Iowa Pesticide Applicator Practice Exam

Which soil characteristic increases the soil's ability to hold water and pesticides?

1. Soil texture

2. Organic matter content

3. Geological structure

4. Soil color

The correct answer is: Organic matter content

The ability of soil to hold water and pesticides is significantly influenced by its organic matter content. Organic matter improves soil structure, enhancing its porosity and aggregation, which allows for better water retention. This increased water-holding capacity is crucial for both maintaining soil moisture for crops and ensuring that pesticides remain in the soil where they can be effectively taken up by plants. In addition to enhancing water retention, organic matter can also increase the cation exchange capacity of the soil. This means that the soil can hold onto more nutrients and pesticides, allowing for more efficient use and reduced leaching into groundwater. Therefore, managing organic matter content is essential for improving soil health and optimizing the effectiveness of both water and pesticide application.