Why is regular sampling and calibration important when using manure as a nutrient source?

Regular sampling and calibration are critical when using manure as a nutrient source because manure can have highly variable nutrient content. Factors such as animal diet, storage conditions, and the method of application can all influence the nutrient levels in the manure. By conducting regular sampling, nutrient management consultants can obtain accurate data on the concentrations of nitrogen, phosphorus, potassium, and other essential nutrients in the manure. This information is vital for farmers to accurately assess how much manure to apply to meet crop nutrient needs without risking over-application, which could lead to nutrient runoff and environmental issues. Calibration further ensures that application equipment delivers the correct amount, optimizing crop yield and minimizing waste. Thus, understanding the variable nutrient content leads to more effective nutrient management practices and improved cropping outcomes.