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Agronomy notes
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00066352/00092
 Material Information
Title: Agronomy notes
Uniform Title: Agronomy notes (Gainesville, Fl.)
Physical Description: v. : ill. ; 28 cm.
Language: English
Creator: Florida Cooperative Extension Service
Publisher: Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida.
Place of Publication: Gainesville
Creation Date: September 2007
Subjects / Keywords: Crops and soils -- Florida   ( lcsh )
Crop yields -- Florida   ( lcsh )
Agriculture -- Florida   ( lcsh )
Agronomy -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
periodical   ( marcgt )
serial   ( sobekcm )
Statement of Responsibility: Florida Cooperative Extension Service, University of Florida, Institute of Food and Agricultural Sciences.
General Note: Description based on: January 1971; title from caption.
 Record Information
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: aleph - 000956365
notis - AER9014
System ID: UF00066352:00092


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Vol. 31:9

September 2007

Stl|cilbtr 2Nth 21 Equinie Inqltile jnd Allhed Trade Sho\\. South Ejiciir Lil n stock Pil dion.
Ocala. NlI.ioII Count\
Octolcr 4-5 D;vI D" & Turlk\ Short CoulSe. NREC (?u1H\. FL
Ocollbr 19th (?)ual and Do\ lmlij nlac.nti Short CouIrsi. Arcadia. FL



Fall G rasses (2007) W hat to plant? ........................................................................... 2
Overseeding Winter Pastures ................................................................. ...............2


B oron F fertilization for P eanut ................................................................. ...................... 3
M anganese D efficiency in Peanut........................................... ...................................... 3
P e an u t M atu rity .................................................................................. 3


Soybean R ust Spread in Florida.................................................... ............................... 4
W watch for P alm er am aranth ................................................................... ........................ 4


W heat Planting Inform ation ................................................................... ................... 5

The Institute of Food and Agricultural Sciences (IFAS) 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, age, handicap or national origin. For information on obtaining other extension publications, contact your county Cooperative Extension
Office. Florida Cooperative Extension Service/ Institute of Food and Agricultural Sciences/ University of Florida/ Larry Arrington, Dean.

Fall Grasses (2007) What to plant?

Winter grasses in the state cannot be
recommended in a 'recipe' fashion as they
don't grow in all places and all soil types.
Winter grasses like cereal Rye adapt well to
drier soils but others like ryegrass (cool-
season grass, not a winter grain) require
substantial moisture to grow properly. In
North and North-central Florida ryegrass
and most of the small grains are
recommended. Recommendation for South
Florida is almost exclusively Ryegrass
because of the small window of cold
temperatures; also temperature and disease
pressure are too high to use any of the small
grains for the mid-south and south Florida.
Following are the recommend varieties for
2007 by maturity (early, medium, and late):

Early: FL401 (for early grazing or use in
blends), AGS 104.
Medium: Wrens 96, Wrens Abruzzi,
Pennington Wintergraze 70, and Early
Late: Bates, Oklon.


Medium: Horizon 270, Horizon 321,
Horizon 474, SS76-40, and NK-Coker
Late: TAMO 406

Wheat: Recommended varieties are all
grain types that may be used for forage.

Medium: AGS 2000 and Pioneer 26R61
Medium-late:USG 3592


Early: Gulf
Mid to late: Florlina, Surrey II, Jackson,
TAM 90
Late: Jumbo, Prine, Big Daddy, Passeral

Yoana Newman and Ann Blount

Overseeding Winter Pastures

The small grains and winter forages in
general can be planted on a prepared
seedbed or they can be overseeded into
warm-season pastures. If the decision is to
overseed, your warm-season perennial
pasture (bahiagrass, bermudagrass) needs to
be grazed very short and disked lightly
(barely scratching the soil) one or two
months before planting time (usually after
the first frost and a good rain). Light
disking is recommended in order to open
(without killing) the warm-season sod and
favor germination of the cool-season seed.
After light disking the area, planting should
follow using a small-grain drill (use the
large seed box for small grains, and the
smaller box for your clovers and ryegrass).
Rates for overseeding cereal grains (oats,
rye, wheat) are usually 85-90 lbs/acre, which
is in the lower end of the recommendations
when planting on prepared seedbed; the
recommended seeding depth for cereal
grains is 1 to 11/ inch. When overseeding
ryegrass, the recommended rate is 20-30 lbs
and because ryegrass seed is very small, the
recommended seeding depth is /4 to 12 inch.
Because of Florida sandy soil conditions,
after overseeding drag the area and pack it,

