and to those participating farmers who were
willing to expend their resources at considerable
risk to demonstrate conservation tillage systems
during the 1979 crop year. We learn by doing.
Thank you for sharing your experience with
Alachua County farmers. i


I


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EXHIBIT 1


SL9 CONSERVATION TILLAGE SYSTEMS


A Purpose. To demonstrate a method of installing tillage
systems and residue management systems of farming that
will:

1 Protect soil from wind and water erosion and improve
soil permeability.

2 Prevent or reduce pollution from sediment and chemically
contaminated runoff from agricultural non-point sources.

B Applicability. To cropland needing erosion or sediment
control while being devoted to the production of intertilled
or small grain crops.

C Policies.

1 Cost-sharing is not authorized where the farmer has
already adopted a satisfactory conservation tillage
system of farming.

2 Cost-sharing for this practice may be approved for no
more than 3 years with the same person.

3 The land involved must be protected by crop residue,
temporary cover, or other permitted management methods
from harvest until the next planting.

4 Eligible tillage operations may consist of:

a Chisel plowing with other limited operations, or

b Plow-plant, or

c Light tillage without plowing, or

d Approved slot or strip tillage operations ahead
of planting, or

e Planting on chemically killed sods, or

f Other similar methods.

5 All tillage operations must be performed as nearly as
practicable on the contour or parallel to terraces,
except where the committee determines that this is not
necessary.






82
EXHIBIT 1



6 Chemicals used in performing this practice must be
Federally, State and locally registered and must be
applied strictly in accordance with authorized uses,
directions on the label, and other Federal or State
policies and requirements.

7 Cost-sharing is not authorized for designated set-
aside acreage. I

8 Cost-sharing is not authorized for acreages where
the crop is cultivated unless prior approval of the
method of cultivation is approved in advance by the
county committee.

D Specifications. I

1 Performance of this practice shall be carried out
according to the plan developed in consultation
with the Cooperative Extension Agent, a represen-
tative of the Institute of Food and Agricultural
Sciences, Department of Agronomy, University of
Florida, and the SCS District Conservationist.

2 Cost-sharing is authorized on a per-acre basis for
the following:

a Planter and related equipment. (Excludes
tractor). i

b Planting operation. (Includes tractor and
labor). I

c Applying herbicide. (Includes material).

d Insecticide -- material only. I

e Applying post directed application of
herbicide. (Includes material), .

3 Performance shall be verified by a representative
of the county committee before approval of cost-
share payment.

E Maximum Cost-share Rates.

1 Regular Rates.

a $ 3.50 per acre for planter and related equipment. I



I


I







EXHIBIT 1 83


b $ 4.20 per acre for planting.

c $12.25 per acre to apply herbicide.

d $ 8.40 per acre for the insecticide.

e $ 7.70 per acre to apply post directed
application of herbicide.

2 Rates for Low-income Farmers.

a $ 4.00 per acre for planter and related
equipment.

b $ 4.80 per acre for planting.

c $14.00 per acre to apply herbicide.

d $ 9.60 per acre for the insecticide.

e $ 8.80 per acre to apply post directed
application of herbicide.






84 I


EXHIBIT 2


CONSERVATION TILLAGE SYSTEMS

NAME FSN

Performance of practice SL9 must be carried out according to a plan
developed by ASCS in consultation with the Extension Agent; Department
of Agronomy, University of Florida; and the SCS District Conservationist.
The following recommendations are to be used as a guide. If for any
reason they cannot be followed, contact the County Executive Director
for other recommendations.

Crop:


Acreage:


Photograph Number:


Irrigated:

Non-irrigated:


LiI

LII


Succeeding Crop or Land Use:


Contour Planting:

Conventional Planting:

Apply Herbicide:


zzI

II


Suggested Material: 1/


Apply Insecticide:


Suggested Material: 1/


Apply Postemergency Herbicides:
Suggested Material: 1/


I i


1/ Identify material that should be used for the crop to be planted.
Attach any pamphlet, written guidelines, etc., applicable to the
use of the material to the farmer's copy of the plan before delivery
to the farmer.


