AGRONOMY
UNIVERSITY OF
FLORIDA NOTES
IFAS EXTENSION
February, 2005

IN THIS ISSUE

CORN
Row Spacing and Plant Populations for Corn ............................ 2

COTTON
Cotton Variety Selection ... .......................................

FORAGE
Bermudagrass Establishment -Time of Planting ...........................
Best M management Practices for Pastures ..............................
Cover Crops for Strip Tillage ......................................
Dairy Producers When to Harvest Small Grains for Forage .................
Feeding Hay to Horses .........................................
Forage Quality Terms and Definitions................................
Grazing Management of Perennial Grasses in Late Winter ..................
Hay Producers Prepare for the Coming Season ........................

PEANUTS
Incorporating Yellow Herbicides: Mechanical vs. Irrigation? ................
Peanut Inoculants ...................................................

TOBACCO
T tobacco C contracts .. ............................................

MISCELLANEOUS
Lime Applications to Row Crop Land ...................................
N itrogen Supplies .. ............................................
Report of 2004 Agronomic Crop Production ................. ...........

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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, Interim
Dean.

Row Spacing and Plant Populations for
Corn

Corn is more susceptible to stress than many
crops since it has such a short pollination
period and that period should be as free of
water stress as possible. Many growers are
interested in looking at different row
spacing and plant population, but should
consider what other factors are limiting if
irrigated corn is producing only 140-160
bu/A. When yields get into the 190-220
bu/A range on a consistent basis fine tuning
the plant population and row spacing can
help boost yield. The higher the plant
population and the more narrow the row, the
more stress that will be encountered for
water and nutrients and standability.

DLW

Cotton Variety Selection

A high percentage of the Florida cotton crop
will be planted to a single variety in 2005.
This variety, DP&L 555 is susceptible to
root knot nematode and caution should be
taken if cotton is to be grown in fields where
serious nematode levels are known to exist.
Rotation, recommended nematicides, proper
fertilization and water, and more resistant
varieties are a way to overcome the effects
of high nematode levels in these fields.

DLW

Bermudagrass Establishment -Time of
Planting

The improved hybrid bermudagrasses do not
produce sufficient seed and must be
established from vegetative plant parts. Dug
sprigs, consisting of underground rhizomes,
plant crowns and stolons can be planted

from mid-February through July. Sprigging
bermudagrass in mid to late winter before it
starts growing (before breaking dormancy)
is encouraged. Sprigs dug in early spring
after the plants have broken dormancy have
lower levels of energy reserves. Energy
reserves are needed to initiate and develop
new shoots (sprouts). Also, soil moisture is
usually more favorable in late winter as
compared to spring (April-May). In the
spring, when top growth reaches four to six
inches, digging and planting of sprigs should
be delayed until after the first hay harvest or
harvest of tops for planting. Tops (green
stems) can be planted in June and July. The
grass should be overly mature with six
weeks or more of growth when the tops are
harvested for planting. (-source Florida
Forage Handbook)

CGC

Best Management Practices for Pastures

"On bahiagrass pastures nitrogen is applied
in relation to intensity of use, but generally
50 to 60 pounds of nitrogen/acre should be
applied in late winter. This time correlates
with a period of low to moderate rainfall and
nitrogen fertilizer is least likely to be
washed into surface waters. It is also the
time ranches are most in need of forage.
Other perennial grasses may need nitrogen
in late winter and at other times through the
year based on IFAS recommendations."

"Timing of Nutrient Application: To avoid
nutrient losses through runoff, apply
fertilizers during times with the least
potential for leaching or surface runoff
Refer to the water budget (provided by
NRCS) for your county to determine the
times when the lowest potential for nutrient
losses from rainfall occur. Time nutrient

applications so that they coincide as closely
as possible with periods of plant growth and
nutrient uptake."

"Optimize Nutrient Uptake: Maintain proper
soil pH for optimum utilization of applied
nutrients, while preventing toxic effects
from other accumulated elements, such as
copper. The pH recommendations are
published in Univ. of Florida, IFAS Fact
Sheet # SL-129."

"Prevent Nutrient movement off-site:
Include erosion control practices to
minimize soil loss and runoff that can carry
dissolved and soil-borne nutrients to surface
waters. Filter strips along streams are very
effective in reducing the levels of suspended
solids and nutrients.

