New research from Iowa State University, in collaboration with the Soil Health Institute, reveals that prairie strips can significantly enhance soil health within a decade, surpassing previous expectations. These strips, consisting of 30 to 100 feet of herbaceous, perennial plants interspersed within agricultural fields, aim to restore ecological benefits similar to those of Iowa’s native prairies while minimally impacting crop yields.
Earlier investigations indicated that establishing prairie strips over approximately 10% of a field could boost biodiversity and pollinator habitats, reduce erosion, and improve water quality. However, the specific effects of these strips on soil health had not been thoroughly examined until this study, published in the Journal of Soil and Water Conservation.
The findings indicate that within a span of 10 to 12 years, prairie strips improved eight out of twelve critical soil health indicators. The most notable improvements included:
– **Soil aggregate stability**, which increased by up to 80%, enhancing the soil’s resistance to erosion.
– **Microbial biomass**, showing an increase of up to 54%, which plays a vital role in nutrient cycling and carbon sequestration.
– **Soil organic matter**, rising by up to 23%, essential for maintaining healthy soils.
– **Maximum water-holding capacity**, with an increase of up to 7%, indicating better moisture retention.
Marshall McDaniel, an associate professor of agronomy at Iowa State and the study’s coordinator, expressed surprise at the magnitude of these changes occurring in such a short timeframe. “It was an exciting surprise to see the degree of these changes over just a decade or so,” he stated.
The research employed a “paired chronoscope” method, comparing fifteen control sites with prairie strips aged between two and thirteen years, representing four of Iowa’s seven major landforms. Most sites were located on private farmland. Researchers assessed six aspects of soil health in the top six inches of soil. A more detailed evaluation occurred at a twelve-year-old prairie strip located at the Neal Smith National Wildlife Refuge near Prairie City, led by Elizabeth Riecke from the Soil Health Institute.
Additional findings from the study highlighted broader benefits. Cole Dutter, who completed his doctorate in sustainable agriculture while working on this project, noted significant changes in microbial communities extending from the prairie strips into adjacent cropland soils. These changes included heightened enzyme levels associated with increased nutrient and carbon cycling, which could enhance nutrient availability for crops and improve carbon storage. Notably, the effects on soil moisture and nutrient availability extended over three feet (approximately one meter) from the strips, with minimal impact on crop yields.
The research underscores the relatively quick benefits of prairie strips, although they occupy only a small portion of a field. Lisa Schulte Moore, director of ISU’s Bioeconomy Institute and a collaborator on the study, mentioned that some farmers are considering rotating their prairie strips every ten years to distribute the benefits throughout their fields. “Cole has initiated some interesting research looking at this idea,” she noted, “showing long-term boosts to soil health and crop yields from rotating strips within fields. We look forward to having more results to share in the next year.”
As Dutter prepares to transition to a faculty position at California State University, Stanislaus, he remains committed to 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. He emphasized the need to explore whether and how these benefits can translate to deeper soil carbon storage.
The study’s measurements of aggregate stability and water-holding capacity utilized straightforward, cost-effective techniques accessible to non-scientists. McDaniel pointed out that these DIY tests can empower landowners to assess soil health in their fields after implementing management strategies like prairie strips. The maximum water-holding capacity method, for example, can be executed with a funnel and coffee filter, allowing farmers and citizen scientists to measure their soil’s capacity to retain water.
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 implications of this research are significant, indicating that prairie strips offer a promising solution for enhancing agricultural sustainability and soil health in Iowa and potentially beyond.
