Soil Health Benefits of Intensifying Winter Wheat Systems.

Wheat (Triticum aestivum), a staple cereal crop for human consumption and animal forage, is the third most produced field crop in the U.S., with Texas ranking the fifth largest producer. Conservation agriculture practices such as no-tillage and cover crops (CC) can potentially sustain traditional winter wheat monocropping systems in the Texas Rolling Plains by reducing degradation of soils by erosion during fallow periods; however, adoption of these practices is low throughout the region due to concerns of soil moisture use. The objective of this study was to evaluate two cropping practices, cover cropping and double cropping, under no-till management and their effects on soil health and crop yield in a dryland winter wheat production system. Eight treatments were compared including cowpea and mungbean as a cover crop (CC; 55-70 Days After Planting, DAP) or a double crop (DC; 70-90 DAP), and the termination timing of mixed species cover crops against a continuous wheat-fallow control. Mixtures were grown as a cover crop that was terminated early, late, or harvested as a hay crop. Soils were evaluated for microbial biomass using phospholipid fatty acid analysis (PLFA), permanganate oxidizable carbon (POXC), and carbon mineralization. Additionally, aggregate distribution (MWDA) and volumetric water content (VWC) were analyzed along with winter wheat yields. After three years of cover crops, it was found that treatments with cover and double crops trended higher in microbial biomass and carbon mineralization compared to wheat-fallow. There were no statistical differences at sampling times for POXC or MWDA. In 2017, wheat yields for cowpea and mix terminated treatments were significantly greater than wheat-fallow by 30-47% while in 2018, mixtures trended higher than wheat-fallow. Cover and double crops can be a means to increase soil health while not impacting soil moisture and subsequent wheat yields in a semi-arid no-till system.