Nitrogen Fertilizer Loading to Groundwater in the Central Valley

Nitrate‐nitrogen is the most common pollutant found in the Central Valley aquifer system of California. This project provides a long‐term assessment of past and current potential nitrogen loading to groundwater on irrigated and natural lands across the entire Central Valley of California using a nitrogen mass balance approach; assesses the long‐term implications for groundwater quality in the Central Valley (Sacramento Valley, San Joaquin Valley, and Tulare Lake Basin); evaluates potential best management practices to reduce groundwater nitrogen loading from irrigated lands; and provides a planning tool to better understand local and regional groundwater quality response to specific best management practices and policy/regulatory actions. The project complements other work to assess the vulnerability of Central Valley groundwater to nitrate contamination, sources of nitrate in groundwater, and how to reduce source loading.