California is the top milk-producing state, accounting for 21 percent of the milk produced in the United States. With that comes responsibility to find innovative solutions for managing cow manure while ensuring food and water safety and security – and California farmers and ranchers remain on the forefront in helping find new agriculture technologies that lead to environmental solutions.
The leadership of our farmers is highlighted in “Subsurface Drip Irrigation System Utilizing Dairy Manure Effluent,” a report recently released by Sustainable Conservation that details their work on several California dairies. The report describes how using subsurface drip irrigation (SDI) modified to apply liquid manure can save water, protect groundwater quality through precision nutrient application, and reduce irrigation-related greenhouse gas emissions.
The report provides information and recommendations for using manure subsurface drip irrigation (manure SDI) on dairies as well as resource links for deeper-level details. Some highlights include:
- Manure SDI provides dairies with a new tool to help improve water resiliency and water quality for their communities.
- Most of the manure SDI fields produced yields similar to flood-irrigated fields but using less water, measured as yield per acre-inch of water applied.
- Manure SDI fields generally resulted in less nitrogen applied and greater nutrient-use efficiency, as measured by pounds of nitrogen applied per ton of yield. Similarly, the manure SDI fields received less magnesium, which is an emerging environmental concern.
- Liquid manure has a lot of solid particles, so the effectiveness of pre-system solid separation will directly influence manure SDI performance.
- With the Environmental Quality Incentives Program (EQIP) cost-share support in California, switching to manure SDI results in a positive change in net income of $96.95 per acre.
CDFA’s Office of Environmental Farming and Innovation was among the many partners and subject matter experts that Sustainable Conservation brought together for this work.