Soil microorganisms cause what effect on soil structure when crop residues are added?

When crop residues are added to the soil, soil microorganisms play a vital role in enhancing soil structure. As microorganisms decompose the organic materials in the residues, they produce substances like polysaccharides, which act as glue, binding soil particles together. This process leads to the formation of aggregates, which are clusters of soil particles. The increase in aggregates improves soil porosity, aeration, and water infiltration, ultimately leading to better root development and nutrient uptake for crops.

The microbial activity not only contributes to the physical improvement of soil structure but also encourages a diverse ecosystem of microorganisms that further aids in nutrient cycling and enhances soil health over time. Consequently, the addition of crop residues positively influences the soil structure, leading to an increase rather than a decrease or no change.