Try to prevent spreading fertilizers in
ditches as this is a means of movement off-
site. Also, plan fertilizer loading sites away
from ditches and canals where spills can
contaminate the water."
[Source: Water Quality Best Management
Practices for Cow/Calf Operations in
Florida; June 1999.]

CGC

Roundup 3-4 weeks ahead of planting and
result in covers that are 2-3 feet tall to strip
till into.

DLW

Dairy Producers When to Harvest Small
Grains for Forage

Forage quality of small grains (oats, wheat,
rye, triticale) generally decreases as they
mature from the boot to the dough stage.
Lignification of the stem tissue ( the stem
becomes more woody) appears to be the
main reason for reduced digestibility of the
forage. If the forage is to be fed to high-
producing dairy cows, it is suggested that
the small grain crop be harvested at the
boot-stage when it will have a feed value
close to that of top quality alfalfa. Since
small grain crops harvested at the dough
stage produce the most digestible nutrients
and protein per acre, it is recommended that
the crop be harvested at the dough stage if
the forage is intended for animals that do not
require top quality forage.

CGC

Feeding Hay to Horses

Cover Crops for Strip Tillage

Early February is a good time to apply
nitrogen fertilizer to cover crops along with
2,4-D to kill winter broadleaf weeds and
stimulate small grain or ryegrass cover
crops. About 30-40 lbs/A of nitrogen will
stimulate grass growth and shade further
development of weeds. Grasses without
weeds are easier to kill with materials like

Before feeding, inspect hay for dust, mold,
or other contaminants. Moldy hay should
never be fed to horses as they may develop a
respiratory allergy to the hay. The most
severe form of this problem is referred to as
chronic obstructive pulmonary disease, or
heaves. Horses with heaves suffer
permanent lung damage. These horses are
usually unable to be exercised and thus are
not useful for many physical activities.

Symptoms of heaves (coughing, difficulty
breathing) may be minimized by controlling
dust and mold in a horse's environment.
Three common management techniques
include good ventilation, soaking hay in
water to prevent dust, and using hay cubes
instead of long hay as a forage source.

Hay may be fed in racks or tubs, or it may
be placed on the ground. Putting hay in a
rack or a tub usually reduces waste,
especially when groups of horses are fed
together. When hay is fed on the ground to
a group of horses, 20-40% of the hay may be
wasted. Waste will be greater with late-
maturity grass hay that is low in palatability.
When alfalfa is fed on the ground, leaf loss
may be high. This is significant because the
leaves contain the most nutrients. When
using hayracks or mangers, be sure they
allow enough space for all horses in an
enclosure to eat comfortably at the same
time. If there is inadequate space, some
horses will be excluded or injuries may
occur as they compete for space. The rack
or manger should be placed in a location
that allows safe and easy access for horses
and humans. Hay racks that tip over easily
are unsafe, as are feeding devices that horses
can jump into (such as some cattle feeders).
Hay feeders must be cleaned regularly to
prevent the buildup of material that can
mold when wet.

Large round bales may be used for horses
under some circumstances. Unless they are
placed in a feeder, the amount of waste from
a round bale may be relatively high (up to
40%). Large round bales that have been
stored under cover are safe to feed if they
are mold free. Bales that have been stored
outside may be used if the outer, weather
damaged layer is first removed. Twine or
netting must also be removed. Round bales
are most effective for feeding large groups

of horses where the hay is consumed
rapidly. Round bales that stay in the
paddock for several days are likely to
become wet and moldy.

When hay is fed in pasture or paddock to
several horses at the same time, it is helpful
to group horses by physiological state. This
will allow the appropriate matching of the
nutrient needs of the horses to the amount
and quality of forage offered. For example,
if a 600-lb idle pony and a 1200-lb pregnant
mare are allowed access to the same hay, it
is likely that either the pony will be overfed
or the pregnant mare will be underfed. In
most situations, very high quality alfalfa hay
should not be fed free choice. Because it is
highly palatable and nutrient dense, free
access often results in obesity in horses with
moderate to low nutrient requirements (most
horses kept for recreational purposes). A
better hay choice for these horses would be
full bloom alfalfa hay or an alfalfa-grass
mix.

