Cover crops like cereal rye and hairy vetch can help reduce nitrogen loss from Midwest farms. A study looked at how these cover crops affect nitrogen levels and grain production in corn and soybean fields. They found that cover crop residue releases nutrients that can compete with cash crops for soil nitrogen. Cereal rye nitrogen isn't used much by the next crop, so it's better for long-term soil health. Early soybean growth can be affected by too much cereal rye, leading to lower yields in wet years.