Growing cover crops (CCs) on no-tillage (NT) fields has been widely recommended to regenerate degraded soils after many years of conventionally-tilled, low-intensity crop production. However, major barriers to the adoption of CCs exist in the water-limited areas of the North Central Region including costs of establishing CCs and risk of CCs reducing subsequent grain yields because of reduced soil water at next crop planting. Grazing CCs could provide economic benefits to offset revenue losses when the water use of CCs decreases subsequent grain yields and potentially increased system profitability. However, at this time, there is limited guidance on the optimum CC biomass removal rate for grazed CCs. Current Kansas NRCS recommended stocking rates are based on those developed for native rangelands.
This project will determine sustainable rates of biomass removal with CCs in NT cropping systems in western Kansas. At the Kansas State University HB Ranch near Brownell, KS, different rates of CC biomass removal with grazing will be compared to ungrazed CCs and fallow in a NT winter wheat-grain sorghum-fallow (WSF) cropping system. Cover crops will be grazed in late spring using yearling heifers at appropriate stocking densities to remove 50, 70, and 90% of the available CC biomass. In addition to the study at Brownell, a subset of treatments (ungrazed CCs, 50% CC biomass removal, and 90% CC biomass removal) will be implemented on producer fields near Dorrance, KS to investigate the effects of grazing intensities on soil properties at field scale. We will determine CC biomass production, canopy cover and height, as well as forage nutritive value. Soil samples will be collected to determine soil physical and chemical properties across treatments.
The results of this research will guide recommendations for stocking densities and grazing durations to balance forage use of CCs and soil health. By identifying an optimum biomass removal rate for grazed CCs, farmers and ranchers will be able to maximize livestock gains while maintaining soil health benefits of CCs. Producers will be able to make the most of the CC grazing season to reduce the need for more costly stored forages and delay grazing of native rangelands. Sustainable integration of CC will improve water and air quality by increasing water infiltration and reducing soil water and wind erosion from croplands. By reducing soil loss, soil fertility will be sustained for future generations of farmers and ranchers in western Kansas and throughout the North Central Region.
Project objectives from proposal:
This proposed research will generate information which will improve farm profitability, improve environmental quality, and enhance quality of life. First, by learning the optimum amount of CC biomass removal that balances grazing and soil health goals, farmers will be able to optimize livestock gains while enhancing soil health. This information will provide management guidelines for producers to make the most of CC grazing in their overall livestock operations to reduce the need for more costly stored forages (hay and silage) and delay grazing of native rangelands, allowing for longer rest periods and improved rangeland health. Enhanced soil health with CC grazing is expected to improve water and air quality by increasing water infiltration and reducing soil water and wind erosion. By reducing soil loss, soil fertility will be sustained for future generations of farmers and ranchers.
This research targets farmers using CCs to build soil health and integrate livestock on their croplands. While producers most likely to be directly impacted by the findings of this research will be located in Kansas and nearby surrounding states, the results will be broadly applicable to producers across the North Central Region. In order to measure the outcomes of this research, surveys will be distributed to producers attending field day events to determine their likelihood of adopting grazed CCs in their operations. Additionally, Kansas State University extension agents will also be polled to determine the likelihood of farmers and ranchers in their districts to adopt grazing CCs given the results of this study.