UC spotlights solutions to dairy water pollution challenges

The Issue

Milk is California's number one agricultural commodity, with a farmgate value of more than $5 billion annually. Although the state has fewer dairy farms than it did 20 years ago, the average herd size has increased. Dairy producers are faced with increasing scrutiny and more stringent regulations.

In May 2007, the Central Valley Regional Water Quality Control Board adopted new dairy “waste discharge requirements” that impose stringent nutrient management and monitoring practices on the region’s 1,500 dairies.

What Has ANR Done?

UC ANR researchers have shown that improper dairy waste management and failure to recycle manure nutrients to cropland at the correct rate and time of year have led to water pollution – leading to contamination of groundwater with nitrate and salts in some parts of the Central Valley. In a recent ANR publication, UC Cooperative Extension (UCCE) specialist Stu Pettygrove, UC Cooperative Extension farm advisors, and other researchers have identified the environmentally beneficial measures progressive dairy producers have adopted to minimize dairy water quality impacts on dairies of all sizes.

The Payoff

UC publication helps policymakers and lenders

A new UC publication, California Dairies: Protecting Water Quality, outlines key management practices that protect surface and groundwater quality. The guide is aimed at lending institutions, consulting engineers and crop management companies that work with dairy producers, as well as regulatory bodies like county environmental health departments and regional water quality control boards. Because each dairy is different, the guide describes a variety of management measures and summarizes four critical components that must be in place to protect water quality.

Publication co-authors include Pettygrove, Patricia L. Ristow, former postgraduate researcher at UC Davis; Deanne M. Meyer, UCCE livestock waste management specialist, UC Davis; David Lewis, watershed management advisor, UCCE, Sonoma, Marin and Mendocino counties; Nyles Peterson, dairy advisor and county director, UCCE, San Bernardino County; and Janet C. Broome, area plant pathologist, UCCE, Sacramento, Yolo and Solano counties.

The 16-page guide was produced with funding from the California Department of Food and Agriculture's "Buy California" Initiative, the USDA, the US-EPA Clean Water Act, and UC Sustainable Agriculture Research and Education Program (SAREP). It was developed through UC SAREP's Biologically Integrated Farming Systems program (information at sarep.ucdavis.edu/bifs/). Free copies of the guide, ANR Publication 21630, are available through Tiva Lasiter at tlasiter@ucdavis.edu, or phone (530) 752-0190.


Supporting Unit: Sustainable Agricultural Research & Education Program

Bev Ransom or Lyra Halprin
SAREP, One Shields Ave., Davis, CA 95616-8716

Bev Ransom, baransom@ucdavis.edu, 530-754-8546
Lyra Halprin, lhalprin@ucdavis.edu, 530-752-8664