Kipling S. Balkcom1, Francisco J. Arriaga1, Jason S. Bergtold1, Charles Mitchell2, and Dennis P. Delaney3. (1) USDA-ARS, NSDL 411 S. Donahue Drive, Auburn, AL 36832, (2) Auburn University, 202 Funchess Hall, Auburn, AL 36849, (3) ACES, 106 Extension Hall, Auburn, AL 36849
The expected benefits associated with any type of conservation system requires the use of a winter annual cover crop in the Southeast, usually a winter cereal. A winter cover crop can be used to supplement previous crop residues to maximize the amount of residue left on the soil surface, which protects the soil from erosion during the winter and early spring months. Rye is a popular choice for growers with multiple years of experience with conservation systems due to its wide adaptability to soil fertility levels, climate zones, and biomass production. However, in order to maximize the benefits of a conservation system, supplemental N should be applied to enhance biomass production. An alternative to commercial N applied to the cover crop is poultry litter. Poultry litter is available to many growers and can be obtained at a lower price than commercial N. The organic N fraction of poultry litter is not readily available, but will supply N over a longer time-frame as the litter is decomposed by soil microorganisms. As a result, more residual N may be available to the subsequent cotton crop, thereby potentially reducing N requirements. No information exists on the optimal rates or time of application to maximize cover crop biomass production and how the potential residual effect of poultry litter affects cotton N requirements in a high residue conservation tillage system.
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