Cover Crop and No-Tillage Effects on Soil Health Indicators and Arbuscular Mycorrhizal Fungi Diversity in Indiana.

The concept of soil health has grown in popularity across the Midwest U.S.A. due to rising concerns of meeting the food demands of an increasing world population while maintaining or improving environmental quality. In 2012, 17 sites were established across Indiana to quantify the impact of cover crops and no-tillage on soil health. Three sites are owned by Purdue University, two by other public entities, and the remaining 12 by farmer cooperators. Six conventional comparison sites were added in 2016. At the Purdue sites, three to four blocks of a no-till corn (Zea mays L.)/soybean (Glycine max (L.) Merr.) rotation were established. Treatments before corn include a no cover crop control, a mixture of oats (Avena sativa L.) and oilseed radish (Raphanus sativus L.), and a mixture of oats, oilseed radish, crimson clover (Trifolium incarnatum L.), and cereal rye (Secale cereal L.). Treatments before soybean include a no cover control, cereal rye, and a mixture of oats, oilseed radish, and cereal rye. At the farmer sites the specific cover crop species vary among sites, but there are usually three blocks including a no cover control with either reduced or no-till and a cover treatment with no-till. Several soil parameters have been measured throughout this study. Added in 2016, arbuscular mycorrhizal fungi diversity among plots with cover and no-till, no cover and no-till, and no cover and conventional till is being quantified by root staining, spore extraction, and DNA analysis. Preliminary results indicate a high population variability of spores within and across samples, perhaps due to the unknown amount of time the spores were within the soil matrix before field sampling. Mycorrhizae can advantageously influence plant nutrient uptake; understanding how they are impacted by cover crops and no-tillage could help improve overall soil health.