Recent research from Iowa State University reveals that prairie strips can enhance soil health much faster than previously anticipated. Collaborating with the Soil Health Institute, scientists found that these strips, composed of 30-100 foot sections of perennial plants interspersed within crop fields, can significantly improve soil quality in just 10 to 12 years.
The study, published in the Journal of Soil and Water Conservation, highlights how establishing prairie strips in around 10% of a field can lead to notable benefits such as increased biodiversity, enhanced pollinator habitats, reduced erosion, and improved water quality. Until now, the impacts on soil health had not been thoroughly explored.
The research identified significant improvements in eight out of twelve soil health indicators, with particular enhancements in crucial areas. The most notable changes included a rise 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, expressed enthusiasm over the findings, stating, “It was an exciting surprise to see the degree of these changes over just a decade or so.” He emphasized that expectations were for these changes to take much longer, particularly regarding soil organic matter and water retention capabilities.
Long-term Benefits and Methodology
The research employed a “paired chronoscope” approach, examining 15 pairs of control and treatment sites. These sites featured prairie strips ranging from 2 to 13 years old and represented four of Iowa’s seven major landforms. Each pair included a prairie strip treatment alongside a conventional cropland control managed in a corn-soybean rotation. Most sites were located on private farmland.
In the study, six soil health aspects were measured within the top six inches of soil. A broader assessment was conducted at the oldest prairie strip, located at the Neal Smith National Wildlife Refuge near Prairie City, Iowa. This portion of the research was led by Elizabeth Riecke, a scientist with the Soil Health Institute, as part of its North American Project to Evaluate Soil Health Measurements.
The study also revealed broader benefits, with lead author Cole Dutter noting significant changes in microbial communities that extended from the prairie strips into adjacent cropland soils. These changes included elevated enzyme levels, which are associated with improved nutrient cycling and carbon storage. This suggests potential increases in nutrient availability for crops and enhanced carbon sequestration.
Furthermore, the impact of prairie strips on soil moisture and plant-available nutrients extended more than three feet (up to one meter) from the strips, all while showing minimal effects on crop yields.
Future Research Directions
While the research confirms the rapid benefits of prairie strips, it also indicates that these strips only represent a small portion of the field. Some farmers have expressed interest in rotating their prairie strips after ten years to distribute the benefits across their fields. McDaniel mentioned that Dutter has initiated studies exploring this concept, which may reveal long-term boosts to soil health and crop yields from rotating strips.
As Dutter transitions to a faculty position at California State University, Stanislaus, he plans to continue his involvement in prairie strip research. He stated, “Our related projects show that prairie strips are a relatively quick way to build soil health in the top of the soil profile.” There is also an interest in understanding how these improvements might affect deeper soil layers.
The researchers emphasized that the methods used to measure aggregate stability and water-holding capacity are straightforward and inexpensive, making them accessible to non-scientists. McDaniel highlighted the effectiveness of these DIY tests, which landowners can utilize to evaluate soil health following the implementation of management changes like prairie strips. For instance, aggregate stability can be assessed using a smartphone app called Slakes, while maximum water-holding capacity can be measured using simple tools like a funnel and coffee filter.
Funding for this comprehensive study was primarily provided by 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.
As the conversation around sustainable agriculture continues to evolve, this research underscores the promising potential of prairie strips in enhancing soil health and supporting agricultural productivity.
