Improving Cotton (Gossypium hirsutum L.) Production through Non-Traditional Agricultural Practices

Cotton producers in the southeastern United States are highly competitive with foreign producers, despite being subjected to higher labor, shipping, and regulatory costs. Regardless, in order to remain competitive, fluctuation in market prices and input costs force producers to continually search for innovative methods to produce higher yield without incurring additional costs. In these studies, several aspects of cotton production were identified and researched to evaluate their potential cost savings and yield improvement. Experiments were designed to: increase land use and net returns through intercropping cotton (Gossypium hirsutum L.) and wheat (Triticum aestivum L.); reduce nitrogen costs by using winter legume cover crops; improve water conservation through furrow diking; and improve sensor-based variable nitrogen prescription rates by determining the effects of mepiquat chloride on normalized difference vegetative index values. Also, relay intercropping of cotton in wheat was researched as an alternative to traditional double-cropping in North Carolina.;The intercropping system produced wheat yield ranging from 65% to 85% of conventional wheat plantings, while maintaining cotton yield equal to mono-culture cotton. In addition, the intercropping system demonstrated the ability to suppress the population of thrips (Thysanoptera:Thripidae), with an economic return equaling that of conventional cotton planting and even exceeding that of double-cropped soybean. Furthermore, the use of legumes as a winter cover crop and a green manure was researched to determine the ease of establishment in un-harvested cotton in the fall and the ability to supply the total seasonal nitrogen requirement of cotton. Austrian winter pea (Pisum sativum L.) and crimson clover (Trifolium incarnatum L.) proved to be insensitive to the cotton harvest aid of thidiazuruon plus diuron in-field and provided the highest level of biomass when overseeded 14 days before defoliation. The highest lint yield was found when cover crops were terminated by a single broadcast herbicide applied 10 days before planting cotton. Lint yield of cotton treated with cover crops of crimson clover and hairy vetch (Vicia villosa Roth) equaled lint yield of cotton without cover crops and with 84 kg N ha-1 of liquid UAN applied. Net return of the legume cover crop/cotton system equaled net return of the cotton liquid nitrogen system.;Experiments were also conducted to determine the yield responses of corn (Zea mays L.), cotton (Gossypium hirsutum L.), and peanut (Arachis hypogaea L.) to furrow diking in conventional tillage systems. Results showed that corn and peanut yields were not affected by furrow diking; however, cotton yield increased by 7% during two of four years. Further experiments were conducted in Georgia and North Carolina to determine the effects of mepiquat chloride on the GreenSeeker RTM optical sensor values, also known as normalized difference vegetative index (red and near-infrared wavebands). Normalized difference vegetative index values obtained using the GreenSeekerRTM sensor were sensitive to nitrogen rates but insensitive to mepiquat chloride applications. Thus, the GreenSeekerRTM has the potential to assess plant nitrogen status and predict cotton nitrogen requirements, regardless of whether or not a mepiquat chloride application has been performed.