Illinois Field Crop Applicators Practice Test

What is required for all soil-applied herbicides to effectively move into the soil?

1. Mechanical mixing

2. Precipitation

3. Both mechanical and precipitation

4. Soil temperature regulation

The correct answer is: Both mechanical and precipitation

For soil-applied herbicides to effectively reach the target zone in the soil, movement is necessary. This movement can be facilitated by two primary processes: mechanical mixing and precipitation. Mechanical mixing refers to the physical action of incorporating the herbicide into the soil, which enhances its contact with soil particles and allows it to disperse more evenly. This can be achieved through methods like tillage or using application equipment that can incorporate the herbicide into the top layer of the soil. Precipitation, on the other hand, helps to dissolve and transport the herbicide into the soil profile. Rainfall or irrigation can move the herbicide deeper into the soil where it can effectively work against weeds. Both of these processes are crucial, as herbicides need to be in the soil solution to be taken up by plants or effectively act on weed seeds. This combined requirement highlights the importance of environmental conditions (like rainfall) as well as mechanical methods of soil preparation for achieving effective herbicide action.