Dairy farmers save money, prepare for regulations using manure as fertilizer

The Issue

Growers have long known that dairy manure water pumped onto adjacent farmland contains useful plant nutrients. However, because it hasn’t been easy to estimate the amounts of nitrogen and other nutrients in the water, farmers have added commercial fertilizer. Under the US EPA's revised Clean Water Act requirements, most dairy farms will have to prepare management plans documenting all plant nutrients applied to fields. Eventually, the revised regulations will require producers to submit documents showing they are applying manure nutrients at appropriate rates. Growers are concerned about the complexity of complying with the new regulations.

What Has ANR Done?

Now, data from the Biologically Integrated Farming Systems (BIFS) program and other UC research projects using flow meters and nitrogen “quick tests” have made it possible for farmers to measure nutrients in the lagoon water. This enables them to reduce or eliminate use of synthetic fertilizers. BIFS is administered by UC's Sustainable Agriculture Research and Education Program (SAREP).

UCCE associate hydrologist Thomas Harter’s project on the impact of dairy waste and nutrient management on groundwater quality was conducted in conjunction with UCCE farm advisor Marsha Campbell Mathews’ project on the use of dairy lagoon water in the production of forage crops. Harter’s and Campbell Mathew's projects laid the groundwork for the dairy BIFS project, involving farmers and pest control consultants as well as UC farm advisors, specialists and other researchers. Field days, workshops, grower surveys and other tools that directly link researchers with farmers have been used extensively in the project.

The Payoff

BIFS team helps dairy farmers reduce inputs, maintain yields

In one on-farm demonstration project, eight BIFS dairy farmers in partnership with UC farm advisors and researchers have optimized the use of animal manure on their forage crops, reducing the use of nitrogen, phosphorus and potassium and lessening the leaching of nitrates into the soil. Cost savings to the growers averaged $55/acre and went as high as $116/acre. In a related project, Harter found an overall 25% decrease in average shallow groundwater nitrate concentration over four years where cooperating dairy farmers were managing the nutrients on their fields.

Clientele Testimonial

“We cut our commercial fertilizer use way back and still managed to maintain our yields. My neighbor has begun to do the same thing. I think there has been a transition in the whole dairy industry.” BIFS dairy farmer Steve Wilbur of SBS Ag,Tulare


Supporting Unit: Sustainable Agriculture

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