pulling a roller behind, to conserve the
moisture. Fertilization should be made
following the soil test recommendations but
usually one application is done at planting
and two more throughout the season.

Yoana Newman

Boron Fertilization for Peanut

For many years, boron (B) has been
recommended for peanut. However, many
growers forget about it with no apparent
problem. However, soil tests for B in
peanuts are not very accurate so B should be
applied in a couple of the early fungicide
applications at rates of about /4 lb/A for
each application. It does not take a lot of B
for peanuts since the crop will not take up a
total of 12 lb for the entire crop. However,
"hollow heart" of peanut seed can occur and
symptoms have been bad enough to cause
split stems in some year. Both, yield and
grade can be increased with B applications.
B deficiency is more common on sandy,
drought soils. Sources of B fertilizer are
boric acid and sodium borate (Solubor).
With recent rainfall in most peanut areas,
peanuts appear to be 2-3 weeks later than
normal due to stress from drought with
many fields still pegging and filling pods. It
will be very important to stay on schedule
with fungicides to avoid problems with leaf

David Wright

Manganese Deficiency in Peanut

Several fields of peanuts have shown
manganese (Mn) deficiency this year. The
peanut crop will have a golden cast across
the field and usually occurs in areas that
have a high pH and high calcium and
magnesium levels. Critical plant levels are
around 15 ppm during the bloom period.
Deficiencies are most often found in the
sandier fields that are influenced more by
liming. However, deficiencies can be found

in any soil type with high pH levels. Most
deficiencies will occur with a pH above 6.0
but have been observed with a pH as low as
5.8. If deficiencies do occur, apply Mn as a
foliar application. Manganese sulfate is the
form of Mn most often used. Chelated Mn
often does not correct the deficiency for the
season since it is usually around 5% Mn
material and is applied at rates of 1-2
quarts/A. Manganese sulfate should be
applied at rates of 5-10 lbs/A, and can be
applied foliar which reacts more quickly
than soil applications.

David Wright

Peanut Maturity

Determine proper maturity of peanuts by
pod blasting, hull scrape or the shell out
method. County extension faculty often
assists in maturity determination or can
recommend where help can be obtained. It
is important to get the maturity right since
one week either way of optimum maturity
can mean a significant reduction in yield and
grade. Generally, no difference has been
noted in digging and harvesting strip-tilled
and conventionally tilled peanuts. Adequate
soil moisture is required to dig either
properly. Growers who are new to strip-till
often ask: 1) will the residue from the
previous crop interfere with digging? and, 2)
will there be more foreign material in the
harvested peanuts? The answer to both is no.
When peanuts are strip-tilled into cotton
residue, stalks tend to decay slowly due to
their high fiber content. However, with a
cover crop on top of cotton stalks, no
impediments to digging or harvesting have
been noted due to rapid decay. Peanuts have
been strip-till planted into bahiagrass that
was killed in the fall or spring killed, as well
as in corn, sorghum, cotton, and soybean
residue, without any problem during digging
and harvest. Generally, if the strip-till rig
will plant into the residue without any
problems, the peanut plow will not have a
problem in digging. Dry weather can cause

a problem in digging both strip-till and
conventionally planted peanuts. Actively
growing weeds in the crop at digging and
weather conditions cause more problems for
both strip till and conventional planted
peanuts than at planting due to knocking
nuts off vines.

