Certified Crop Advisor Practice Exam

Soil micros cause _____________ in soil structure when crop residues are added to soil?

1. decreases

2. stabilization

3. increases

4. compaction

The correct answer is: increases

The addition of crop residues to the soil promotes the activity and growth of soil microorganisms (micros), which have a significant role in enhancing soil structure. When crop residues decompose, they provide organic matter that serves as a food source for these microorganisms. As the microorganisms break down the organic materials, they produce various byproducts, such as glomalin and polysaccharides, which help bind soil particles together. This binding process is critical for improving soil structure, leading to the formation of aggregates. Good soil structure is characterized by porosity, aeration, and improved water retention, which are essential for root growth and overall soil health. Therefore, when crop residues are added to the soil, the increased activity of soil microorganisms leads to stabilization and enhances the overall structure of the soil, thus contributing to increases in soil stability and productivity over time.