Soil Microbial Diversity and Nutrient Cycling in Dual Purpose Wheat Systems.

Dual purpose continuous wheat system for grain and grazing common in the Southern Great Plains has detrimental effects on soil quality and nutrient status. Conservation practices coupled with cover crops can improve soil health and sustain dual purpose systems. 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 dual-purpose practices on soil microbial diversity and nutrient cycling in Texas Rolling Plains. The study was randomized complete block design with seven treatments replicated four times. The treatments were conventional till wheat without a cover crop; no-till wheat without a cover crop; no-till wheat with a terminated summer cover crop; no-till wheat with a grazed summer cover crop; no-till wheat intercropped with turnip/radish without summer cover crop; no-till wheat intercropped with turnip/radish with terminated summer cover crop; and no-till wheat intercropped with turnip/radish with grazed summer cover crop. Phospholipid Fatty Acid (PFLA) 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. Preliminary results are showing no-till wheat with a grazed summer cover crop treatment with highest total bacteria, actinomycetes, fungi, arbscular mycorrhizal and protozoa biomass with conventional till wheat without a cover crop treatment showing the least. Diversity index is good in all no till and cover crops treatments but conventional till. Conservation practices manifesting healthier ecosystem. Related nutrient cycling data is in process.