Source: "Alfalfa, The high-quality hay for
horses". By, Glenn E. Shewmaker, Dan
Undersander, Laurie M. Lawrence, Garry D.
Lacefield. (Sponsored by) National Alfalfa
Alliance. www.alfalfa.org

CGC

Forage Quality Terms and Definitions

Laboratories analyze forages by chemical
analyses or near infrared reflectance (NIRS)
methods. A forage test typically includes
measurements of moisture, crude protein,
acid detergent fiber, and total digestible
nutrients. Each term is defined below:

Moisture Hay moisture content is
important because the higher the moisture

content, the lower the dry matter and
nutrient contents per pound of feed. A high
moisture content (above 15%) increases the
likelihood of mold damage during storage.

Crude Protein (cp) Determined by
measuring the nitrogen content of the
sample and multiplying by 6.25, since
protein in forages contains about 16%
nitrogen. The general quality of hay is
closely associated with crude protein, and
both are related to stage of maturity and
leafiness.

Acid Detergent Fiber (ADF) ADF is the
percentage of highly indigestible plant
material present in the forage. It contains
cellulose, lignin, and silica. ADF is a useful
predictor of energy and digestibility of
forages. Low ADF values mean higher
energy value and digestibility, therefore low
ADF values are desirable.

Neutral Detergent Fiber (NDF) NDF
represents all of the structural or cell wall
material in the forage. NDF is partially
available to animals. NDF is closely related
to animal intake of the forage: as NDF
increases, intake decreases. Like ADF, low
NDF values are desirable.

Total Digestible Nutrients (TDN) TDN
represents the total of all digestible nutrients
in the forage. It may be the sum of
measured quantities or less accurately
estimated from ADF.

Source: "Alfalfa, The high-quality hay for
horses". By, Glenn E. Shewmaker, Dan
Undersander, Laurie M. Lawrence, Garry D.
Lacefield. (Sponsored by) National Alfalfa
Alliance. www.alfalfa.org

CGC

Grazing Management of Perennial
Grasses in Late Winter

Most of our improved perennial pasture
grasses need extra attention in late winter
and early spring. When warm weather
arrives, these grasses need time to grow new
roots and rebuild energy reserves in the
crown and roots. Allowing the plants to
rebuild and attain a healthy condition
permits them to better withstand any stress
that might come along during the remainder
of the growing season.

In some pastures, the grass will have been
grazed down to the ground by mid February
or earlier. Although bahiagrass can
withstand a certain amount of overgrazing,
other grasses cannot. When warm weather
arrives and the grass starts to regrow, cattle
should be removed from these pastures and
kept off until the grass has fully recovered.

Floralta and Bigalta Limpograss
(hemarthria) are susceptible to overgrazing,
especially the Bigalta cultivar. Therefore,
cattle should be removed from these
pastures once they are grazed down during
the winter. Cattle should not be put back in
until the regrowth is 14 to 16" tall. Then
rotational grazing can be started with cattle
being removed when the grass has been
grazed to an 8" stubble height.

If grazed close during the winter, Pangola
and the other digitgrasses should also be
allowed to regrow to a height of 10 to 12".
Rotational grazing can then be started with
cattle being removed from a pasture
(rotated) when the grass has been grazed
down to a height of 4 to 6". In mid-summer,
these pastures need a minimum of one week
and preferably three weeks rest between
grazing periods. Three to four weeks of rest

between grazing periods is needed before
and after mid-summer.

Allow stargrass to regrow to a height of 10
to 14" and then graze back to a 5" stubble
before rotating cattle. If grazing is needed
before the desired height is reached, follow
the old rule of thumb "take half, leave half."

In general, it is always desirable to have
pasture size and cattle numbers adjusted so
that a pasture can be grazed off in one week
or less.

CGC

Hay Producers Prepare for the Coming
Season

Burn frosted bermudagrass stubble to reduce
spittlebug infestation, certain fungal
diseases, remove trash and kill early
germinating winter weeds. Burning also
seems to allow the sun to warm the ground
and stimulate growth. Do not burn to soon.
Wait until a few green shoots are present,
indicating that the bermudagrass is breaking
"dormancy". If a hard freeze follows
shortly after growth is stimulated, the stand
could be damaged. This is especially true
for a non-cold tolerant bermuda such as
Coastcross 1. Coastal and other
bermudagrasses that have rhizomes have
greater cold tolerance and will likely survive
a hard freeze.

