Cover Crop Biomass Removal Rates to Optimize Livestock Production and Soil Health in No-Tillage Dryland Cropping Systems

View the project final report

Commodities

• Agronomic: sorghum (milo), triticale

Practices

• Animal Production: grazing management
• Crop Production: cover crops, no-till
• Education and Training: on-farm/ranch research
• Production Systems: dryland farming
• Soil Management: soil quality/health
• Sustainable Communities: quality of life

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 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 Natural Resources Conservation Services (NRCS) recommended stocking rates are based on those developed for native rangelands.

This project was initiated in fall 2022 on a 20-ha producer field in Russell Co., KS to investigate the effects of CC biomass removal rates with cattle grazing on soil health parameters and grain crop yields, and profitability in no-till (NT) dryland cropping systems. The study design was a randomized complete block with three treatments and four replications. The treatments included ungrazed CCs, “talk-half-leave-half” (T-H-L-H, 50% biomass removal), and “graze-out” (G-O, 90% biomass removal). Results showed that T-H-L-H and G-O significantly reduced CC residue amount and height compared to ungrazed CCs but maintained residue cover on the soil surface similar to ungrazed CCs. Cover crop management had no significant effect on soil organic carbon, particulate organic matter, nitrate-N, or P concentrations. However, T-H-L-H somewhat increased soil bulk density compared to ungrazed CCs though both of these were similar to G-O. Soil penetration resistance, wind-erodible fraction, mean weight diameter of water stable aggregates, time-to-runoff, and subsequent grain sorghum yield were unaffected by CC management.

These results suggest that farmers and ranchers may be able to graze CCs at greater intensities than T-H-L-H to maximize livestock gains while obtaining soil health and water quality objectives similar to ungrazed CCs, which could increase adoption of CCs in central and western Kansas. Greater adoption and implementation of cover crops would also benefit water quality protection and improvement efforts in reaching the goals of the approved 9 Element Watershed Restoration And Protection Strategies Plan developed in partnership with Kansas State University, Kansas Center for Agriculture Resources and the Environment, the Kansas Department of Health, and Environment and Environmental Protection Agency. Nevertheless, these observations were made under exceptional drought conditions, so further investigation will be necessary under conditions of average or above average precipitation when wet soils may be more susceptible to degradation by cattle hoof traffic.

For one dryland farmer/rancher in west central Kansas, cover crops have become a staple component of his livestock grazing plan. Cover crops allow him to delay moving cattle to native rangelands in the spring and also move cattle off rangeland earlier in the fall. This  allows longer periods of rest, which has increased rangeland health on his operation. This farmer feels further empowered to implement cover crop grazing on his no-till cropland knowing that his soil health can be maintained or enhanced with proper stocking rates and duration of grazing. For him, grazing cover crops allows him to capture economic value in the form of livestock gains while making steps to enhance the health of his soil.

This research generated 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 adds to 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.