What is the main benefit of increasing organic matter in soil?

Increasing organic matter in soil primarily benefits soil structure. Organic matter improves the aggregation of soil particles, which enhances porosity and promotes better aeration and water infiltration. This creates a healthier environment for plant roots and microorganisms, facilitating nutrient exchange and overall soil fertility. A well-structured soil is essential for effective water retention, which benefits plants by ensuring they have access to moisture.

Improved soil structure can also contribute to various other benefits such as better root development and stability, which can lead to higher crop yields. The presence of organic matter helps to create a more resilient soil ecosystem that can better withstand erosion and compaction.

The other options do not align with the main advantages of increasing organic matter in soil. For instance, decreasing water retention would be counterproductive, and reducing plant diversity runs contrary to the goals of sustainable agriculture. Additionally, while improving organic matter can help manage soil pests, this is not its primary function compared to the significant impact on soil structure.