Research conducted by scientists at Iowa State University, in collaboration with the Soil Health Institute, has revealed that prairie strips can enhance soil health more rapidly than previously anticipated. Prairie strips, which are 30 to 100 feet wide and consist of herbaceous, perennial plants planted within crop fields, aim to replicate the benefits of Iowa’s native prairies while minimally affecting crop yields.
The findings, published in the Journal of Soil and Water Conservation, indicate that these strips can lead to significant improvements in soil health within a span of 10 to 12 years. Specifically, prairie strips have shown considerable enhancements in eight out of twelve soil health indicators, including soil aggregate stability, microbial biomass, and soil organic matter.
Key Findings on Soil Health Improvements
The research highlights several noteworthy changes:
– Soil aggregate stability improved by up to 80%, enhancing the soil’s resistance to erosion.
– Microbial biomass, which plays a crucial role in nutrient cycling, increased by as much as 54%.
– Soil organic matter, essential for healthy soil, rose by up to 23%.
– Maximum water-holding capacity saw an increase of up to 7%, allowing the soil to better retain moisture.
Marshall McDaniel, an associate professor of agronomy at Iowa State who coordinated the study, expressed his surprise at the rapid changes observed, stating, “It has been thought that it would take much longer to see some of these levels of change, especially soil organic matter and maximum water-holding capacity.”
While some indicators plateaued over time, aggregate stability and maximum water-holding capacity continued to improve throughout the study period. The research utilized a “paired chronoscope” method, comparing 15 sites with prairie strips aged between 2 and 13 years to conventional cropland sites. Most of the study locations were on private farmland, and measurements focused on the top six inches of soil.
Broader Implications for Agriculture
Cole Dutter, the lead author of the study and a recent doctoral graduate in sustainable agriculture and soil science, emphasized the broader implications of these findings. Additional research revealed that the microbial communities in the prairie strips extend their benefits deep into adjacent cropland soils, resulting in increased nutrient cycling and potential enhancements in carbon storage.
The effects of prairie strips on soil moisture and nutrient availability extended over three feet from the strips with minimal impact on crop yields. “Some farmers we have worked with are interested in rotating their prairie strips after 10 years to spread the benefits across their fields,” noted Lisa Schulte Moore, director of ISU’s Bioeconomy Institute. This practice could further enhance soil health and crop productivity.
As Dutter prepares to transition to a faculty position at California State University, Stanislaus, he plans to continue his involvement in prairie strips 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.”
The researchers also highlighted that the assessment techniques used in the study are straightforward and accessible to landowners. For instance, aggregate stability can be measured using a smartphone app called Slakes, allowing farmers to evaluate their soil’s resilience against erosion. Additionally, measuring maximum water-holding capacity can be done easily with basic household items.
Funding for this research primarily came from the Foundation for Food and Agriculture Research and the USDA Farm Service Agency, with supplemental support from the National Science Foundation and USDA Hatch funds. The outcomes of this study underscore the potential for prairie strips to serve as effective tools for enhancing soil health in agricultural settings, promoting sustainability and productivity in farming practices across the region.
