What process can increase nitrogen availability in the soil?

Crop rotation is a crucial agricultural practice that can significantly increase nitrogen availability in the soil. This process involves alternating the types of crops grown in a particular area from one season to the next. Leguminous plants, such as peas and beans, are particularly effective because they have the ability to fix atmospheric nitrogen through a symbiotic relationship with specific soil bacteria. When these crops are rotated with non-leguminous crops, the nitrogen fixed by the legumes becomes available to subsequent crops, enhancing their growth and yield.

Additionally, crop rotation helps to improve soil structure, reduce soil erosion, and interrupt pest and disease cycles, all of which contribute to a more sustainable agricultural system. This process, therefore, not only increases nitrogen availability but also promotes overall soil health.

In contrast, practices like contouring and soil compaction do not directly relate to increasing nitrogen levels in the soil. Contouring focuses on the physical layout of land to reduce erosion and manage water flow, while soil compaction generally leads to reduced pore space and oxygen availability, which can hinder root growth and nutrient uptake. Without the benefits associated with crop rotation, nitrogen availability may not be adequately enhanced.