Making strides in novel manure research with US Dairy’s Net Zero Initiative

The six-year DSWR project is led by Dairy Management Inc. in collaboration with the Soil Health Institute and researchers from Cornell and seven other research institutions. The project is a key undertaking within the U.S. Dairy Net Zero Initiative, which is the first phase in a collective effort by dairy organizations to achieve the industry’s 2050 environmental stewardship goals, including greenhouse gas neutrality.

As part of DSWR, researchers around the United States are studying manure and soil health management systems on commercial and research farms in major dairy regions. They are examining how these new strategies may contribute to greenhouse gas reduction, crop yield, water quality improvement and forage quality.

In New York, NMSP Postdoctoral Research Associate Jasdeep Singh is conducting this research under Quirine Ketterings, Cornell professor of nutrient management in the Department of Animal Science and director of NMSP.

At Noblehurst Farms, the outcomes of various soil health management systems (SHMS) are compared to a more conventional soil nutrient management approach. 

There are five different nutrient management strategies involving liquid dairy manure and solid-manure based products, full-width tillage, strip tillage, fallow and winter cover cropping. The goal is to determine whether new soil health practices and novel manure products can help farmers accomplish the industry’s environmental stewardship goals in an economically sustainable way– maintaining yield while decreasing dairy’s environmental impact. Novel manure products used in the field trials include both flocculated solids (manure which has been combined with a flocculation agent that causes larger particles to sink in the solution and separate from the liquid) and evaporative solids (manure which has had the moisture removed via evaporation). 

“What we hope to glean from this project is more information on how we can better fine tune our production practices, how we are utilizing the manure, whether we need to top dress with nitrogen– we are trying to be more efficient with our resources,” Noble said.

The use of manure solids is expected to reduce emissions given that the nutrients are in organic form (not easily lost through gaseous transport) and lighter in weight (easier to transport without the liquid). The lighter weight and easier transport allows solid manure application in fields that are not accessible to liquid manure spreading.

In 2022, the first year of manure application, liquid dairy manure showed the highest greenhouse gas emissions followed by manure solids, but the plots that received liquid dairy manure yielded considerably higher. In 2023, greenhouse gas emissions and yields were similar among all five treatments, reflecting a dry year. 

So far, soil health indicators such as soil carbon and water infiltration have been unaffected by treatments but this may change in future years. “Soil health builds over time,” Singh said. “This is why the project is conducted over six years.” 

The team is out at the farm taking greenhouse gas emission measurements at least once a week, so the database continues to grow.

“Manure is an asset to dairy farmers and if manure solids can improve soil health and crop productivity with less of an environmental footprint, these new manure technologies can be promoted in the region,” Singh said. 

Madeline Hanscom is a writer for the Nutrient Management Spear Program.