Lots must be cleaned regularly and wastes applied to cropland at agronomic rates. When lots are in continuous use, the soil develops a surface seal, minimizing downward percolation. Livestock lots used intermittently or that have been abandoned often pose the most serious risk because the surface seal soon breaks down, allowing nitrate to leach to groundwater. Removal of accumulated organic waste and planting and harvesting crops in abandoned and intermittently used lots is essential to minimize nitrate leaching. Advanced wastewater systems are available to reduce nitrogen.
Research is ongoing to improve efficiency.
Shallow systems with good perennial grass cover help utilize some nitrogen and minimize losses to groundwater. Nitrogen fertilizer should not be applied over the absorption system area. Large lawn and garden areas surrounding the home can be an important source if nitrogen fertilizer applications are not carefully controlled. Fertilizer applications should be no more than required by a lawn or garden. Remember, clippings left on the lawn recycle nitrogen to the soil.