Research from Iowa State University, in collaboration with the Soil Health Institute, reveals that prairie strips can significantly enhance soil health more quickly than previously believed. These strips, composed of 30-100 ft sections of perennial plants integrated within agricultural fields, aim to mimic the ecological benefits of Iowa’s native prairies while minimally affecting crop production.
The study, published in the Journal of Soil and Water Conservation, demonstrates that prairie strips can improve soil health metrics within just 10-12 years. This research marks a significant advancement in understanding the role of these strips in agricultural settings, particularly regarding soil health.
Significant Findings on Soil Health Improvement
The study assessed various soil health indicators and found that prairie strips positively impacted eight out of twelve measures. Notable improvements included:
– Soil aggregate stability, which increased by up to 80%. This measure indicates the soil’s ability to resist erosion.
– Microbial biomass, which saw an increase of up to 54%, highlighting the presence of microscopic organisms crucial for nutrient cycling and carbon sequestration.
– Soil organic matter, which improved by up to 23%, representing the living and decomposed material essential for soil vitality.
– Maximum water-holding capacity increased by up to 7%, enhancing the soil’s ability to retain moisture.
According to Marshall McDaniel, an associate professor of agronomy and the study’s coordinator, the results were unexpectedly positive. “It was an exciting surprise to see the degree of these changes over just a decade or so,” he stated. The findings challenge previous assumptions that such improvements would require much longer periods to manifest, particularly regarding soil organic matter and water-holding capacity.
Broader Implications of Prairie Strips
The research utilized a “paired chronoscope” approach, comparing 15 control and treatment sites featuring prairie strips aged between 2 and 13 years. This methodology allowed researchers to observe changes across various landscapes within Iowa. The study primarily focused on private farmland, and six key aspects of soil health were measured within the top six inches of soil.
Further assessments were conducted along the oldest prairie strip, located at the Neal Smith National Wildlife Refuge near Prairie City. Led by Elizabeth Riecke from the Soil Health Institute, this component contributed valuable insights to the broader North American Project to Evaluate Soil Health Measurements.
Additional findings revealed that microbial community changes extended from the prairie strips into adjacent croplands. These changes included heightened enzyme levels that could enhance nutrient availability for crops and improve carbon storage capabilities. The effects of prairie strips on soil moisture and nutrient availability were observed to extend over 3 feet (approximately 1 meter) from the strips, with minimal effects on crop yields.
As farmers consider implementing prairie strips, Lisa Schulte Moore, director of ISU’s Bioeconomy Institute and a collaborator on the study, noted the potential for rotating these strips after ten years. “Some farmers we have worked with are interested in rotating their prairie strips to spread the benefits across their fields,” she explained. Ongoing research led by Cole Dutter, the study’s lead author, aims to explore this concept further.
Dutter emphasized the relevance of prairie strips in promoting soil health. “Our related projects show that prairie strips are a relatively quick way to build soil health in the top of the soil profile,” he stated. He plans to continue his research on prairie strips as he transitions to a faculty position at California State University, Stanislaus.
The study highlights that the techniques used to measure aggregate stability and water-holding capacity are straightforward and accessible for landowners. “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,” McDaniel added. For instance, aggregate stability can be measured using a smartphone app called Slakes, while maximum water-holding capacity can be determined with simple household items like a funnel and coffee filter.
Funding for the 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. As awareness of the benefits of prairie strips grows, this research underscores the potential for sustainable agricultural practices to enhance both soil health and crop productivity.
