Since nitrate leaches through the sod into the groundwater, the only way to ensure a safe water supply is to control the application of nitrogen to the surface of the ground. The key to good nitrogen management is to match the nitrogen application to the needs of the crop.
Many farmers overlook the nutrient value of their livestock manure.
Manure is very high in nutrient value and should be considered and subtracted from calculations of fertilizer needs. Manure can reduce fertilizer costs and still provide enough nitrogen for crops, while leaving little nitrate to leach down into the groundwater. Manure application practices can also affect the leaching of nitrate into the groundwater. For instance, if the manure is applied sooner than the crop can use it, a large portion of the nitrate can be lost by leaching. To save manure for the best application time, a well engineered and constructed storage unit should be provided.