http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Benefits and Consequences of No-Tillage and Cover Crops in Semi-Arid Cotton Production
The Texas High Plains (THP) is one of the most agriculturally productive regions of the world, however, the climatic conditions of the area can result in significant wind erosion exemplified by the Dust Bowl of the 1930s. Conservation management practices, such as no-tillage and cover cropping during traditional fallow periods have the potential to significantly reduce wind erodibility, but adoption has been slow because of producers' concerns regarding yield reductions following these practices. The purpose of my studies was to evaluate the two most common concerns with conservation adoption (water limitations and nitrogen (N) immobilization) and quantify the secondary ecosystem service (soil health) benefits from their adoption. The experiments were conducted at the Agricultural Complex for Advanced Research and Extension Systems in Lamesa, TX, in a long-term continuous cotton (Gossypium hirsutum L.) cropping system established in 1998. Treatments included 1) conventional tillage, winter fallow (CT); 2) no-tillage with rye (R-NT) (Secale cereal L.) cover crop; and 3) no-tillage with mixed species cover (M-NT). The mixed species cover consisted of 50% rye, 33% Austrian winter pea (Pisum sativum L.), 10% hairy vetch (Vicia villosa Roth), and 7% radish (Raphanus sativus L.), by seed weight. Results indicate that R-NT and M-NT significantly increased in-season water and did not reduce cotton yields compared to CT, which challenges the most commonly referenced reason for yield reduction on the THP. Herbage mass decomposition rates in the N immobilization study indicated that cover crop biomass production can potentially negatively impact N cycling potential, while supplemental N earlier in the season can increase cotton lint yield compared to existing Extension fertilizer application recommendations. Conservation management practices significantly increased biological indicators of soil health relative to CT and, in some instances, to native rangeland. Combined, these results demonstrate the additive benefits of conservation practices on the semi-arid THP. Further work addressing the economic and social dynamics of these conservation practices is still needed before widespread adoption should be expected. The electronic version of this dissertation is accessible from https://hdl.handle.net/1969.1/198469
Doctor of Philosophy Texas A&M University 2022 https://hdl.handle.net/1969.1/198469