Cotton Production Following Winter Biomass Crops in the Southeast.

A substantial amount of research is being conducted on producing energy from animal waste using thermochemical technologies. Winter cover crops are potentially an additional source of biomass to blend with the waste when making energy products. Removal of the biomass from fields could impact conservation tillage production of summer crops. This research was conducted to compare winter biomass crop species on subsequent cotton (Gossypium hirsutum) production with conservation tillage. Treatments in the study were three winter legumes (crimson clover (Trifolium incarnatum), Austrian winter pea (Pisum sativum), and vetch (Vicia villosa)] and three winter cereals [rye (Secale cereale), wheat (Triticum aestivum), and oat (Avena sativa)] near Florence, SC and near Auburn, AL in 2009 and 2010. The cover crops were no-till planted in October and harvested in early May at both locations. Following harvest of the aboveground biomass of the winter crops, cotton was seeded with in-row subsoiling. All fertilizer N (80 kg ha^-1) was applied at one month after emergence. Just before applying N, cotton growth and N uptake were measured. Cotton yields were determined following mechanical harvest and ginning of seedcotton. The winter cereals had higher biomass than the legumes, with rye providing the highest biomass of the cereals and vetch providing highest biomass of the legumes. Since no fertilizer N was applied at cotton planting, cotton following the legumes was larger than cotton following the cereals at one month after emergence. The early season growth advantage following the legumes did not result in higher yield at the end of the season. Lint yield did not differ among the winter biomass crop treatments under the good growing conditions at Florence (1200 kg lint ha^-1) or the stressed conditions at Auburn (460 kg lint ha^-1).