Soil health and ecological resilience of no-till, organic, and mixed-crop livestock systems in eastern Washington State

Authors: DAVIS, ALEXANDRA - Washington State University; CARPENTER-BOGGS, LYNNE - Washington State University; SMITH, KATHERINE - Washington State University; WACHTER, JONATHAN - Washington State University; Heineck, Garett; Huggins, David; REGANOLD, JOHN - Washington State University

Submitted to: Agriculture, Ecosystems & Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/28/2025
Publication Date: 4/26/2025
Citation: Davis, A.G., Carpenter-Boggs, L., Smith, K.L., Wachter, J.M., Heineck, G.C., Huggins, D.R., Reganold, J.P. 2025. Soil health and ecological resilience of no-till, organic, and mixed-crop livestock systems in eastern Washington State. Agriculture, Ecosystems & Environment. 388. Article 109639. https://doi.org/10.1016/j.agee.2025.109639.
DOI: https://doi.org/10.1016/j.agee.2025.109639

Interpretive Summary: Modern agriculture has been successful due to specialization in crop or animal production, mechanization, and heavy reliance on synthetic fertilizers and pesticides. The Palouse Watershed in eastern WA State is emblematic of this general portrayal of agriculture and often consists of a three-year rotation with a heavy emphasis on wheat production. While producing some of the largest per-acre wheat yields in the US, negative impacts on soil health and natural systems are widespread. A nine-year study focussing on alternative cropping systems to reduce soil erosion and improve soil health was conducted with results directly applying to the Palouse region, with further implications to agriculture systems across the US. Alternative cropping systems included 1) no-till cropping, 2) a no-till system that included livestock grazing, 3) an organic cropping system that focussed on grain production and livestock grazing, and 4) an organic hay production system. Each system was measured to determine its impact on ecological resilience, which measures crop productivity, economic stability, and changes in soil health. The organic hay system had the greatest average economic returns and was the only system that maintained organic carbon in the soil. Both organic systems maintain a healthier soil pH compared to the conventional no-till systems. Overall these results suggest the need to increase the incentivization of perennial crops into annual cropping systems and highlight some benefits of organic agroecosystems. This research directly applies to farmers and research efforts in the Palouse region but also has implications for cropping systems and modeling research across the US.

Technical Abstract: Combining concepts of soil health and ecological resilience theory provides a useful framework for assessing and identifying sustainable soil management strategies. Major soil health concerns globally and in the Palouse region of eastern Washington State include erosion, soil organic matter (SOM) loss, and acidification. Alternative cropping systems have the potential to improve these areas of soil health through practices such as no-tillage, diversified crop rotations, and reduced chemical inputs. Here, we report on a 9-year study (2012-2020) examining four alternative farming systems in the Palouse and their impacts on soil health and ecological resilience, accounting for soil erosion, SOM depletion, acidification, and financial performance. The four systems included (i) a no-till system (NT) using a typical 3-year spring pea-winter wheat-spring wheat rotation with conventional herbicide and fertilizer use; (ii) a mixed crop-livestock system (MIX) using a 3-year pea-winter wheat-spring wheat rotation with livestock integration and reduced herbicide and fertilizer use; (iii) an organic system that integrates sheep and intercropping with three years of alfalfa/grass hay and six years of grain cereals and legumes (ORGcrop); and (iv) an organic system that integrates sheep into an eight-year rotation with six years of alfalfa/grass hay and two years of grain cereals and legumes (ORGhay). All four farming systems were above the maximum ecological resilience threshold for soil erosion, below the minimum threshold for soil organic carbon (SOC) content, above the minimum threshold for acidification, and above the minimum threshold for economic performance. In terms of erosion control, NT performed the best, followed by ORGhay, MIX, and then ORGcrop. In terms of carbon sequestration, ORGhay performed the best as it was the only system to not decrease in surface (0-15 cm) SOC. With acidification, ORGcrop and ORGhay performed better than NT and MIX at the surface (0-7.5 cm), but all farming systems were similar when considering 0-30 cm. With economics, ORGhay had the highest average net returns across the nine growing seasons, followed by ORGcrop, MIX, and then NT, with all four systems hypothetically outperforming a typical conventional tillage farm in the area. Although not perfect, ORGhay had no major tradeoffs and overall performed the best, having similar or improved ecological resilience in all areas measured compared to the other three cropping systems. Our data support the need to incentivize Palouse farmers to integrate perennial crops, such as alfalfa and forage grasses, into their farms and convert some of their farm fields to organic like ORGhay.