Utilizing Beef Stocker Cattle to Enhance the Value of Cover Crops
The increasing popularity of cover crop usage presents a substantial amount of potential forage available to the beef industry that would otherwise be wasted beyond their agronomic purposes. While research has shown the benefits of improved soil health and nutrient retention from cover crops, very limited data is available on utilization of cover crops by beef animals.
Because of the variability of cover crop success and yield from year to year, stocker cattle appear to be a natural fit, offering the flexibility to be purchased and sold depending on forage availability.
ISU Research Farms, Leopold Center for Sustainable Agriculture and the Iowa Beef Center are partners in this project to begin determining the effects of grazing cover crops on cattle performance and soil health. Cover crop plots at the McNay Memorial Research and Demonstration Farm and the Allee Research and Demonstration Farm are involved in the research. Cattle will be individually weighed before being turned out onto the cover crops and after removal to determine average daily gain. Forage yield, forage quality and soil parameters will be measured three times throughout the growing season. The soil and plant health component of this project is being funded by the Iowa Nutrient Research Center.
The key objective of this project was to evaluate the impact on soil health of animal grazing of cover crops in a row cropping system. The results show animal grazing on cover crops in the spring has some effect on soil compaction at the soil surface, especially in wet soil conditions; cover crops contributed to soil carbon in the top six inches; cover crops reduced bulk density, especially at the top six inches, and reduced grazing impact on soil compaction; and cover crops reduced soil NO3-N concentration in the top 12 inches of the soil.
In April, soil samples were taken of the two cover crop plots established in 2015 at the McNay Research and Demonstration Farm. These are being processed and analyzed for total organic carbon, nitrogen, pH and nitrate. Soil moisture measurements at the six-inch depth were taken in April and May. Soil penetration resistance measurements also were taken from the 28-acre plot after grazing, and from the 40-acre plot after the rye crop wilted. Cover crop biomass from the 28-acre plot was collected to determine biomass from grazed and non-grazed plots.
Two experiment sites at the McNay Research and Demonstration Farm were established in 2015, one 40 acres, the other 28 acres. Sub-samples of harvested forage were have been processed and analyzed for total organic carbon (C) and organic nitrogen (N). Soil samples from each experiment site have been processed in the lab for bulk density, pH, C, N, and nitrate-nitrogen (NO3-N) measurements. Soil bulk density data have been recorded for both experiment sites, and chemical analyses of the soil samples for pH, C, N, and NO3-N is in progress. Plant and soil samples have been processed and total C and N measurements performed.
The focus of the soil and plant health component of this project is at the McNay Research and Demonstration Farm. Two experiment sites have been established, one 40 acres, the other 28 acres. Field and lab work got underway in September. This included soil sampling for bulk density, pH, organic carbon, organic nitrogen and nitrate-nitrogen measurements; corn residue on the 40-acre plot and soybean residue on the 28-acre site; soil moisture; and soil penetration resistance. Lab work and data analysis is underway.