Study soil tests and consider last years
growth. Are there areas in the field where
growth appeared to be reduced or where the
stand is thinning? Bermudagrass uses a lot
of potassium and over time there may be
excessive "drawdown" of the potassium in
the soil profile if only minimal amounts
have been applied. Thinning of the stand is
a common symptom of insufficient
potassium.

Fertilize the new growth with 80 pounds of
N per acre and the soil test recommended
amounts of potassium and phosphorus.

Be prepared to control winter weeds in the
first growth period if needed. Burning will
kill many of the weed seedlings, but a
herbicide may be needed to kill weeds that
escape the fire or that germinate later. Try
to kill these weeds early so that they will
have enough time to dry and disintegrate
before the first harvest is taken.
CGC

Incorporating Yellow Herbicides:
Mechanical vs. Irrigation?

Prowl and Sonalan have been successfully
applied preplant incorporated (PPI) for weed
control in peanuts for many years. Recently,
the labels of these products were changed to
allow preemergence (PRE) applications as
long as rainfall or irrigation occurred in a
timely manner for incorporation. It has been
well documented that PPI applications are
more effective than PRE applications under
dry conditions. However, I have no doubt
that PRE applications can be equally as
effective as PPI when they are activated by
rain or irrigation within a short time period.

The biggest problem with traditional PPI
applications is the lack of consistency with
the various tillage implements that are used.
Some have used incorporation with great
success, but others have not. It is very easy
to incorporate too deeply. This dilutes the
herbicide in the soil and sufficient
concentrations will not be present for season
long weed control. Using water instead of
steel will consistently result in a more
uniform incorporation.

Research has shown that there are no
differences in weed control or peanut yield
in response to incorporation method of

Prowl or Sonalan. An additional benefit of
using water instead of tillage to incorporate
herbicides is the fact that water is cheaper.
The estimated cost of using mechanical
incorporation methods ranges between $8.50
and $12.96/A while the estimated cost of
applying a herbicide and incorporating with
0.75" of water, using a center-pivot
irrigation system, is $6.48/A.

The bottom line, we expect no difference in
performance between traditional PPI
herbicide applications and PRE applications
followed by a timely irrigation (0.5-1.0" of
water within 48 hours after application).
However, this does not mean that I am
against the use of mechanical incorporation.
Herbicide incorporation with tillage has
served agriculture well over many, many
years. The use of water as an incorporation
tool simply gives producers more flexibility
in their application of these herbicides.

JAF

Peanut Inoculants

Being a legume, peanuts that are well-
nodulated generally have adequate nitrogen
available for vine growth and pod
production and thus no fertilizer nitrogen is
needed. The nitrogen is supplied by the
symbiotic relationship between the plant and
the bacteria in the nodules that can convert
atmospheric nitrogen into a form usable by
the plant. These bacteria normally survive
in the soil over a number of years after well-
nodulated plants have grown in the field.
The strain of bacteria that can nodulate
peanuts, is also effective in nodulating a
number of other legume plants, such as
cowpeas, Florida beggarweed, alyce-clover,
hairy indigo, and others. Consequently
there may be an adequate population of
bacteria in the soil to cause nodulation and
nitrogen fixation by the peanuts and there

would be no response to artificial
inoculation. On the other hand if peanuts or
other appropriate legumes have not grown
on the field in recent years, it would be well
to consider the use of added inoculants at
planting. Cleared timber land areas or grass
pastures that have a dense sod and are to be
planted to peanuts would be likely
candidates for use of artificial inoculants. A
native legume, partridge pea, may be present
in wooded areas, but plants are usually
scattered, which would result in a similar
pattern of nodulated peanuts if only natural
inoculation is available.

There are three methods of artificially
inoculating peanuts with the nitrogen-fixing
bacteria, with the cost of the inoculant being
about $10 or less per acre for any of the
them. The most simple method is sprinkling
a peat-based powder inoculant on the seed at
or just before planting. While this method is
most common with soybeans and forage
legumes where the seed and inoculant can
be vigorously mixed, peanut seed are
somewhat fragile requiring very gentle, if
any, mixing. Also peanut seed usually have
a fungicide applied to them by the seed
company and mixing the treated seed with
an inoculant could result in decreased
protection from diseases. The powder
inoculant is usually sprinkled over the
peanut seed in several layers when it is
being placed in the seed hoppers on the
planter. Bulk seed handlers may have
mechanical inoculators that would reduce
the time required to inoculate seed. Getting
uniform application of the inoculant on the
seed is imperative.

