Why would farmers plow the crop of legumes into ground instead harvesting it?

Legumes, such as soybeans, peanuts, and clover, are often plowed into the ground as a process known as "green manuring" instead of being harvested for several reasons:

1. Soil Fertility Improvement: Legumes have the ability to fix atmospheric nitrogen through a symbiotic relationship with bacteria in their root nodules. When these plants are plowed into the soil, the nitrogen-rich biomass decomposes and releases nitrogen into the soil. This natural process enriches the soil, enhancing its fertility and reducing the need for synthetic nitrogen fertilizers.

2. Organic Matter Addition: Legumes produce a significant amount of organic matter, which consists of plant residues and decaying roots. When plowed into the soil, this organic matter improves soil structure, aeration, and water-holding capacity. It also provides a source of nutrients for beneficial soil microorganisms, fostering a healthy soil ecosystem.

3. Weed Suppression: Legumes can help suppress weed growth in subsequent crops. Their dense growth and ability to release allelopathic substances can inhibit the germination and growth of certain weed species. Plowing legumes into the ground continues this weed-suppressing effect.

4. Erosion Control: The dense root systems of legumes help hold the soil in place, reducing soil erosion caused by wind and water. By leaving crop residue on the soil surface or incorporating it through plowing, farmers can protect against soil loss and preserve the soil's structure and fertility.

5. Disease and Pest Management: Plowing under legume crops can help manage certain soilborne diseases and pests. By breaking the disease cycle and disrupting pest habitats, farmers can reduce the risk of infestations in future crops.

6. Nutrient Recycling: Legumes have the ability to absorb nutrients, such as phosphorus, potassium, and calcium, from the soil and store them in their tissues. When plowed into the ground, these nutrients are released back into the soil, making them available for other plants.

In summary, farmers may choose to plow legume crops into the soil rather than harvest them to improve soil fertility, add organic matter, suppress weeds, control erosion, manage pests and diseases, and recycle nutrients. This practice is a sustainable and eco-friendly way to maintain soil health and enhance agricultural productivity.