Table of Contents
 Corn growth and development
 Grazing management during...


Agronomy notes
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00066352/00047
 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: June 2004
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.
Funding: Florida Historical Agriculture and Rural Life
 Record Information
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: aleph - 000956365
notis - AER9014
System ID: UF00066352:00047

Table of Contents
    Table of Contents
        Page 1
    Corn growth and development
        Page 2 (MULTIPLE)
    Grazing management during a drought
        Page 3 (MULTIPLE)
        Page 4
Full Text


June, 2004


Corn Growth and Development .....
Late Nitrogen Fertilization of Corn .

Timely Management on Cotton .....

Ally Herbicide Changed to Cimarron
Bermudagrass Hayfields ..........
Grazing Management During a Drougl
Poisonous Plants ...............
Producing High Quality Grass Hay ..
Summer Annuals for Hay?........

. . . . . . . . 2

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Interim Dean.

Corn Growth and Development

The cool, dry spring that we encountered this year
has resulted in corn being under stress and showing
many symptoms that may not normally occur. The
early season purpling was caused by phosphorus
deficiency which will normally disappear as the
weather warms up and roots grow and explore more
soil. Starter fertilizer usually contains 20-35 lbs/A of
N and the same rate of P or more depending upon soil
test and minor elements. The first sidedress
application of nitrogen should be applied near the
row before the plant becomes N deficient from starter
N. This normally occurs by the time corn reaches 12-
15 inches tall. Another sidedress application is
usually needed on sandy soils by the time corn
reaches 24-30 inches tall. Other applications can be
made through irrigation water. Likewise, potassium
should be split on sandy soils or K deficiencies
symptoms will be noted on leaves of the plant.
Magnesium deficiency usually occurs later than other
nutrients and is often seen on foliage during peak
uptake of N. These symptoms occur as yellow stripes
on leaves and will soon disappear as Mg uptake
catches up with N uptake if adequate levels of Mg are
present in the soil. Application of dolomitic
limestone several months prior to planting supplies
adequate Mg.


Late Nitrogen Fertilization of Corn

Nitrogen fertilization should be done on a timely
basis. This means that N applications should be
made as plant needs it throughout the vegetative
period. Late applications after silking and tasseling
are not advisable. Yields are usually not increased
but grain protein content may increase. Nitrogen
deficiency early in the season can result in significant
yield reduction.


weed problems that can damage the crop. Growth
regulators should be applied to cotton early before
rank growth begins which will normally be by the 8-
10th node. One of the most common mistakes is to let
cotton get too rank before beginning applications of
growth regulators.


Ally Herbicide Changed to Cimarron

For several years the herbicide Ally has been used to
control weeds in pastures. Ally was particularly
useful against Pensacola bahiagrass, plantains, red
sorrel, wild radish and others. However, the name
'Ally' has been replaced by 'Cimarron'. Cimarron
contains metsulfuron and is sold as a 60 DF
formulation just as Ally was traditionally marketed.
So why the name change? DuPont has significantly
changed the product label and chose to also change
the product name to bring added attention to these

The two most notable changes are listed below.
Application Rate: Ally was labeled at a single rate of
0.3 oz/A. Cimarron now possesses a rate range of 0.1
to 1.0 oz/A. This has allowed new weeds to be added
to the label that are controlled at these elevated rates.
Application Timing: Cimarron is currently labeled for
use during the establishment of certain grass species
at 0.1 oz/A. Although bermudagrass still carries the
60 day restriction after establishment, other species
do not. Cimarron is currently being sold at
approximately $24 per ounce.

Another product being marketed by DuPont is
Cimarron Max. This is a co-pack product that
contains metsulfuron (the active ingredient in
Cimarron) and 2,4-D + dicamba (similar formulation
to Weedmaster). Although little research has been
conducted with this product in the South, these
herbicides are complimentary and should effectively
control a wide range of weedy pests.

Timely Management on Cotton

June is a critical month to get the crop off to a good
start. Good weed control and early thrips control can
make other management decisions easier later on.
Cotton will normally be side dressed with nitrogen
about 40 days after planting and rapid growth starts
after this period. Scouting for insects at early square
formation starts during the same time as the nitrogen
application. Even though most growers use Bt and
Roundup Ready cotton, the crop should be observed
closely to detect any nutrient deficiency, insects, or

Bermudagrass Hayfields

Dry weather once again has delayed growth of
bermudagrass. The drought may be over with recent
thunder storms and hopefully the bermudgrass will
start growing and be ready for harvest in three to four

Bermudagrass hay producers should keep a careful
watch for armyworm infestation. Check your fields

regularly. Look for the small worms (caterpillers)
and be ready to harvest, -- or spray if the grass is not
large enough to harvest. Watching for cattle egret
activity in the field may be helpful, but the worms
could be quite large before the birds find them. Small
worms are easier to control than large worms. In the
recent past, large outbreaks of armyworms have
followed an extended spring drought. Whether or not
there is a cause and effect relationship is not known
by the author but it is a good idea to be vigilant in any


