California could be example for fertilizer use assistance

California Gov. Jerry Brown signed a bill (AB 2174) the last week of August that would allow technical assistance projects to be eligible as a category of funding under the Fertilizer Research and Education Program (FREP) of the California Department of Food and Agriculture.

FREP was established 20 years ago to address nitrate contamination from agricultural sources in groundwater. FREP is funded by an assessment on fertilizers. The program offers grants for research, education and now technical assistance projects. The idea is to promote more efficient use of fertilizer so as not to cause groundwater contamination.

Earlier this year, a report from the University of California was released indicating that agriculture was responsible for more than 95 percent of the nitrate groundwater contamination in the Tulare Lake Basin and Salinas Valley.

According to the report, the four-county Tulare Lake Basin and the Monterey County portion of the Salinas Valley were examined. About 2.6 million people in these regions rely on groundwater for drinking water. The study area includes four of the nation’s five counties with the largest agricultural production. It represents about 40  percent of California’s irrigated cropland (including 80 different crops) and more than half of California’s dairy herd. Many communities in the area are among the poorest in California and have limited economic means or technical capacity to maintain safe drinking water given threats from nitrate and other contaminants.

Within the study area, human-generated nitrate sources to groundwater include

• Cropland (96 percent of total), where nitrogen applied to crops, but not removed by harvest, air emission, or runoff, is leached from the root zone to groundwater. Nitrogen intentionally or incidentally applied to cropland includes synthetic fertilizer (54 percent), animal manure (33 percent), irrigation source water (8 percent), atmospheric deposition (3 percent), and wastewater treatment and food processing facility effluent and associated solids (2 percent);

• Percolation of wastewater treatment plant (WWTP) and food processing (FP) wastes (1.5 percent of total);

• Leachate from septic system drainfields (1 percent of total);

• Urban parks, lawns, golf courses, and leaky sewer systems (less than 1 percent of total); and

• Recharge from animal corrals and manure storage lagoons (less than 1 percent of total);

• Downward migration of nitrate-contaminated water via wells (less than 1 percent of total).