,1-I










EXHIBIT 2


Equipment to be Used:


Land Preparation Authorized:


General Comments and Additional Guidelines:






I


I

ESTABLISHMENT OF LEGUMES IN BAHIAGRASS SOD

R. S. KALMBACHER

I
Bahiagrass (Paspalum notatum) is widely grown from Texas through the
Carolinas, and in Florida is a major pasture grass. It is a tough
competitor which forms an extremely dense sod crowded with stubby
stolons. Bahiagrass is popular because it resists encroachment from weeds,
has few disease and insect problems, withstands close grazing, establishes
from seed, and does not require high soil fertility. However, grazing
studies indicate that bahiagrass is lower in nutritional value when com- U
pared with bermudagrass or digitgrass. By midsummer protein and digesti-
bility are low, suggesting that animal intake and performance are
adversely affected. In addition bahiagrass is a warm season species
that produces 85% of its annual dry matter from May to October. In spite
of the valuable attributes of bahiagrass its forage quality is low, and
it produces little winter forage. i

An ideal method of overcoming these deficiencies is to manage bahiagrass
with legumes that provide needed quality and biological nitrogen. At
present there are no commercially available perennial legumes adapted to I
south Florida, but ranchers can use a combination of winter and summer
annual species. Florida's summer annual legumes are jointvetch or aeschy- g
nomene (Aeschynomene americana), hairy indigo (Indigofera hirsuta), and
alyce clover (Alysicarpus vaginalis), and the winter species (which act
as annuals in south Florida) are alfalfa (Medicago sativa), red clover
(Trifolium pratense ) and white clover (T. repens).

Since natural reseeding is not always reliable with summer annuals or
impossible with most winter annuals (except Dutch clover), reseeding is a
frequent practice. Establishment by conventional tillage, which involves I
chopping or disking, is expensive and energy intensive. An alternative is
sod-seeding, which Kentucky workers have shown to use only 20% of the
energy input of conventional (prepared seedbed) tillage. However, wide- I
spread use of sod-seeding in Florida has been limited by a low probability
of success in establishment. At the University of Florida's Ona Agri-
cultural Research Center in south Florida considerable research effort
has been devoted to sod-seeding in the past 4 years. We have identified
several reasons why legume stands often fail even when water and fertility
are adequate. 3

Forage legumes are slow to establish, and it is extremely important to
control bahiagrass competition. A grass competes with a developing legume
seedling for light, water, and nutrients: in this order of importance.
Although little is known about the competitive effects for water and
nutrients, we have found that having sufficient light available to legume

SRo S. Kalmbacher is Assistant Professor of Agronomy, Ona Agricultural
Research Center, Ona, Florida 33865.
86 I


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seedlings when they emerge is quite important. Twenty five percent shade
did not inhibit aeschynomene seedling growth, and seedling weight was
equal to that of plants grown in full sunlight, but when 90% of the
light was shaded from aeschynomene seedlings, there was: a 94% reduction
in seedling weight; a 45% reduction in weight from seedlings grown
under 73% light reduction; and a 19% reduction in seedling weight was
found when plants were grown under 55% light reduction.

There are two forms of competition from bahiagrass: 1) competition
from previous grass growth present at the time of seedling emergence;
and 2) competition resulting from new grass growth during seedling
development. Sod management for these forms of competition is different
for winter and summer annual legumes.

Controlling competition before seeding.

Removal of sod cover can be accomplished in several ways, and the choice
may be dictated by economics. Some alternatives are disking, mowing,
grazing, and fire.

When bahiagrass sod was heavily disked and seeded in early December to
red or white clover as compared to drilling seed directly into a thick,
untreated sod, the average dry matter yield of the legumes after 2 years
was 27% lower in the drilled plots as compared to disk and broadcast seeded
plots (Table 1). The number of legume seedlings was 52% higher in the disk
and broadcast plots. In another study aeschynomene yields were also much
greater where bahiagrass was heavily disked as compared to drilling in
untreated grass (1300 vs 600 kg/ha). The reason for the difference was
the removal of the bahiagrass canopy by disking. Since most sod-seeding
drills simply cut a slot in the sod and deposit the seed with a minimum
of disturbance, they do not remove the grass canopy. If a drill is used
or if there is too much cover to allow for a good disking, then some other
sod canopy elimination practices must be used.

