Nitrogen Regulations in California and the Certified Crop Adviser’s Role By MARK CADY | Senior Environmental Scientist, California Department of Food and Agriculture, Fertilizer Research and Education Program and JEROME PIER | Chair, Western Region Certified Crop Advisers Association
California Certified Crop Advisers (CCAs) are an integral part of the nitrogen management compliance picture (all photos by Vicky Boyd.)
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n the last 10 or more years, water quality regulations that address nitrate in groundwater have expanded dramatically. Starting in 2012, the regulatory agencies charged with protecting California’s water quality have increased their scrutiny of and demands on agriculture. So, it is essential for crop consultants to understand the regulations and how regulations affect their customers.
Regulatory History
The challenges associated with nitrate in groundwater and its sources have been recognized for at least a generation. In 1987, the California State Legislature directed the State Water Resources Control Board to prepare a report on nitrate contamination in drinking water. The convened expert panel reported that agriculture was likely an important contributor to nitrate in groundwater. In 2012, however, the regulatory 4
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landscape changed dramatically. First, a major study of nitrate in California drinking water was published by UC Davis. This sprawling effort, titled Addressing Nitrate in California’s Drinking Water, focused on the Tulare Lake Basin and the Salinas Valley. The multi-volume report was produced by the UC Davis Center for Watershed Sciences. It showed that nitrate problems would likely worsen for the next several decades and that most nitrate currently in drinking water wells was applied to the surface decades earlier. An important conclusion of the report was that agricultural fertilizers and animal wastes applied to cropland are by far the largest regional sources of nitrate in groundwater. Thus, in the last decade, the State and Regional Water Boards have been more assertive in regulating agricultural contributions to groundwater nitrate. The Central Valley Irrigated Lands Regulatory Program (ILRP) started in the September / October 2021
first part of this century with a focus on pesticides in surface water. That focus expanded in 2012 when the ‘Waste Discharge Requirements for the Eastern San Joaquin River Watershed (ESJ) General Order’ was first adopted by the Central Valley Regional Water Quality Control Board (CVRWQCB). This order required grower reporting of nitrogen fertilizer applied to cropland and estimates of the nitrogen removed with harvested crops, so the efficiency of nitrogen fertilizer use could be calculated. Growers record this information in their Nitrogen Management Plans (NMPs) as specified by the CVRWQCB. The reporting of NMP data was carried out through the ESJ Water Quality Coalition, a grower-led intermediary that anonymized the data and provided statistical analysis on a township basis. A component of the statistical analysis is identification of outlier values (i.e., parcels where the nitrogen efficiency
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