Prairie strips, which are strips of herbaceous, perennial plants integrated into agricultural fields, have shown remarkable potential in enhancing soil health more quickly than previously anticipated. Research conducted by scientists from Iowa State University in collaboration with the Soil Health Institute indicates that these strips can boost various soil health measures within a timeframe of just 10 to 12 years. The findings, published in March 2023 in the Journal of Soil and Water Conservation, highlight the significant impact of prairie strips on soil quality while minimally affecting crop production.
Impact on Soil Health Indicators
The study revealed that prairie strips improved eight out of twelve soil health indicators, with notable enhancements in several key areas. For instance, soil aggregate stability showed an increase of up to 80%, indicating a greater ability of the soil to resist erosion. Additionally, microbial biomass, which is crucial for nutrient cycling and carbon sequestration, rose by as much as 54%.
Furthermore, the research indicated that soil organic matter, vital for healthy soil ecosystems, increased by 23%. The ability of soil to retain water also improved, with maximum water-holding capacity rising by 7%. Lead researcher Marshall McDaniel, an associate professor of agronomy at Iowa State, expressed his excitement over these findings, noting that the extent of change observed surpassed expectations.
While aggregate stability and maximum water-holding capacity continued to improve throughout the study, other measures plateaued over time. Notably, microbial biomass showed a slight decline by the end of the study period, emphasizing the need for ongoing monitoring of these variables.
Methodology and Broader Findings
The research utilized a “paired chronoscope” approach, analyzing data from 15 paired sites across four of Iowa’s seven major landforms. Each pair included a prairie strip treatment site and a conventional cropland control, managed primarily in a corn-soybean rotation. Most of the sites were located on private farmland, allowing for practical insights into the benefits of prairie strips.
In addition to immediate soil health improvements, the research highlighted broader ecological benefits. Lead author Cole Dutter, who recently completed his doctorate in sustainable agriculture and soil science, found that changes in microbial communities extended well into adjacent cropland soils. This included elevated enzyme levels that enhance nutrient cycling and carbon storage, potentially increasing nutrient availability for crops and improving overall farm productivity.
The effects of prairie strips were shown to extend more than three feet (up to 1 meter) into adjacent fields, with minimal impact on crop yields. This suggests that integrating prairie strips into farming practices can offer significant ecological advantages without sacrificing agricultural productivity.
Looking ahead, Lisa Schulte Moore, director of ISU’s Bioeconomy Institute, noted that some farmers expressed interest in rotating their prairie strips after ten years to maximize the benefits across their fields. Preliminary research into this concept indicates potential long-term boosts to both soil health and crop yields.
As Dutter prepares for a new faculty position at California State University, Stanislaus, he remains committed to advancing research on prairie strips. He emphasized the importance of understanding whether the benefits observed in the upper soil profile can translate into deeper carbon storage in the soil.
The study’s findings underscore the relatively quick benefits that prairie strips can provide. Notably, the techniques used to measure soil health are accessible and inexpensive, allowing farmers and landowners to assess their soil conditions without requiring specialized scientific training. For instance, aggregate stability can be evaluated using a smartphone app developed by the Soil Health Institute, enabling citizen scientists to engage in soil health monitoring.
The research received funding primarily 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. This collaborative effort highlights the importance of sustainable agricultural practices and their role in enhancing soil health across various landscapes.