Front Cover
 Results and discussion

Group Title: Research report - North Florida Experiment Station, University of Florida - 86-1
Title: Effect of tillage and water management on soil-water depletion and grain yield of corn on a sandy soil
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00073720/00001
 Material Information
Title: Effect of tillage and water management on soil-water depletion and grain yield of corn on a sandy soil
Series Title: NFREC, Quincy Research report
Physical Description: 15 leaves : ill. ; 28 cm.
Language: English
Creator: Rhoads, Fred ( Frederick Milton )
Mansell, R. S
University of Florida -- Agricultural Experiment Station
Publisher: Florida Agricultural Experiment Station, Institute of Food and Agricultural Sciences, University of Florida
Place of Publication: Gainesville FL
Publication Date: 1986
Subject: Corn -- Yields -- Florida   ( lcsh )
Corn -- Soils -- Florida   ( lcsh )
Corn -- Irrigation -- Florida   ( lcsh )
Tillage -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
Bibliography: Includes bibliographical references (leaves 14-15).
Statement of Responsibility: by F.M. Rhoads and R.S. Mansell.
General Note: Cover title.
Funding: Research report (North Florida Research and Education Center (Quincy, Fla.)) ;
 Record Information
Bibliographic ID: UF00073720
Volume ID: VID00001
Source Institution: Marston Science Library, George A. Smathers Libraries, University of Florida
Holding Location: Florida Agricultural Experiment Station, Florida Cooperative Extension Service, Florida Department of Agriculture and Consumer Services, and the Engineering and Industrial Experiment Station; Institute for Food and Agricultural Services (IFAS), University of Florida
Rights Management: All rights reserved, Board of Trustees of the University of Florida
Resource Identifier: oclc - 84654867

Table of Contents
    Front Cover
        Front Cover
        Page 1
        Page 2
        Page 3
        Page 4
        Page 5
    Results and discussion
        Page 6
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
        Page 15
Full Text


The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source

site maintained by the Florida
Cooperative Extension Service.

Copyright 2005, Board of Trustees, University
of Florida


NFREC, Quincy Research Report 86-1


SFlorida Agricultural Experiment Stations
Institute of Food and Agricultural Sciences
University of Florida, Gainesville

Effect of Tillage and Water Management on Soil-Water Depletion

and Grain Yield of Corn on a Sandy Soill/

F. M. Rhoads and R. S. Mansell2/

Tillage pans are present in many of the soils of the southeastern U.S. on

which large yield increases of corn have been observed with irrigation. This

raises the question of whether or not benefits would be incurred if both

irrigation and subsoiling were combined. The objective of this experiment was

to determine if corn would respond to subsoiling in the presence of irri-

gation. Water management treatments were applied with and without subsoiling

in a two-year experiment on a Troup sand (Grossarenic Paleudult). Water

management treatments in 1976 consisted of 1) natural rainfall, 2) application

of water.with a trickle system when soil-water pressure (SWP) at the 15 cm

depth reached -0.01 MPa and 3) -0.02 MPa. In 1977, natural rainfall was

compared with irrigation from a sprinkler system when SWP reached -0.015 MPa

at the 15 cm depth. One-half of the plots were in-row subsoiled to a depth of

45 cm both years.

Irrigation significantly (P < 0.01) increased grain yield of corn each

year with widely varying rainfall distribution between years. Subsoiling

in-row increased yield significantly (P < 0.01) with irrigation, only when

rainfall was sufficient to cause downward movement of plant nutrients. Yield

increase from irrigation ranged from 0.5 to 1.5 Mg/ha (7.8 to 23.8 bu/A) in

1/North Florida Research and Education Center Research Report 86-1.

?/Professors of Soil Science, North Florida Research and Education Center,

Quincy, and Department of Soil Science, Gainesville, respectively. University

of Florida.

1976. The average response to subsoiling in 1976 was 1.4 Mg/ha (22 bu/A).

Irrigated plots produced about 10 times as much grain as non-irrigated plots

in 1977 but there was no response to subsoiling. Subsoiling in-row reduced

soil strength and increased soil-water depletion in the 30 to 60 cm depth


Additional index words: Subsoiling, Soil strength, Maize, Zea mays L.,


Effects of subsoiling on crop yield under irrigation have not been studied

extensively because subsoiling is generally considered a dry-land farming

practice to increase root depth and available water for crop plants. Grain

yield of corn was increased in two out of 14 experiments by subsoiling in

Illinois from 1955-57 while no yield increases were observed at eight

locations in Iowa (4). The absence of response was attributed to annual soil

freezing to considerable depth which would tend to minimize traffic pan

development. Tillage pans have been identified and characterized in some of

the Coastal Plain soils occurring throughout the southeastern United States

(3). New Jersey studies using subsoiling on a Collington sandy loam soil did

not show significant yield increases of several vegetables (2). Subsoiling

increased soybean yields in seven of 16 experiments in Georgia (5). In-row

subsoiling increased seed cotton yields as much as 41% in Georgia (1).

