Soil Benefits and Yield Limitations of Cover Crop Use in Texas High Plains Cotton

Abstract

Core Ideas Soil organic C was two times greater with a no‐tillage rye cover crop system compared with conventional tillage (winter fallow) 17 yr after imposing treatments. A greater rate of C gain was observed with a no‐tillage mixed species cover crop system than with a rye cover crop in a 3‐yr period. Cotton lint yield and gross margins were less with a no‐tillage rye cover crop system than conventional tillage. Differences of lint yield and gross margins did not exist between the conventional tillage and no‐tillage mixed species cover crop treatments. Conservation tillage coupled with winter cover crops may reduce wind erosion in the North America Great Plains. Although farmers recognize the benefits of conservation practices, their decision to use cover crops is often based on the farm’s operating budget. In semiarid ecoregions dependent on irrigation for cotton (Gossypium hirsutum L.) production and limited groundwater resources, cover crops using stored soil moisture is a major concern. The objective of this research was to quantify the long‐term impacts of conservation tillage and cover crop use on C storage, cotton lint yield, and economic returns in monoculture cotton production. Conservation tillage and rye cover were implemented in 1998 and a mixed species cover of rye (Secale cereale L.), hairy vetch (Vicia villosa Roth), radish (Raphanus sativus L.), and winter pea (Pisum sativum L.) was seeded in 2014 into half of the rye cover crop plots. Soil organic C in the top 15‐cm soil depth was increased by combining conservation tillage with winter cover crops. Cotton lint yield was less with no‐tillage and the rye cover when compared with conventional tillage in 2 of 3 yr. As a result, cotton lint revenue and gross margins of conservation tillage were on average less than conventional tillage.