Table 1. Comparison of method of seeding on dry matter yield of red and
white clover in bahiagrass sod. Ona ARC. 1977-78.
Year Zip(R) Sod Seeded Disk and Broadcast
----------------kg/ha-------------------
1977 3500 6230
1978 5500 6030
Average 4500 6130


Harvesting excess forage as hay is best, as this justifies cost of mowing
and eliminates the cover. Mowing seems to defeat the purpose of sod-seeding
as it requires more time and energy, and the thatch can result in as much
competition as uncut grass.






88 I


I
Grazing is an excellent alternative, and research has shown that yields
of red and white clover seeded in bahiagrass that had been grazed to
a 5 cm (2 inch) stubble were equal to the yield of legumes seeded in I
a bahiagrass sod which had been burned. Burning has most often resulted
in the best legume stands in our research. Grazing is probably a more I
useful tool for removing sod cover before seeding winter legumes because
after weaning calves in the fall, cows can be concentrated on bahiagrass
until the canopy is removed. In June when summer annuals are seeded,
the nutritional requirement of cows with calves is probably too high to
allow the kind of prolonged bahiagrass grazing which promotes good summer
annual legume growth. When compared with burning prior to seeding, grazing
as a method of canopy elimination resulted in aeschynomene stands and
yields that were comparable. Grazing or disking, followed by broadcasting I
seed resulted in 1500 and 1300 kg/ha, respectively, vs 600 kg/ha for
untreated bahiagrass. 3

Fire is an excellent way to prepare bahiagrass for inter seeding of
legumes. Often a dense bahiagrass canopy can be burned after a frost in
December, but sometimes chemical desiccation is necessary. The herbi-
cide Paraquat(R) has been applied at 0.56 kg/ha (0.5 Ib/A) to kill and
dry out the canopy in order to allow burning. The result was excellent
stands of both winter and summer annual legumes (Table 2). 3

Table 2. Dry matter yield of winter or summer legumes seeded with a
Zip(R) sod seeder in bahiagrass treated with various herbicides.
Ona ARC. 1977-78.

Canopy control
Before After Herbicide Legume yield
seeding seeding treatment Winter annual Summer annual,
------------kg/ha- -------
yes no Paraquat(R) + burn 6640 2970
no yes Dowpon(R) M 3840 2810
no no no herbicide 1310 260 I

SRed and white clover.
t Aeschynomene, hairy indigo, alyce clover. i
Divide kg/ha by 1.121 to get Ib/A.

Burning 12 to 14 cm tall (4.7 to 5.5 inch) bahiagrass resulted in temperatures i
that reached 83 C (182 F) at the soil surface. The value of this heat is
demonstrated in the control of insects and other pests that eat legume I
seedlings. At the Ona ARC a small land snail (Polygyra cereolus) has been
found to be responsible for decimating stands of sod-seeded clovers.
Burning resulted in 98% mortality of this pest, resulting in successful
legume establishment.










Controlling competition after seeding.

Control of sod growth after legume emergence can be accomplished with grazing
or herbicides. Herbicides are valuable for controlling competition after
seeding because they can stop grass growth. When herbicides were applied
to 7 to 10 cm tall (2.8 to 4 inch) bahiagrass in late June, better yields
of summer legumes were obtained as compared to untreated grass (Table 3).
Successful stands of legumes resulted when canopy cover was slight at
seeding and sod control was employed during legume development.

Table 3. Dry matter yield of summer legumes sod-seeded in bahiagrass
treated with various herbicides. Ona ARC. 1977-78.

