Partnering with Dairies to Boost Clean Water

The California dairy industry produces 20% of all milk produced in the U.S., making it the top milk producing state in the country. The industry also generates $25 billion in processed milk sales and about 30,000 on-farm jobs. Unfortunately, extensive milk production in California also comes with a significant environmental cost. According to experts, nitrates from dairies are one of the largest sources of groundwater contamination in California.

Many communities throughout California face potential health risks and financial burdens from contaminated groundwater used for drinking. In California, there are more than 200 public water systems that rely primarily on groundwater contaminated with nitrates. Contamination prevention is necessary to protect these groundwater supplies.

The problem is particularly acute in the Central Valley where a vast majority of the state’s dairies reside and where the long-term application of cow manure to crops has contributed to extensive groundwater degradation. California is home to more cows than any other state — with the state’s nearly 2 million cows producing as much waste each year as California’s entire human population. If not managed effectively, the resulting nitrogen poses a serious threat to water quality and the health of millions of Californians.

To protect water quality, dairies need economically-viable solutions that enable them to better track, more precisely apply and more easily export their manure nutrients.

Transforming Dairy Waste into a Clean-Water Ally

Video: Senior Project Manager John Cardoza discusses the water quality, water efficiency and crop benefits of Sustainable Conservation’s liquid-manure drip irrigation pilot project.

Video: Senior Project Manager John Cardoza discusses the water quality, water efficiency and crop benefits of Sustainable Conservation’s liquid-manure drip irrigation pilot project.

Sustainable Conservation is championing a promising new approach to managing dairy waste that increases groundwater health: drip irrigation.

Dairy producers use water to keep their facilities and cows clean, resulting in a lot of excess nutrient-rich water. Applying these nutrients to feed crops as organic fertilizer has been practiced for a long time. The nutrient-rich water, however, needs to be applied in a balanced way so that crops absorb 100% of nutrients and prevent the leaching of excess nutrients into groundwater.

That’s why Sustainable Conservation teamed up with De Jager Farms in the San Joaquin Valley and Netafim USA, which makes irrigation equipment, to pilot a liquid-manure drip irrigation system that promises a trifecta of benefits for farmers and local communities: reduced nutrient leaching, improved water efficiency and increased crop yields.

Last year, our manure drip system helped De Jager Farms increase their nitrogen-use efficiency by more than 50%, reduced water use by 30% and increased crop yields on the corn it grows to feed its cows by 20%.

Growing the Practice

We believe our efforts in partnership with California’s dairy industry will stimulate the development and adoption of this innovative technology that enables dairy producers to ensure crop yield and quality while increasing their water use efficiency and improving their ability to meet federal and state water quality regulations. Doing so will help the California dairy industry move from being seen as a major contributor to serious water problems in California’s Central Valley to showing they are contributing to the solution.

Recognizing the potential for this technology, the U.S. Department of Agriculture, Natural Resources Conservation Service awarded Sustainable Conservation a Conservation Innovation Grant to demonstrate the technology on new sites in California’s San Joaquin Valley.


  • On our Central Valley pilot project, increased crop nitrogen use efficiency by over 50%, cut water use by 30% and increased crop yields by 20%



De Jager Farms

Natural Resources Conservation Service

Netafim USA



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