Which practice can enhance nitrogen mineralization in agricultural soils?

Increasing organic matter content in agricultural soils is a well-established practice that can significantly enhance nitrogen mineralization. Organic matter, which includes decomposed plant and animal residues, serves as a reservoir for nutrients. As it decomposes, microorganisms break down the organic matter, which releases nitrogen in a form that plants can readily absorb, such as ammonium and nitrate. Higher levels of organic matter also improve soil structure, water retention, and microbial activity, all of which facilitate the mineralization process.

The addition of organic materials, such as compost, cover crops, or manure, enriches the soil with not just nitrogen, but also a broader spectrum of essential nutrients and improves overall soil health. This results in a more sustainable and productive agricultural system.

In contrast, other options may not effectively promote nitrogen mineralization or may even impede it. For instance, frequent tilling and excessive soil disturbance can disrupt soil microorganisms and their activities necessary for nutrient cycling. Reducing crop rotation diversity can lead to depletion of soil nutrients and lessen microbial diversity, which diminishes the overall soil health and its ability to mineralize nitrogen. Applying lime primarily helps manage soil acidity and can indirectly affect nutrient availability, but it does not directly enhance nitrogen mineralization like increased organic matter does.