David Wright

Soybean Rust Spread in Florida

Soybean rust has been widespread in late
August of 2005 and 2006. Rust is in several
of the sentinel plots across North Florida
this year. High humidity and rainfall hastens
the spread and spore buildup. The dry
weather that we have had this year has
slowed down the epidemic. Most of the
positive sites that had rust were not
sporulating due to high temperatures so
those nearby fields were not getting
infected. Fungicides may be applied
through R5 growth stage (seed are 1/8th inch
long in pods on one of the four uppermost
nodes) at the time of infection with good
control if the disease is detected early.
Fungicides can be applied with flat fan
nozzles at 10-15 gal/A at 30 psi with very
good control of the disease. Yield increases
of near 30% were noted with two
applications of fungicides applied at first
bloom and either 2 or 3 weeks later.
Fungicides applied after R6 stage (pods are
filled with green seed at one of the four
uppermost nodes on the main stem) are not
expected to increase yields.

David Wright and Jim Marois

Watch for Palmer amaranth

Palmer amaranth has been a troublesome
weed for many years in the west, but has
only recently been introduced into Florida.
Palmer amaranth is in the same family as
redroot pigweed and can easily be
misidentified as such. However, Palmer
amaranth is an extremely aggressive weed

and much more troublesome than redroot
pigweed. To illustrate, soil applied
herbicides such as Prowl or Treflan that are
quite effective on other pigweeds are quite
weak on Palmer. It is common to achieve
only 50 to 60 percent control Palmer with a
preemergence application of Prowl whereas
a similar application would provide
approximately 90 percent control of redroot.
Additionally, Palmer amaranth can grow
over an inch per day and has been shown to
produce as many as 500,000 seeds per plant.
This is compared to much slower growth
rates and 200,000 seeds with other pigweed
species. This incredible seed production
capacity has also led to the rapid
development of resistance to several
herbicides. There are Palmer amaranth
biotypes that have been shown to be
resistant to atrazine, Cadre (and similar
compounds), Treflan/Prowl, and glyphosate.

Currently in Georgia, glyphosate and Cadre
resistance has become widespread (some
populations are resistant to glyphosate,
others are resistant to Cadre, and some
populations are resistant to both). Since the
problem is close to our border, it is essential
that we watch closely for this weed. The
key factors for identifying Palmer amaranth
are the long seed head and petioles. Review
/wfiles/W072.pdf for a more detailed look at
these factors.

Key points

1. If you see Palmer amaranth growing
on your farm, physically remove that
plant before it produces seed.

2. If you intend to employ a custom
harvester, check to see if that picker
has been in Georgia. If so, it will
likely be contaminated with Palmer
amaranth. Palmer seed is extremely
small and virtually impossible to
clean from a picker.

3. If you have Palmer amaranth, treat it
early and often with herbicides. This
weed germinates multiple times
through out the growing season and
can quickly overwhelm a field.

4. Palmer amaranth is nothing like
redroot pigweed. It should be
viewed and treated as the most
aggressive and unforgiving weed in
the Southeast.

Jason Ferrell

Wheat Planting Information

Since wheat prices are near $6/bu and
soybean prices above $8/bu for 2008,

growers may be interested in planting wheat
this fall followed by soybean. Over 150,000
acres of wheat were grown in North Florida
in the 1980's and declined with prices and
the expansion in cotton and peanut acreage.
Choose wheat varieties carefully. Florida's
small grain variety trial information along
with that from Georgia can be found on the
web at www.swvt.uga.edu Those growers
who plan on planting wheat should get the
seed lined up since planting time is from
early November for the longer season
varieties to mid December for the shorter
season varieties. Wheat should be planted at
no more than 2 bu/A of good quality seed to
obtain top yields.

David Wright

The use of trade names does not constitute a guarantee or warrant of products named and does not signify approval to the exclusion of similar
Prepared by: J.M. Bennett, Chairman III., ,,11 ..1,, A. Blount, forage breeder Ii i ,1i,,,,. ,,i ..Ih J.A. Ferrell, Extension Agronomist
I, iII, 1 i, ..I, i J. Marois i n ari. Llfl. edu I Y.C. Newman, Extension Forage Specialist I ... ,,il ..Ih and D.L. Wright,
E 1i,, ,..,, .1 .-- ,,..,,,,- 1 11 1 1, ll H II .I