AGRONOMY

UNIVERSITY OF
FLORIDA
IFAS EXTENSION

Vol. 31:8 August 2007

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IN THIS ISSUE

CORN
Field Tests for N itrate in D brought Stricken Corn ........................................ ......................2
Soybeans After Corn.................... ............. .............................2

COTTON
Potential for C otton ...................................................... ................... 2

FORAGE
Cattle Feed After Drought Stressed Corn .......................................... ............... ........ 2
Summ er Time and Hay Curing in Florida .............................................. ............... 3

WEED CONTROL
Spraying w ith L iquid Fertilizer........................................ ........................................ 3

MISCELLANEOUS
R recent Pesticide B lunders.............. ... .................................. ........ .... ................4
Earn Pesticide Applicator CEUs on Your Own................................................................4

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.

Field Tests for Nitrate in Drought
Stricken Corn

Livestock are sensitive to high nitrates in
grass crops and care should be taken when
grazing summer annual grasses during
drought periods. Nitrates are usually highest
in the base of the stalk and become less as
you get higher on the plant. It may take a
week or longer after rains for the nitrates to
be diluted throughout the plant. Plants that
have died from drought may have high
nitrates in the lower stems; if cut for hay or
silage, this plants with high nitrates need to
be cut at a higher stubble height to avoid
cutting the stem parts with the highest
nitrate concentrations. Plants should be
checked or tested before being utilized after
periods of drought. The nitrate test can also
be used to determine if nitrogen is adequate
for corn growth during the vegetative stage
of growth. Kits to test testing for nitrates in
forages can be found on the web or contact
your local county extension office.

David Wright

Soybeans After Corn

Growers who have irrigation and want to
plant soybeans after corn can do so
successfully. In recent years, maturity group
V soybeans have been planted in mid to late
August in 36" rows with yields of 35 bu/A.
Bean yields can be increased by as much as
25% when more narrow rows are planted.
Planting closer rows makes a more efficient
use of light, nutrients and water. Planting
after late August is probably too late for
good yields; the earlier in August or July that
soybeans can be planted, the higher the yield
potential. Even though years ago we
recommended maturity group VIII soybeans
for late planting, the earlier group (MG V
and VI) seems to mature naturally without a

frost and give good yields when planted late
with adequate height. Cool nights and light
frosts slow down pod fill and yield potential.

David Wright

Potential for Cotton

Even though cotton was slow to germinate
in May and June due to the drought and
growth has been erratic, the potential for a
good crop is still within reach. Usually
cotton planted after the first of July fruits up
well and looks as if it will make a good crop
but seldom does. Cotton planted in the 3rd
week of June has made more than 3 bale
cotton at times in North Florida but cannot
recover from a lot of stress and replanting
would be out of the question if stand failures
occur. The period from emergence to bloom
can take about 60 days. The last effective
bloom date for cotton is usually around the
first week of September. Cotton planted in
April and May emerged over a 6-8 week
period due to the drought. Therefore,
blooming started in late July and will
continue through early August leaving 3-5
weeks of effective blooms. Thus, cotton
could produce a very good boll set and yield
despite the crop not being very uniform
because of the different emergence times in
the same field. Give cotton every chance to
make a profitable yield by protecting blooms
and young bolls from stinkbugs as well
as plant bugs and provide adequate fertility.

David Wright

Cattle Feed After Drought Stressed Corn

Many growers are considering winter
forages to help overcome corn or other feed
sources lost due to drought. However,

millets and sorghum-sudan grasses may be
more of a sure thing and will give growers
forage sooner than fall grazing. These
grasses may be planted after corn that was
mowed down, grazed, or cut for hay or
silage. These grasses may also take
advantage of residual fertilizer made to the
previous crop. Recent rains will help these
crops get off to a good start and they have
high quality. They also germinate and grow
with low moisture conditions compared to
corn. Early planted small grains often have
problems with barley yellow dwarf virus
which stunts and delays forage availability.
Consider using the summer annual forages
and plant them in August. These annual
forages will grow until frost hits.

David Wright

Summer Time and Hay Curing in Florida

The moisture content of fresh forage is
around 75 85%, so getting forage to where
it is dry enough for bailing which is
around 20 % moisture requires removing a
large amount of water. The number of days
to bring the moisture down to 20% is
typically 3 or more. However, you want to
quickly cure your hay because rapid curing
keeps the forage from respiring and
consuming sugars. Once the forage is below
40% moisture the respiration rate is almost
zero. Rapid removal of moisture also helps
in maintaining the green color in the hay as
well as avoiding spoilage due to rain.
Drying of fresh cut forage is affected by
different factors: solar radiation intensity, air
temperature, relative humidity and soil
moisture. Moisture can also move from the
air to the crop when the relative humidity is
very high as is the case when there is dew or
rain occurs. Typical hay production
practices in Florida include 'tedding and
raking'. Tedding disperses or scatters the
forage over the entire field in order to
capture all the solar radiation and use more
efficiently the energy of the sun. Tedding
also makes a thinner layer which produces a

more uniform drying. Usually, tedding
shortens the curing time by about 12 day.
Raking should be done at 35-40% moisture
to keep dry matter losses under 4%. If
raking is done too late (when crop is at
bailing moisture) losses can exceed 20%.
Also, to minimize losses, hay should be
raked in the same direction that it was
mowed.

