Nitrate contamination of groundwater is a widespread problem in California, potentially causing human health problems and contributing to high costs of well remediation, The Fertilizer Research and Education Program (FREP) of the California Department of Food and Agriculture (CDFA) was created in 1990 to advance the environmentally safe and agronomically sound use of fertilizing materials. Since 1991, 51 research and education projects have been funded. Priority cropping systems include fruit and nut orchards on the east side of the San Joaquin Valley and cool season vegetables in the coastal regions of central California. Promising results from these projects are (i) the development of quick diagnostic tools that allow growers to closely monitor crop nutritional status, and (ii) provision of soil and crop fertility knowledge to growers and consultants through a wide variety of educational programs. California's multitude of crops and climates pose a big challenge. With over 200 crops grown in California, it is impossible to develop adaptive research and outreach projects to effectively address every situation, Therefore, FREP's approach has been to concentrate on those farming systems that pose the highest potential threat and where payoffs appear most promising.
