Research from Iowa State University, in collaboration with the Soil Health Institute, highlights the rapid benefits of implementing prairie strips for enhancing soil health. These strips consist of herbaceous, perennial plants planted within crop fields, measuring between 30 to 100 feet. The study indicates that prairie strips can significantly improve various indicators of soil health faster than previously anticipated.
The findings, published in the Journal of Soil and Water Conservation, demonstrate that prairie strips can enhance soil health measures within a period of just 10 to 12 years. Specifically, the research revealed that these strips positively affected eight out of twelve soil health indicators. Notably, the improvements include a remarkable increase in soil aggregate stability by up to 80%, microbial biomass by up to 54%, soil organic matter by up to 23%, and maximum water-holding capacity by up to 7%.
Marshall McDaniel, an associate professor of agronomy at Iowa State, coordinated the study and expressed surprise at the rapidity of these changes. “It was an exciting surprise to see the degree of these changes over just a decade or so,” he remarked.
Significant changes continued to emerge throughout the study. Measures such as aggregate stability and maximum water-holding capacity showed consistent improvement, while microbial biomass and soil organic matter plateaued towards the end of the observation period.
The research employed a “paired chronoscope” approach, utilizing 15 paired control and treatment sites in Iowa, with prairie strips ranging from 2 to 13 years old. Each site consisted of a prairie strip treatment alongside a conventional corn-soybean rotation control. Most of the sites were located on private farmland, allowing for relevant real-world applications.
A more thorough assessment of soil health was conducted at the Neal Smith National Wildlife Refuge near Prairie City, focusing on the oldest prairie strip, which had been in place for 12 years. Elizabeth Riecke, a scientist from the Soil Health Institute, led this component of the research, which is part of a broader initiative to evaluate soil health measurements across North America.
The research also illuminated broader benefits associated with prairie strips. Cole Dutter, who earned his doctorate in sustainable agriculture while working on this project, led the study and related projects examining the wider aspects of soil health under prairie strips. Findings indicated that changes in microbial communities extended beyond the prairie strips into adjacent cropland soils, enhancing nutrient cycling and carbon storage.
The positive effects of prairie strips on soil moisture and plant-available nutrients were found to extend more than 3 feet (up to 1 meter) from the strips, all while minimally affecting crop yields. This confirms the potential for prairie strips to serve as a sustainable agricultural practice that balances ecological benefits with agricultural productivity.
While the research highlights the quick benefits of prairie strips, researchers note that these strips only occupy a fraction of a field. “Some farmers we have worked with are interested in rotating their prairie strips after 10 years to spread the benefits across their fields,” said Lisa Schulte Moore, director of Iowa State’s Bioeconomy Institute.
As Dutter prepares to transition to a faculty position at California State University, Stanislaus, he intends to continue his involvement in prairie strips research. “Our related projects show that prairie strips are a relatively quick way to build soil health in the top of the soil profile,” he explained. “We think there is a lot of potential to expand these benefits throughout fields and even improve yields.”
The techniques used in this study for measuring aggregate stability and water-holding capacity are accessible and inexpensive, enabling landowners to evaluate soil health independently. “These DIY tests are great tools that landowners can use to assess soil health on their own fields after implementing management changes like prairie strips,” stated McDaniel.
Aggregate stability, which showed the most significant improvement, can be measured with a smartphone app, while maximum water-holding capacity can be assessed using simple materials such as a funnel and coffee filter.
Funding for this research primarily came from the Foundation for Food and Agriculture Research and the USDA Farm Service Agency, with additional support from the National Science Foundation and USDA Hatch funds. The findings underscore the potential of prairie strips as a viable practice for enhancing soil health and promoting sustainable agriculture in Iowa and beyond.
