What is the primary factor that affects the sorption capacity of soils?

The primary factor that affects the sorption capacity of soils is soil texture. Soil texture refers to the relative proportion of sand, silt, and clay particles within the soil. This composition significantly influences how well the soil can retain and absorb water and nutrients.

Soils with a higher clay content typically have greater sorption capacity because clay particles have a large surface area and are able to hold more water and nutrients compared to sand or silt. The smaller particle size and greater surface area of clay provide more sites for chemical interactions, enhancing the soil's ability to retain important elements for plant growth. Additionally, the texture affects the soil's permeability and aeration, which also play roles in nutrient and water retention.

While factors such as moisture, structure, and temperature can influence the overall performance of soils regarding nutrient retention and availability, they are secondary to the intrinsic capabilities determined by the soil's texture. Therefore, understanding soil texture is crucial for managing fertility and enhancing crop production effectively.