Farm406

49 farm406 Cover crops are one tool to improve soil health and long- term agricultural sustainability, especially when grown in place of summer fallow, according to Clain Jones, co-author of the publications and Extension soil fertility specialist in the MSU Department of Land Resources and Environmental Sciences. e publications explain the benefits and cautions of using cover crops, also called covers, as partial replacement of fallow in semi-arid dryland cropping systems. "Covers can increase plant diversity, keep the soil covered, and increase the time active roots are in the soil, especially compared to fallow," Jones said. "ese benefits are all important to regenerate and maintain soil health." "e main drawback of using covers in semi-arid dryland cropping systems is their use of stored soil water, which can reduce cash crop yields the following year," Jones said. "Cover Crops: Soil Water and Small Grain Yield and Protein" presents the results from years of regional research. Perry Miller, co-author and cropping systems professor in the Department of Land Resources and Environmental Sciences, has found early termination of covers is the key to minimizing subsequent cash crop loss due to cover crop water use. "Cash crop losses are least when legume covers – such as pea or lentil – are terminated by first bloom, and grasses are terminated around the time heads emerge from the sheath," said Miller. Covers are oen grown to increase soil health, Miller added, and soil organic maer contributes to soil health and is directly related to plant residue. "However, in dryland systems, the biomass or plant residue gained by leing covers grow past first bloom does not always offset the lower amount of residue produced by lower cash crop growth," Miller said. "Covers need to be considered in the whole system, overall rotations on a field, to determine their net impact on plant residue on a given field, including potential to add nitrogen to the soil for the next crop," Miller adds. "In our dry systems, it is always a balance between covers contributing plant residue and nitrogen against the amount of water they use, which decreases cash crop yield," Miller said. Small grain protein is usually higher following legume covers. However, nitrogen from legume residue is oen not available early enough in the growing season to benefit small grain yields, at least until legume covers (or pulse crops) have been in rotation three to four times. Jones said it's important to soil test for nitrate in the spring following legumes and adjust nitrogen fertilizer rates according to soil test levels. "Cover Crops: Management for Organic Maer and Nitrogen" focuses on cover management to benefit soil nitrogen and organic maer. e authors say building soil organic maer is a slow process, but small gains in soil organic maer can lead to improvements in soil health and structure, which are essential to the long-term viability of farmland. When legumes represent most of a cover mix, the accumulation of nitrogen over time in the soil allows for reduced nitrogen fertilizer rates. store.msuextension.org

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