Nitrate-nitrogen losses to groundwater from rural and suburban land uses

Abstract

ABSTRACT: Nitrate-nitrogen (nitrate-N) losses to groundwater from septic systems, forests, home lawns, and urea- and manure-fertilized silage corn were quantified and compared during a 2-year study. The septic system and all silage corn treatments had annual flow-weighted concentrations of nitrate-N in excess of 10 mg/l for at least 1 of the 2 years. In contrast, forest and both fertilized and unfertilized home lawn treatments generated flow-weighted nitrate-N concentrations of less than 1.7 mg/l. Annual losses ranged from greater than 70 kg/ha of nitrate-N from silage com treatments to less than 1.5 kg/ha from unfertilized home lawns and forest. The results demonstrate the importance of unfertilized land use types in maintaining aquifer water quality; they also suggest that replacing production agriculture with unsewered residential development will not markedly reduce nitrate-N losses to groundwater.