• Gene D. Wills (PI) - Plant Physiologist, Mississippi State University
• James E. Hanks (Co-PI)

Remote sensing technology is being conducted on plots of approximately one-half acre each consisting of cotton spaced 38 inches apart and 800 feet long. Each plot is georeferenced every 200 feet beginning 100 feet inside the end of the plot with more frequent reference points where previous evaluations have shown rapid changes in growth of cotton from one location to another.

Several parameters are being measured at each georeferenced location. At the beginning of the study, soil parameters including nutrient levels of N, P, K, Ca, Mg, Na Zn, B, and Mn, percent organic matter, cation exchange capacity, and texture were determined. Periodic evaluations throughout the growing season include evaluation of vegetative cover (vegetative index) beginning with bare ground before planting and continuing until harvest. Validations include periodic measurements of plant height, length of internodes and width of canopy across rows. Leaf tissue analyses determine the levels of N, P, K, Ca, Mg, Na, Zn, B, and Mn beginning at the time of first flower. Further analyses include the percent of boll opening and the percent of cotton defoliation.

Individual treatments will be 1) untreated control, 2) conventional constant rates of growth regulator and defoliant, 3) variable rate application of a growth regulator as prescribed according to ground-truth data plus a conventional constant rate of defoliant, 4) conventional constant application rate of growth regulator plus variable rate applications of a defoliant as prescribed according to ground-truth data, 5) variable rate applications of both growth regulator and defoliant as prescribed according to ground-truth data, and 6) conventional constant rate of defoliant (no growth regulator). Each treatment is replicated three times in a randomized complete block design.

Correlations will be made between soil characteristics, vegetative growth, and the results of the chemical applications.

Global Positioning System (GPS) controlled spray equipment is available for conventional and variable rate applications. Plots will be harvested with a cotton picker which is equipped with a GPS controlled yield monitor. Cotton from each plot will be weighed for verification. GIS software will be used to process and map all data.