Legume yield
Herbicide Sod control Aeschynomene Alyce clover Hairy indigo
-----------------kg/ha----------------

Round-up(R) Excellent 4950 5030 1900
Dowpon(R) Good 2920 4130 1380
Paraquat.R Poor 100 970 140
No herbicide Poor 210 450 120

Divide. kg/ha by 1.121 to get Ib/A.

Using herbicides to control competition after seeding winter legumes has
questionable value. Delaying seeding date in south Florida until after
November 15 usually assures that bahiagrass growth will be slowed by cool
temperatures. When night temperatures fall below 15 C (59 F) bahiagrass
growth almost stops. If competition at seeding time has been removed, little
growth will develop after seeding. Hence,with winter annuals it is much
nore important to remove competitionat seeding than to control competition
after seeding.

To demonstrate this point, the canopy was removed at seeding by paraquat and
burning, and the grass canopy regrew slowly, but was unchecked through the
late fall and winter. (Table 2). Excellent yields were obtained from red
and white clover (6640 kg/ha) in this burn treatment, but poorer yields
(3840 kg/ha) resulted in a Dowpon M treatment where the grass canopy
remained at seeding, but all new growth was stopped. Similar summer annual
yields resulted with a burn vs Dowpon M treatment (2970 vs 2810 kg/ha) but
yields produced from untreated grass were poor (260 kg/ha). Both types of
competition control are necessary when sod seeding summer legumes in bahia-
grass, but removing sod cover prior to seeding is most important for winter
legumes.

Sod-seeding machines.

If a good job is done controlling grass competition and adequate fertility
and water are supplied (for winter legumes), then the type of sod-seeding
drill that you use makes little difference in the legume establishment. (Re
have used very simple, relatively inexpensive machines, such as the Zip)







90


seeder; intermediately priced machines, such as the John Deere Powr-till(R)
and Tye(R) seeder; or very expensive, sophisticated machines like the
Bettison 3-D seeder and have had success with all of these. If the practices
for successful establishment are followed, then machine preference is a
personal and economic matter. As pointed out earlier, disking sod and broad-
casting seed can result in good establishment. I

The following are steps recommended for establishing winter or summer annuals
in bahiagrass in south Florida.

Winter annuals (alfalfa, red and white clover).

1. Limit the use of nitrogen on bahiagrass after September 15. Raise
the soil pH to 6.0 for clover and 6.5 for alfalfa.

2. Before seeding graze, remove as hay, or burn off all excess
bahiagrass leaving a maximum of 7.6 cm (3 inches).

3. Inoculate seed with proper strain of fresh Rhizobium and seed
legumes after November 15 to take advantage of cool temperatures
which limit bahiagrass growth. Waiting until November 15, also
increases the chances of rain from cold fronts.

4. Fertilize legumes at seeding with 340 to 450 kg/ha (300 to 400 Ibs/A) i
of 0-10-20 and after the first cutting (about March 15) apply another
340 to 450 kg/ha of 0-10-20. Apply micronutrients if none were
applied in the past 4 years.

5. Irrigate if necessary. Irrigation may be more important with disk
and broadcast methods of seeding than sod drill methods because
of poorer seed-to-soil contact with the former.

6. Bahiagrass growth may be grazed or mowed during legume establishment,
provided seedlings are not clipped.

Summer annuals (aeschynomene, alyce clover, hairy indigo).

1. Limit the use of nitrogen fertilizer on bahiagrass after April 15.
Raise soil pH to 5.5 to 6.0.

2. Before seeding, graze, remove as hay, or burn (after desiccation
with paraquat) all excess bahiagrass, leaving a maximum of 7.6 cm
3 inch).

3. If herbicides are used to control sod growth after seeding, best
results will result if the chemicals are applied 2 to 3 weeks
before seeding so that sod-control is in effect. Dowpon M, especially
if part of a smutgrass control program, is recommended at 2.5 kg/ha
active (3.0 lb/A).

4. Inoculate seed with proper strain of fresh Rhizobium and seed legumes I
after June 15 to increase the probability of favorable moisture
conditions. Seed naked aeschynomene (de-hulled), and for all legumes
it is desirable to use seed rates that are 20 to 25% higher than used


I




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