Which nutrient management practice helps assess nitrogen sufficiency in crops?

The correct answer is indeed the practice that involves the Pre-Sidedress Nitrate Test (PSNT). This approach is specifically designed to assess nitrogen availability in the soil during the growing season, particularly before side-dressing crops with additional nitrogen. The PSNT measures the amount of nitrate nitrogen present in the soil at a specific point in time, providing a direct indication of whether the current nitrogen levels are adequate for optimal crop growth.

This tool is especially valuable because it allows for adjustments to nitrogen applications based on real-time data, which can lead to more efficient use of fertilizers and reduced environmental impact through minimized nitrogen runoff. This targeted approach ensures that crops receive sufficient nitrogen when they most need it, aligning nutrient management strategies with crop requirements.

Other options, such as crop rotation and cover cropping, focus on soil health and nutrient cycling but do not provide a direct measurement of nitrogen sufficiency at critical growth stages. Soil testing is a broad practice that evaluates nutrient levels, but the PSNT is specifically tailored for assessing nitrogen in growing crops, making it the most relevant choice for the question asked.