ABSTRACT

Cotton (Gossypium hirsutum L.) regrowth control with herbicides provides an alternative method for post-harvest destruction of cotton stalks. Field experiments were conducted in 2002 and 2003 to assess the effectiveness of different herbicide treatments for cotton regrowth control using remote sensing technology. Eight treatments (combinations of herbicides and application timings) and six treatments were evaluated in 2002 and 2003, respectively, with each experiment arranged in a randomized complete block design. Airborne multispectral imagery was acquired from the test plots in both years shortly before the state-mandated date for cotton stalk destruction. Ground reflectance spectra and plant visual ratings were also obtained from each experimental plot simultaneously. The reflectance spectra were able to detect differences in regrowth among some of the treatments. The airborne imagery permitted visual differentiation among some of the treatments. For quantitative analysis, the green, red, and near-infrared bands of the multispectral imagery and four vegetation indices derived from the three bands were used as spectral variables to compare the differences among the treatments for each experiment. Statistical analysis showed that the seven spectral variables were able to identify the differences among the treatments as detected by the ground observations. Results also indicated that the herbicide, 2,4-D (Savage), applied to shredded stalks at 1.12 kg formulation per hectare (1 lb/ac) twice within a one-month period provided excellent regrowth control.