Soybean yields were consistently increased in a 3-year Florida study by in-row

subsoiling on a Coastal Plain soil (Orangeburg loamy sand) where a tillage pan

had developed (7). Rainfall amount and distribution were observed to

influence the response of crop yield to subsoiling in earlier studies in

Florida (9). Maintaining high soil-moisture levels in the plow layer with

irrigation was effective in increasing corn yields on a variety of soil types


Variability of crop response to subsoiling between locations and soil

types indicates that tillage recommendations should be based on research

conducted under local conditions. The objectives of this experiment were to

compare the yield response of corn grown on a Troup sand (Grossarenic

Paleudult) to in-row subsoiling with and without irrigation, to measure the

effect of subsoiling on soil strength and to determine the effect of


irrigation and subsoiling treatments on soil-water depletion.


Pioneer brand '3369A' corn was planted March 18, 1976 and Funk's 'G-4507'

corn was planted March 29, 1977. Two seeds per hill were planted by hand and

thinned after emergence to a population of 71,700 plants/ha ( 29,000

plants/A). Row spacing was 91 cm with distance between plants approximately

15 cm. Plot rows were 7.6 m long in 1976 and 6.1 m long in 1977 with four

rows per plot each year. Two center plot rows were harvested, starting about

0.6 m from each end of plots to minimize border effects, for grain yield.

Grain yields are reported at 15.5% moisture content.

A total of 336 kg/ha of N, 98 kg/ha of P, and 279 kg/ha of K were applied

each year. Fertilizer was applied each week in amounts shown in Fig. 1. Rate

of application was increased during the first 8 weeks of growth in 1977 as

compared with 1976 because of slight chlorosis observed in 1976. Fertilizer

application was completed in 12 weeks in 1977 rather than 14 as in 1976.

Three water management treatments were imposed in 1976: natural rainfall,

irrigated when soil-water pressure reached -0.01 MPa at 15 cm depth, and

irrigated when soil-water pressure reached -0.02 MPa at 15 cm depth. Two

water management treatments were applied in 1977 as follows: natural rainfall,

and irrigated when soil-water potential at 15 cm depth reached -0.015 MPa.

Trickle irrigation was used in 1976 and sprinkler irrigation in 1977. Two

tillage treatments were applied each year within each water management

treatment: conventional tillage consisting of disc harrowing to provide a weed

free seed bed, and conventional tillage plus subsoiling in-row to a depth of

45 cm.

Soil resistance to penetration was measured with a C-700 pocket penetro-

meter. Holes 30 cm in diameter were dug in the row and penetrometer readings




= 80



2 4 6 8 10 12

Weeks After


Accumulative percentage of fertilizer applied to corn in
weekly amounts (total N, P, and K) for the growing seasons
of 1976 and 1977.

Time (Days)
Rainfall and irrigation distribution for
and 1977. Day 0 was the planting date:
March 29, 1977.

corn plots in 1976
March 18, 1976 and

Figure 1.

Figure 2.

(PR) were taken horizontally at 5 cm depth intervals to a depth of 45 cm.

Penetration measurements were taken in the same location and direction of the

slot made by the subsoiler. Soil resistance values are based on a regression

analysis of readings taken from the same field location with a cone type

penetrometer versus the C-700 pocket penetrometer rather than the factory

calibration values of the pocket penetrometer (8).

Tensiometers with mercury manometers were installed at 15, 30, 60, and 90

cm depths in one plot of each treatment in both years.

A split plot experimental design with water management as main plots and

tillage as sub-plots was used in 1976, while a randomized complete block

design was employed in 1977. There were four replications each year. Appro-

priate statistical analysis were made to evaluate the data.

Rainfall amount and distribution were extremely different between 1976 and

1977 (Fig. 2) from 0 to 110 days after planting each year. Plots irrigated

when soil-water pressure (SWP) declined to -0.02 MPa received 6 irrigations

(total of 6.9 cm) in 1976 and plots irrigated at a SWP of -0.01 MPa received

17 irrigations (total of 17.2 cm). An extreme dry season occurred in 1977 and

28 irrigations (total of 44.8 cm) were required to maintain SWP above -0.015

in irrigated plots at the 15-cm depth. Total rainfall for the 110 day growing

seasons in 1976 and 1977 was 56.8 and 26.2 cm, respectively.

