Certified Crop Advisor Practice Exam

Which practice is recommended for weed control within a crop rotation system?

1. Using the same herbicide annually

2. Crop diversification

3. Planting cover crops

4. Reducing tillage

The correct answer is: Crop diversification

Crop diversification is a highly recommended practice for weed control within a crop rotation system. By rotating different crops, farmers can interrupt the life cycles of weeds that may have become adapted to specific crops and herbicides. Each crop may have different planting dates, growth habits, and methods of canopy establishment, which can outcompete weeds in unique ways. This variation reduces the risk of weed populations becoming established and can lead to a decrease in overall weed pressure. Crop diversification also opens up the opportunity to use varying management practices tailored to different crops, potentially including different herbicide modes of action. This not only aids in effective weed management by reducing reliance on any single herbicide, which can lead to resistance, but it also promotes a more balanced agroecosystem. In contrast, using the same herbicide annually runs the risk of weed resistance and reduced effectiveness over time, while planting cover crops and reducing tillage serve specific purposes in enhancing soil health and preventing erosion but may not directly address weed pressures as effectively as crop diversification does when considered as a primary weed management strategy.