New organic farming study tackles questions of soil health, economics and more, with input from farmers

Professor Kathleen Delate (left), Iowa State, and soil scientist Sabrina Ruis, USDA ARS, discuss findings during a field day at the Long-term Agroecological Research study site near Greenfield, Iowa. 

AMES, Iowa — As prices for organic products continue to rise and demand stays strong, farmers have many questions about the costs, benefits and potential profits represented by organic farming methods. 

A new, two-year project led by Iowa State University builds on decades of work at two organic research sites in Iowa. It will also add a third on-farm research site that brings a new layer of engagement with interested stakeholders. 

The project will use modeling and field research to dig deep into the long-term impacts of organic methods that include crop rotations, no-till practices and use of composted animal manure for fertilizer. Researchers will assess impacts on yields, deep soil carbon storage, greenhouse gas emissions, nutrient cycling and loss, farm economics and more. 

Kathleen Delate, professor of horticulture and agronomy and extension organic specialist, is coordinating the wide-ranging study. She will work closely with a research team that includes soil scientist Sabrina Ruis at the USDA Agricultural Research Service’s National Laboratory for Agriculture and the Environment (NLAE) in Ames. The research is funded by the Foundation for Food and Agriculture Research and The Organic Center.

“A number of studies, including research at Iowa State, show the economic benefits that can be realized from organic cropping systems over conventional corn-soybean systems,” Delate said. “This new research will build on and update some of that work to help provide answers to farmers’ pressing questions about financial risks and returns.” 

Delate oversees research for the Long-Term Agroecological Research (LTAR) study at the Neely-Kinyon Research and Demonstration Farm near Greenfield, Iowa – one of the new project’s three locations. Established in 1998, the LTAR study is one of the country’s longest-running scientific studies of organic cropping systems. 

Ruis leads work on the study at the USDA ARS Organic Water Quality (OWQ) research site, the second location and a 10-year experimental study site near Ames originated by the late ARS soil scientist Cindy Cambardella. These two sites have controlled field plot comparisons with adjacent conventional plots. 

Earlier research at the LTAR and OWQ sites have documented small gains in soil health indicators in the organic plots over time in the top layers of soil (1 to 6 inches) compared to the conventional plots. The new experiment will look deeper in the soil profile at a suite of soil health indicators. These comparisons will delve into carbon levels along with soil fertility and structure, water-holding capacity and soil biology. 

The new grant also supports research at a new location through a unique collaboration with Grow: Johnson County, a farming program of the Iowa Valley Resource Conservation & Development that helps support socially disadvantaged farmers in the Iowa City area. 

The Grow Johnson County Farm will provide opportunities for farmer-scientist knowledge exchange, including on organic nutrient management planning, soil testing and no-till methods for vegetable crops. 

“Our project has been informed by on-going dialogue with organic and transitioning farmers,” Delate said. “Their top questions for research are always about soil health and economics. This study prioritizes those questions, using several approaches. Including citizen science at a working farm location has potential to add significant value to the long-term experimental plot work I’ve primarily done. It also adds complexity. We will all learn in the process, and that’s part of our goal.” 

Another important area of learning, according to Delate and Ruis, will be to explore the capacity of a popular farm-level modeling tool to reflect organic methods. They plan to use the CarbOn Management and Emissions Tool (COMET), developed by USDA’s Natural Resources Conservation Service and others, to help assess the impacts of different management approaches on processes such as soil carbon storage and greenhouse gas production over time.  

“COMET has mostly been used to evaluate conventional agricultural practices,” Ruis said. “We want to make it more useful as a tool to help analyze and predict changes tied to organic farming practices.” 

Other members of the research team include: 

  • Thanos Papanicolaou, director, USDA NLAE;
  • John Kovar, soil scientist, USDA NLAE;
  • Ken Wacha, hydrologist, USDA NLAE; 
  • Laurie Nowatzke, rural sociologist, USDA NLAE; 
  • Ann Johanns, program specialist in economics, ISU Extension and Outreach; and 
  • Jason Grimm, executive director, Grow: Johnson County Farm. 

The team will hold field days each year, with the first planned to discuss and demonstrate soil testing at the Johnson County farm in June. Results of the project will inform development of an Iowa State University Extension and Outreach publication focused on climate-smart organic farming practices. 

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