Microbial Diversity and Nutrient Cycling in Wheat Systems with and without Cover Crops.

Winter wheat is a valuable and one of the most important cash crops grown in Texas, often utilized for both grain and forage. Continuous production is a common practice in the southern Great Plains. This tends to have negative effects on the ecosystem services and function of the soil. Cover crops have shown increased nutrient use efficiency and soil microbial diversity. However precise data on microbial diversity and nutrient cycling is lacking. This study seeks to evaluate and quantify the impact of cover crops and no till in monoculture practices on soil microbial diversity and nutrient cycling in Texas Rolling Plains. The study was a randomized complete block design with seven treatments replicated four times. Treatments were conventional tillage and combinations of No Till, Cover crops, Grazing and Intercropping with radishes and turnips.  Phospholipid Fatty Acid (PLFA) soil microbial community analysis method was used. Soil samples where pulled 0-7.5 cm deep next to the plants and near the rooting structures. Total living microbial mass was higher for NT and cover treatments compared to CT. Microbial activity and organic carbon was higher in NT cover treatments than CT. No difference between NT cover and NT No cover. Haney soil tests showed significant differences in nitrate-N between cover crops and no-cover crops treatments in the first year and no significant differences in the two subsequent years. Haney tests showed no differences among treatments for P and higher K in some cover compared to conventional till in the third year. Conventional till had the least organic N, C, NH₄-N and least CO₂ –C released compared to No-till, cover, grazed and intercropped treatments. No significant effects due to intercropping and grazing.