Untitled Document

Current Research
Briefs

On-farm Testing of Precision Agriculture Technologies for Texas High Plains Cotton
   


Principal Investigator: Kevin F. Bronson
Texas Agricultural Experiment Station, Lubbock

Cooperators:
College Station - S. Searcy
Lubbock - J.W. Keeling, T. Wheeler, A. Brashears,
R.J. Lascano, C. Trostle, T. Chua, R. Boman,
P. Dotray, and E. Segarra

 

 The blanket treatment rate of P fertilization was based on an average of 20 soil samples taken from the blanket-rate plot areas. Variable-rate P fertilizations were made with a liquid fertilizer rig fitted with variable-rate controllers and software (Agchem/SOILTEQ, Minnetonka, MN) equipment, and was GPS referenced and ground speed radar controlled. Variable-rate or on/off post-direct Roundup® applications were made with an infrared Weed Seeker shielded sprayer (Patchen® Selective Spray System, Los Gatos, CA). Variable-rate Temik® applications, based on soil samples and remote sensing, were made by manually adjusting nematicide hoppers on the planter.
Primary Research Locations: Ropesville and Lamesa, TX
  		Some preliminary observations ...
This project was designed to evaluate the precision agriculture (PA) practices in cotton at two sites of grid soil sampling/analysis, and variable-rate technologies (VRT) compared to conventional, blanket applications of fertilizer, herbicide and nematicide.

·Temik® applications did not affect lint yields. Although weed control was not different, input costs of variable Roundup® herbicide applications were just $2 an acre compared to $9 an acre for the blanket-rate spraying.

·Lint yields with variable-rate P fertilizer, were significantly greater than zero P plots at both sites. The blanket-rate of P fertilizer, however, did not affect lint yields, relative to the zero-P control.
Precision agriculture technologies such as variable-rate fertilization and light-activated Weed Seeker shielded sprayer are now commercially available. However, little systematic and scientific testing of these technologies have been done with cotton
in the Texas High Plains.

Producers are interested in PA, but are not sure what the agronomic or economic benefits of shifting from conventional, whole-field, blanket-rate farming to VRT would be.

 Preliminary economic cost and returns of inputs showed —

PA practices resulted in greater variable returns than blanket-rate management. However, this analysis did not consider capital costs of variable-rate application equipment or the greater cost of 0.5-ac grid soil sampling and laboratory analysis for the VRT treatments.
For the 2000 growing season ...
we tested variable-rate P fertilization and nematicide applications at two sites, Ropesville and Lamesa.
· Variable-rate Roundup® herbicide post-direct applications were only done at Ropesville due to low weed pressure at Lamesa.
· Phosphorus fertilization was based Mehlich-3-extractable P from 0-6 in. soil samples.
· Sixty of these soil samples were taken on a 0.5-ac grid, which were global positioning system (GPS) referenced, at each of the 30-ac sites. Plots were 16, 40-in. rows wide and about half of a center pivot long. 		. What's ahead in 2001 — We plan to repeat this study at these two sites in the upcoming growing season.