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Research
and Outreach |
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Selected Areas
of Research in the UGA Cotton Physiology Program |
Progress
Reports 2004 |
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POSTER AND SLIDE PRESENTATIONS
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| The following
paragraphs elaborate on several areas of research in the University
of Georgia cotton physiology program.
Cotton
Irrigation Scheduling Cotton
Subsurface Drip Irrigation Cotton
Population Densities
Phenological
and Morphological Components of Cotton Crop Maturity Cotton
Compensation for Early Season Fruit Loss |
Increased irrigated row crop acreage in Georgia along with increased
population growth and water consumption in North Georgia and the
Florida Panhandle have diminished the regions water resources. Thus,
it is prudent to begin investigating means for more conservative
irrigation management in the Southeast. With the introduction of
variable rate irrigation systems, remote sensing offers a relatively
low-cost method to monitor large acreages and irrigate accordingly.
We are examining overhead imagery as a method for cotton irrigation
scheduling. Images are collected with visible and near-infrared
cameras suspended from a tethered blimp and remote sensing-based
irrigation is compared with a soil water content irrigation trigger.
To date, irrigation scheduling based on remote sensing has produced
yields comparable with scheduling based on soil water content monitoring
with less irrigation water applied. 
Subsurface
drip irrigation (SDI) has the potential to provide consistently
high yields under variable precipitation while conserving water.
Some researchers have shown cotton lint yield and fiber quality
may be improved with SDI. It is possible these improvements result
from more frequent irrigations with SDI, reducing the risk of episodic
drought stress. It is also possible improved yield and quality with
SDI may result from the avoidance of sprinkler-induced flower losses
and yield reductions. Regardless, differences in lint yield, fiber
quality and profitability between SDI and overhead sprinkler irrigation
have yet to be determined in the Southern Coastal Plain. 
One
addition that may strengthen cotton integrated pest management systems
and lessen the dependence on insecticides is the potential for compensatory
growth following early season floral bud loss due to insect pests.
Inclusion of plant compensation in economic injury levels would
raise treatment thresholds, thereby reducing insecticide applications
and the costs, contamination, and resistance development related
to them. We conducted controlled studies to quantify the ability
of cotton to compensate for early season floral bud loss. Modifications
in spatial yield distribution adequately replaced those floral buds
removed early in the season because total seed cotton yield was
not different among the treatments at crop maturity. If early-season
insecticide applications were eliminated, this could save approximately
$8.92 per acre per application for Georgia cotton producers. Also,
if one early-season insecticide application were eliminated on 20%
of Georgia cotton acreage (due to inclusion of plant compensation
in the IPM model), this would decrease insecticide use (and the
environmental exposure associated with it) by more than 86,000 pounds
in the state of Georgia annually.