What role does organic matter play in soil structure?

Organic matter plays a crucial role in enhancing soil aggregation, which is the process where soil particles bind together to form larger clusters known as aggregates. These aggregates improve soil structure by increasing porosity and improving water infiltration and retention.

When organic matter decomposes, it releases compounds that help bind soil particles together, creating a more stable structure. This stable soil structure allows for better root growth, increases the soil's capacity to retain moisture, and enhances the overall health of the soil ecosystem by promoting beneficial microbial activity.

In contrast, the other options do not align with the primary functions of organic matter in soil. While organic matter can help in reducing soil compaction and can have a positive effect on air circulation, these aspects are secondary to its role in promoting aggregation. Organic matter does not limit air circulation; rather, well-aggregated soil typically has improved aeration. Additionally, organic matter enhances nutrient availability rather than reducing it, as it serves as a reservoir for essential nutrients needed by plants.