Tensiometer readings at 41 days after planting in non-irrigated plots

indicated that corn roots were extracting water at the 30 cm depth to a

greater degree in subsoiled plots than in non-subsoiled plots (Fig. 3). Water

extraction at the 60 cm depth was considerably greater in subsoiled plots 48

days after planting. Subsoiling made very little difference in water

extraction at these depths in irrigated plots. Similar results were observed


0 -0.02



60 1





)f I I / /'/ 1 I ) / I / 1


II Subsoiled

ezZ Check


9 oEEz

48 Days]

Soil-water pressure values as affected by subsoiling at
four depths in non-irrigated corn plots 41 and 48 days
after planting in 1977.



Figure 3.


e I/ // // / // //// /Y 11 1117




both years.

Penetrometer resistance versus soil depth indicated that the traffic pan

was located in the 15 to 25 cm zone (Fig. 4). However, data from subsoiled

plots showed soil resistance to be relatively low in the slot made by the

subsoiler throughout the growing season. Conventional tillage following

harvest increased soil strength in the subsoiled slot a considerable amount

(Nov. 15 date). Soil strength was the same in subsoiled as non-subsoiled

plots at the end of the second growing season after subsoiling (data not

shown). Kashirad et al. (3) reported that root growth was drastically reduced

in several Ultisols when PR was greater than 20 kg/cm2

Grain yield response to irrigation (averaged over tillage treatments) was

significant (P < 0.01) with water applied at -0.01 MPa SWP in 1976 (Table 1).

The highest single treatment yield was 10.0 Mg/ha (159 bu/A) which resulted

from in-row subsoiling and irrigation at-0.01 MPa SWP. In-row subsoiling

increased yield from 1.1 to 1.6 Mg/ha with or without irrigation with an

average increase of 1.4 Mg/ha (22 bu/A). Yield was not increased by

subsoiling in 1977 where irrigation was applied (Table 2). Grain production

under irrigation without subsoiling was 10.0 Mg/ha (160 bu/A) and with

subsoiling 10.2 Mg/ha (163 bu/A). Irrigated plots produced about 10 times as

much grain in 1977 as non-irrigated plots. Efficiency of irrigation water

measured in terms of kg of grain/ha-cm was about 2.5 times greater in 1977

than in 1976. Irrigation efficiency was 81 kg/ha-cm (3.3 bu/A-in) for the

-0.02 MPa treatment and 78 kg/ha-cm for the -0.01 MPa treatment in 1976.

Efficiency in terms of grain per unit of water input in 1977 was 205 kg/ha-cm

(8.3 bu/A-in) of irrigation water applied at -0.015 MPa SWP and averaged about

36 kg/ha-cm of rainfall with no irrigation. Total water input efficiency

(including rainfall and irrigation) in 1977 was 143 kg/ha-cm (5.8 bu/A-in).




Resistance (kg/cm2)




E 20
o 30


Figure 4.

Penetrometer resistance in subsoiled and control plots in June and
November of 1976.


Maximum yield under irrigation was approximately 10.0 Mg/ha each year which

shows the possibility of maintaining consistent yield levels from year to year

on sandy soils with extreme variation in rainfall by using appropriate water

and nutrient management practices.

Table 1. Effect of irrigation and tillage on grain yield of corn in 1976.

Tillage none -U.U2 MPa -0.01 MPa Average


Conventional 7.3 7.8 8.8 8.02/

in-row-subsoil 8.7 9.4 10.0 9.4

Average 8.1a 8.6ab 9.4 b/

1/Irrigation (1.3 cm of water per application) applied with drip system when
soil-water pressure reached specified value at the 15 cm soil depth.

LSD.01 (tillage) = 1.1 Mg/ha.

/Means followed by same letter are not significantly different according to
Duncan's Multiple Range test (P = .01).

Table 2. Effect of irrigation and tillage on grain yield of corn in 1977.

Irrigation 1/
Tillage None -0.015 MPa-/


Conventional 0.7 10.0

in-row-subsoil 1.2 10.2

/ Irrigation applied with sprinkler system when soil-water pressure at 15 cm
depth reached -0.015 MPa.

Wilt ratings in the rainfall plots taken during the first half of the 1977

growing season indicated that plants in subsoiled plots were not stressed as

much as plants in conventional tilled plots. However, during the last half of

the season plants in subsoiled plots were as severely stressed as those in

conventional tilled plots. Severe drought occurred during 1977 rendering

subsoiling ineffective for increasing crop yield on the Troup soil.

