What are green manures and cover crops, and what roles do they play in nutrient cycling and soil protection?

• A. Green manures are crops grown to be incorporated to improve soil fertility.
• B. Cover crops protect soil from erosion and improve soil structure.
• C. Green manures are crops grown to be incorporated to improve soil fertility; cover crops protect soil from erosion and improve soil structure; both contribute organic matter and nutrient cycling.
• D. Green manures are trees; cover crops are annual vegetables.

Answer: (C)

Green manures and cover crops are practices that involve growing crops specifically to benefit soil health. A green manure is grown with the intention of being incorporated into the soil to boost fertility. When these plants are dug in or decompose, they add organic matter, feed soil microbes, and improve soil structure; legumes also fix atmospheric nitrogen, increasing available nitrogen for future crops. Cover crops are grown to keep the soil-covered, protecting it from erosion and compaction, while their roots enhance soil structure and porosity and their biomass contributes to organic matter. Both practices support nutrient cycling by capturing nutrients when the crops are grown and returning them to the soil as residues decompose, helping retain nutrients and release them gradually for subsequent crops. Together, they enrich soil organic matter and sustain nutrient cycling, while also protecting soil from erosion and improving soil physical properties.