The second method of applying inoculants
would be to use a granular formulation that
is placed in the seed furrow with a granule
applicator at planting. Since it is likely that
a set of granule applicators would be used to
apply the insecticide Thimet, a second set of

granule applicators would have to be
installed on the planting equipment.
Granular inoculants should not be mixed
with other granules because they contain
moisture and probably would not be of
comparable size to other granules, which
would make it impossible to calibrate for
uniform application of either granule.

Liquid inoculants are the third formulation
that could be used. To apply the liquid
material, an adapted sprayer, anhydrous
ammonia applicator, or other suitable
equipment to apply a liquid directly into the
seed furrow would be needed. After the
application equipment has been installed and
calibrated, the liquid would probably require
less labor during application than the other
formulations. It is difficult and usually
futile to apply the inoculant after planting.

If for some reason the peanuts are not
nodulated, the foliage will be yellow and
vine growth retarded, which are simply
symptoms of nitrogen deficiency. To
relieve these symptoms, a broadcast
application of a nitrogen fertilizer, such as
ammonium nitrate would be effective.
Observations indicate that about 50 pounds
of nitrogen per acre would restore the green
color and stimulate vine growth.

EBW

Tobacco Contracts

The Flue-Cured Tobacco Stabilization Coop
is offering exclusive as well as non-
exclusive agreements to growers. The
exclusive contract requires that the grower
sell all of his tobacco through a marketing
center operated by the cooperative. The
non-exclusive contract would permit the
grower to sell tobacco that may be refused
or production that is in excess of the primary
contract with the companies. By

participating in the cooperative's programs,
the grower is assured of continued
membership in the organization. Further
information on the Stabilization plans can be
found at their web site.

EBW

Lime Applications to Row Crop Land

If lime has not been applied to row crop land
prior to this time of the year, apply in
needed amounts to allow it to start reacting
with the soil for crops to be planted later in
the spring. Many other nutrients have better
uptake by the crop when the pH is in the 5.8
to 6.2 range.

DLW

Nitrogen Supplies

From all indications, nitrogen may be in
short supply and cost more than in previous
seasons. High natural gas prices and
competition have resulted in higher nitrogen
prices and hauling costs are higher too.
Many fertilizer suppliers have waited for
nitrogen prices to come down before filling
tanks and warehouses. It would be a good
idea to ensure that you have adequate
nitrogen supplies for your crops early this
year.

DLW

Report of 2004 Agronomic Crop Production

The USDA's National Agricultural Statistics Service released the following estimates of crop
production in 2004:

Harvested Acres
(X1000) Yield per Acre

Crop Florida United States Florida United States

Corn for grain 32 73,632 90 bu 160.4 bu

Corn for silage 33 6,103 17 ton 17.6 ton

Cotton, all 87 13,057 524 lb 846 lb

Hay, all 260 61,916 2.5 ton 2.55 ton

Peanuts 130 1,394 2800 lb 3057 lb

Soybeans 17 73,958 34 bu 42.5 bu

Sugarcane for sugar and seed 420 952.1 33.9 ton 30.8 ton

Tobacco, flue-cured 4 233.4 2450 lb 2261 lb

Wheat, all 15 49,999 45 bu 43.2 bu

The national corn, rice, soybean, and cotton estimates indicate that production and yield records
were established. Corn production was 17 percent above the previous record established in
2003, while yields were 18.2 bushels higher than the 2003 record. Rice production was 15
percent above last year and new yield records have been set in each of the last five years.
Soybean production was 28 percent above 2003 and yields were 8.6 bushels greater. Cotton
production was 26 percent above 2003, and yields were 116 pounds greater.

EBW

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; C. G. Chambliss, Extension Agronomist; J.A. Ferrell, Extension Agronomist, G. E. MacDonald, Weed
Researcher, M. B. Adjei, Forage Agronomist, E. B. Whitty, Extension Agronomist, D. L. Wright, Extension Agronomist.

	Table of Contents
	Row spacing and plant populations...
	Cover crops for strip tillage
	Forage quality terms and defin...
	Grazing management of perennial...
	Hay producers - prepare for the...
	Peanut inoculants
	Tobacco contracts
	Report of 2004 agronomic crop...