Subsoiling can compensate to some extent for poor rainfall distribution and

slightly deficient amounts but not for extremely low amounts. The increase in

yield (Table 2) from 0.7 to 1.2 Mg/ha with in-row subsoiling and no irrigation

was not significant (P < 0.10) because of a large standard deviation in the

subsoiled treatment.

Response to subsoiling in irrigated plots during 1976 might be attribu-

table to recovery of nutrients that moved below the traffic pan as a result of

excessive rainfall between 40 and 80 days after planting. Plants in subsoiled

treatments may have recovered more of these nutrients because of deeper

rooting (Fig. 3). Rainfall and irrigation were not applied in sufficient

amounts to cause leaching of plant nutrients in 1977 (Fig. 2). Two cm of

irrigation did not increase the soil-water content at the 60 cm depth (Fig.

5). After 7 hours soil-water content was highest at the 15 cm depth following

irrigation. Tensiometer data in Fig. 5 indicate that less than half of the

applied water (2 cm) penetrated to the 30 cm depth. Since rainfall or

irrigation did not exceed 2.5 cm for any 3-day period during the growing

season until about 100 days after planting, less than half of the water

soluble nutrients could have moved below the 30 cm depth. Rooting depth had

reached 30 cm by 48 days after planting in non-subsoiled plots (Fig. 3).

In conclusion, irrigation significantly increased grain yield of corn on a

Troup soil in two consecutive years even though rainfall distribution varied

widely between years. Subsoiling in-row increased yield when rainfall was

sufficient to cause downward movement of plant nutrients. Subsoiling in-row

15 30 60 90
0 0 70 -0 70 7

-0.005 1 \

I I\

-0.010 /
1 \


Soil-water pressure distribution with depth before
irrigation and 0, 1.5, 3, and 7 hours following 2
cm of sprinkler irrigation in 1977.




Figure 5.

reduced soil strength and increased soil-water depletion in the 30 to 60 cm

zone according to tensiometer data. The combination of in-row subsoiling and

irrigation increased yields significantly in a year with leaching rainfall,

but subsoiling did not increase yields on irrigated plots when rainfall was

extremely low. Under rainfed conditions, subsoiling would appear to be of

greatest benefit when the crop experiences slight to moderate levels of stress

on this soil with a low water holding capacity.


1 Boswell, F. C., D. A. Ashley, 0. L. Brooks, G. W. Bird, T. D. Canerday, J.

G. Futral, R. S. Hussey, C. E. Perry, R. W. Ronadori, and J. S.

Schepers. 1977. Influence of subsoiling, liming, a nematicide, and

soil bedding on cotton yield in 'stunt' areas of Georgia. Agri. Exp.

Sta. Univ. of Ga. Res. Bul. 204.

2 Brill, G. D. R. B. Alderfer, and W. J. Hanna. 1965. Effects of sub-

soiling and deep placement of fertilizer on a coastal plain soil and

vegetables. Agron. J. 57:201-204.

3 Kashirad, A., J. G. A. Fiskell, V. W. Carlisle, and C. E. Hutton. 1967.

Tillage pan characterization of selected coastal plain soils. Soil

Sci. Soc. Am. Proc. 31:534-541.

4 Larson, W. E., W. G. Lovely, J. T. Pesek, and R. E. Burwell. 1960.

Effect of subsoiling and deep fertilizer placement on yields of corn in

Iowa and Illinois. Agron. J. 52:185-189.

5 Parker, M. G., N. A. Minton, 0. L. Brooks, and C. E. Perry. 1976.

Soybean response to subsoiling and a nematicide. Agri. Exp. Sta. Univ.

of Ga. Res. Bul. 181.

6 Rhoads, F. M., and R. L. Stanley, Jr. 1975. Response of corn (Zea mays

L.) grown on soils of three textural classes to plow layer water

management. Soil and Crop Sci. Soc. of Fla. Proc. 34:1-3.

7 Rhoads, F. M. 1978. Response of soybeans to subsoiling in North Florida.

Soil and Crop Sci. Soc. of Fla. Proc. 37:151-154.

8 Rhoads, F. M. 1982. Soil resistance to penetration: a comparison between

two types of soil penetrometers. Soil and Crop Sci. Soc. of Fla. Proc.


9 Robertson, W. K., J. G. A. Fiskell, C. E. Hutton, L. G. Thompson, R. W.

Lipscomb, and H. W. Lundy. 1957. Results from subsoiling and deep

fertilization of corn for 2 years. Soil Sci. Soc. Am. Proc.


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