In soil science, what does organic matter primarily contribute to?

Organic matter plays a crucial role in enhancing cation exchange capacity, which is the ability of soil to hold and exchange positively charged ions (cations) such as calcium, magnesium, and potassium. When organic matter decomposes, it forms humic substances that have a high affinity for cations due to their negatively charged sites. This characteristic not only improves the soil's fertility by increasing nutrient availability but also supports plant growth.

The presence of organic matter in the soil improves overall soil structure and promotes the formation of aggregates, which can indirectly influence water retention and aeration. However, its direct impact on cation exchange is more significant, making it essential for maintaining soil health and supporting crop production.

While other factors like soil texture may influence cation exchange capacity, organic matter uniquely enhances this property, providing a vital function that supports sustainable agricultural practices.