Which statement best describes the benefit of growing clover in a crop rotation?

Which statement best describes the benefit of growing clover in a crop rotation?

• A. It blocks sunlight to subsequent crops.
• B. It fixes atmospheric nitrogen through root nodules, improving soil fertility.
• C. It lowers soil pH drastically.
• D. It cannot survive in most soils.

Answer: (B)

The key idea is that clover, as a legume, can boost soil nitrogen through a natural partnership with nitrogen-fixing bacteria in its roots. These bacteria form nodules on clover roots and convert atmospheric nitrogen (N2) into ammonia and related compounds that the plant can use. This process increases the available nitrogen in the soil, which helps subsequent crops in the rotation grow better and can reduce the need for synthetic nitrogen fertilizer. In crop rotations, this nitrogen contribution from clover is a major reason to include legumes. Other statements don’t describe the main advantage. Clover isn’t grown to block sunlight as a primary benefit, it doesn’t drastically lower soil pH, and it isn’t true that it can’t survive in most soils.

The key idea is that clover, as a legume, can boost soil nitrogen through a natural partnership with nitrogen-fixing bacteria in its roots. These bacteria form nodules on clover roots and convert atmospheric nitrogen (N2) into ammonia and related compounds that the plant can use. This process increases the available nitrogen in the soil, which helps subsequent crops in the rotation grow better and can reduce the need for synthetic nitrogen fertilizer. In crop rotations, this nitrogen contribution from clover is a major reason to include legumes.

Other statements don’t describe the main advantage. Clover isn’t grown to block sunlight as a primary benefit, it doesn’t drastically lower soil pH, and it isn’t true that it can’t survive in most soils.