Nutrient management plans help protect water bodies by reducing runoff of which nutrients?

• A. Calcium and magnesium
• B. Sodium and chloride
• C. Potassium and sulfur
• D. Nitrate and phosphate

Answer: (D)

Reducing nutrient runoff to water bodies focuses on nitrogen and phosphorus because these nutrients drive eutrophication, leading to algal blooms and oxygen depletion that harm aquatic ecosystems. Nitrate, a common form of nitrogen, is highly soluble and easily leaches from soil or runs off with water, reaching streams and groundwater. Phosphate, the form of phosphorus, binds to soil but can be carried in rainfall runoff, especially when soils are disturbed or erosion occurs, and it fuels rapid algae growth. Nutrient management plans specifically target these two nutrients to minimize inputs from fertilizers, manure, and crop residues. Other minerals like calcium, magnesium, potassium, sulfur, sodium, and chloride influence water chemistry or come from different pollution sources, but they do not drive eutrophication in the same way nitrate and phosphate do.