What is the role of soil microorganisms in nutrient cycling?

Soil microorganisms play a crucial role in nutrient cycling primarily by decomposing organic matter and converting nutrients into forms that are accessible to plants. This process begins when microorganisms break down complex organic materials, such as dead plants and animals, releasing nutrients like nitrogen, phosphorus, and sulfur in forms that plants can readily absorb.

Through their activities, these microorganisms help mineralize nutrients, transforming them from organic forms into inorganic forms, which are essential for plant growth. This decomposition process not only recycles nutrients back into the ecosystem but also contributes to soil fertility and productivity. The presence of a diverse array of microorganisms can enhance the efficiency of nutrient cycling, supporting healthy plant growth and the overall health of the soil ecosystem.

The other options do touch on aspects of soil health and ecology but do not correctly reflect the primary role of microorganisms in nutrient cycling. While some microorganisms might produce substances that can affect pests, and they can influence soil structure and aeration, their fundamental contribution to nutrient cycling is through the decomposition and nutrient conversion processes. Similarly, while competition for nutrients among organisms happens, it is not the defining role of soil microorganisms in the context of nutrient cycling.