Used to prepare the soil before planting or between two crops, green manures replace perennials or annuals that nature would otherwise grow to cover the soil. They aerate the soil thanks to their root system and draw mineral elements from deep within the soil, which they release as they decompose. Their covering effect also limits soil erosion and leaching. When mowed, they make excellent mulch and add organic matter directly to the soil. Green manures from the Fabaceae family have the ability to capture nitrogen from the air, making it more readily available in the soil for subsequent crops.