Nitrogen Availability and Corn Production in Minnesota Following Cover Crops.

Cover crops are often included in BMPs for reducing soil erosion, building soil organic matter, and reducing nitrate leaching. However, because of additional management requirements and uncertainties about their impact on nitrogen availability and cash crop yields, cover crops have not been widely adopted in conventional fields. This study aims to reduce these uncertainties for corn growers in Minnesota. In 2015, winter annual cover crops were established following soybeans at three Minnesota locations. In spring 2016, cover crops were terminated, corn was planted, and 6 nitrogen rates were applied. Corn yield was measured and plateau nitrogen rates determined for each cover crop treatment. Additionally, plant available nitrogen was tracked through the growing season using two methods: KCl extractable nitrogen in 30 cm cores; and plant available nitrogen supplied over time on Plant Root Simulator resin probes.