Yoana Newman

Spraying with Liquid Fertilizer

Many hay producers opt to spray herbicide
in a liquid nitrogen solution (28-0-0, 32-0-0,
etc) so they can fertilize and control weeds
in one pass. This procedure can be a
convenient one-pass solution for two
problems. However, it is possible for
herbicide and liquid N to react with one
another and cause the solution to clabber, or
gel, in the spray tank. To avoid that
situation, here are some things to consider
before using liquid N/herbicide solutions.

1. Not all herbicides are compatible with
fertilizer blends. Read the herbicide
label to ensure that special mixing steps
are not required to improve
compatibility.

2. If in doubt, perform ajar test. Ajar test
is simply when you mix herbicides and
nitrogen solutions together in small
batches prior to adding to the spray tank.
It is important to mix the products in the
same proportions as you plan to spray
and in the proper mixing order. If
incompatibility occurs, it is much easier
if you know this ahead of time and only
have to dispose of 1 pint rather than 400
gallons.

3. As a rule, ester formulated herbicides
(such as Remedy, 2,4-D ester, Outlaw,
etc) are more compatible with liquid N
than other formulations (2,4-D amine,
Milestone, Weedmaster, etc). If using

amine formulations, mix a 50% solution
with water prior to adding to the liquid
fertilizer.

4. Incompatibility is more common with
fertilizers that contain phosphorus,
potassium, or sulfur than with those
containing nitrogen only.

Solutions to incompatibility
Sometimes the jar test indicates that the
herbicide and fertilizer solution are not
compatible. If this occurs, here are a
few possible solutions.

1. Mix the herbicide with water prior to
adding to the fertilizer. This can often
minimize the interaction.

2. Change to a different herbicide
formulation.

3. Use a fertilizer solution that contains
only nitrogen.

4. Add a commercial compatibility agent.

Jason Ferrell

Recent Pesticide Blunders

This past spring semester, a student who was
a national of another country made a
comment to me after our class lecture on
pesticide regulations in the U.S.: "we really
have no laws regulating pesticide use in my
country, and quite often, we have human
deaths attributed to pesticides." I didn't tell
the student, but I was thinking to myself:
"we are highly regulated in the U.S., yet we
still have plenty of accidents, stupid
mistakes, but fortunately very few deaths
attributed to pesticide use."

FDACS keeps me abreast of their pesticide
misuse investigations with emails, on
practically a daily basis, of interesting
encounters from around the state. Some are
unbelievable for whatever reason personal

grudges with malicious intent, mischief
seekers, attempting to maximize pesticide
efficacy, plain ignorance, being in a hurry,
etc. But, I thought that I would share some
of these recent investigative reports. To
summarize several:

* Palm Beach County (July): a pesticide
storage trailer was parked on the side of
the road, broken into, and set afire. The
local fire department responded, put out
the blaze, but herbicides were spilled
and the area subsequently flooded.
* Santa Rosa County (June): a homeowner
while mowing his lawn was drifted upon
by an applicator treating a nearby peanut
field. The report stated that the wind
speed at the time was 30 mph.
* Volusia County (June): a lady's 3 dogs
were found violently ill in her front yard
along with a tainted piece of pork
covered with a blue/green substance.
Their vet postulated the substance to be
rat poison. The dogs subsequently
survived following treatment.
* Jackson County (April): aerial
application of a defoliant applied to a
peanut crop rather than to the intended
cotton crop.

Those are just a sample of some of the more
colorful recent incidents in this state. The
incident that prompted me to write this
article came to me yesterday (July 19) from
a colleague at Washington State University.
This is a horrific human tragedy that
fortunately doesn't happen often in the
United States; nevertheless, was reported by
the Associated Press:

* Lubbock, Texas (July 18): a family in an
attempt to rid their home of cockroaches
used phostoxin in their home. A 2-year-
old girl died and 4 adults were sickened
by the released fumes. Phostoxin is a
fumigant which releases phosphine gas,
and is typically used industrially for
insect control in storage facilities, such
as grain warehouses.

Yes; pesticide use is highly regulated in the
United States, but for obvious reasons. In
Florida, we have stricter regulations than
many states; but, that's not necessarily to
our disadvantage. Our natural resources are
at stake, yet precious to all. Our rapidly
growing population demands and expects a
cleaner and safer environment as well as
their personal protection. With our climate,
pest complexes, and cropping systems, the
need for pesticide use will continue. At the
same time, being a good steward of our
natural resources, family, and neighbors
should be placed at a premium.

Fred Fishel

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[WAS EWim

.4AU CEl am
FD. lC approu

Fred Fishel

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
products.
Prepared by: J.M. Bennett, Chairman IInI, ,,11 ...I J.A. Ferrell, Extension Agronomist i ,,1il, ,,l 1...I F.M. Fishel, Pesticide
Coordinator ( ,.I.I, .i ,,i .I..I Y.C. Newman, Extension Forage Specialist ., ,,-il .Ih, and D.L. Wright, Extension Agronomist
Idl a ifa,.uff.edu I

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