Grazing Management During a Drought

During a drought, be careful not to overgraze
pastures. Some leaf surface should be maintained on
all of the improved grasses at all times. When
Floralta Limpograss (hemartheria) and other upright
growing grasses are grazed short, cattle should be
moved to a new pasture where growth has
accumulated; or if grass is not available on any of
your pastures, move the animals onto bahiagrass
which has the ability to maintain some leaf by
growing it flat against the soil surface where cattle
are usually not able to remove it. Feed hay or other
supplements on bahiagrass when there is no longer
any grazing left anywhere on the ranch.


Poisonous Plants

Due to the April/May drought, many pastures are no
longer providing grazing. Animals are hungry and
may tend to eat plants that they would not normally
eat. In low wet areas around the edges and within
somewhat open woodlands, the plant "bracken fern"
can often be found growing. This plant is poisonous
to cattle. Producers should be especially careful if
they are moving cattle into new areas, such as into the
woods. These areas should be checked for bracken
fern and other poisonous plants. If bracken fern is
found, do not put animals into those areas or at least
observe the grazing habits of the cattle to see if they
are eating the fern. A couple of other poisonous
plants to watch for are lantana and wild chery.
When the summer rain pattern starts, afternoon
thundershowers with accompanying wind gusts may
blow down wild cherry trees that are growing in the
fence rows. Cattle will tend to eat the leaves which
are poisonous.


Producing High Quality Grass Hay

Crude protein and total digestible nutrients (TDN) are
two important measures of hay quality. Stage of
maturity or age of the plant at harvest is the most
important factor influencing hay quality. As plants
increase in age, crude protein and digestible energy
concentration decrease. The improved hybrid
bermudagrasses and stargrasses should be harvested
at 15 18 inches for the first cutting and then cut
every 4 to 5 weeks. During mid summer, some
producers are harvesting stargrass for silage every
three weeks to produce feed that has a protein
concentration of 15 percent or greater and a relatively
high TDN.

All hay equipment should be serviced and repaired
before the hay season begins. A breakdown during
harvest almost guarantees rain damage to the hay.
Rain leaches soluble nutrients from the grass. It
prevents the grass from drying quickly and thus,
increases respiration loss and the possibility of mold.
Respiration is the breakdown of sugars etc. in the
plant. This process occurs in all living plants, and it
continues after the plants are cut. Respiration stops
when the moisture content drops below 40 percent.
In Florida's climate, rain damage is difficult to avoid.
Frequent thunder showers in the summer will usually
hit one or more hay harvests. During the summer if a
suitable period of weather occurs for harvesting hay,
and if the grass is long enough (15 inches), it may be
wise to start harvesting even though the regrowth has
not reached a 4 or 5 week schedule.


Summer Annuals for Hay?

Producers occasionally ask about choices for a
summer hay crop that can be grown on cultivated
land. Various crops could be used such as pearl
millet or sorghum x sudangrass, japanese or brown
top millet, crabgrass, and perhaps rhodesgrass,
cowpeas, soybeans and alyceclover. Those
attempting to grow pearl millet or sorghum x
sudangrass for hay should be aware that their large
stems make drying difficult. A hay conditioner that
crushes or breaks the stems will be needed. Brown
Midrib (BMR) sorghum-sudangrass varieties are
available, and these have a higher level of
digestibility than the traditional varieties. High
quality hay can be made from adapted soybean
varieties, but producers should be aware of problems
associated with growing soybeans such as getting
good nodulation when planted on ground where
soybeans have never been grown before. Also,

insects and nematodes may be a problem.
Alyceclover may be the best choice. Following a
highly fertilized crop, such as watermelons or other
vegetables on well-drained soils, alyceclover
produces excellent quality forage that may be grazed
or harvested as hay. This summer annual legume
should be planted between April 15 and June 30 at
the rate of 12 to 15 pounds of seed per acre. Seed are
usually broadcast and covered with a cultipacker or
planted with a grain drill that has a small seed box
and covered to a depth of 1/4 to 1/2 inch. Fertilize and
lime according to soil test recommendations. If
alyceclover is planted immediately following a highly
fertilized crop, it may not be necessary to add lime or

fertilizer. Do not plant alyceclover on land known to
be infested with rootknot nematodes, since
alyceclover is susceptible to this pest. Do not plant
alyceclover (intended for hay harvest) on land
infested with coffeeweed. Coffeeweed is toxic to
livestock. Herbicides are not available that will
remove coffeeweed from alyceclover. If the
coffeeweed were to grow taller than the alyceclover
(which is not likely), it might be possible to remove it
with a weed wiper and Roundup.


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