Enhancing the Value of Cover Crops through Integration of Row Crop and Cattle Enterprises
While establishing cover crops following grain production helps protect and enhance Iowa’s water quality and the soil profile, cover crops also provide an additional forage resource. To date, most of the research from a livestock perspective has focused on spring grazing of overwintering cover crops. Yet spring grazing of cover crops can be a challenge due to a narrow window of opportunity based on weather implications hindering spring growth, and the desire to get the cash crop established in a timely manner. Thus, there is growing interest in fall grazing of cover crops.
This project will evaluate nutrient quality and potential yield of an oat-cereal rye cover crop when interseeded into standing cash crop as a forage resource for grazing cattle; determine if cover crops still maintain agronomic benefits when grazed; demonstrate integration of an oat-cereal rye cover crop into row crop systems to enhance fall grazing potential for the beef herd; and further develop decision tools to evaluate weather risk, costs, and grazing potential of cover crops.
This project complements an existing project evaluating stocker cattle performance while grazing cereal rye at three ISU outlying research farms (Allee, McNay, and Western). This project focuses on interseeding an oat-rye mix into an existing corn or soybean stand to focus on fall grazing potential. This interseeding will be done in August before a rainfall. Plant stand, forage biomass yield, and nutritional quality will be measured throughout the fall to benchmark the forage availability. In addition, bulk density measurements will be collected at the same two time points to evaluate any soil compaction due to cattle grazing. Cattle will be individually weighed prior to oat-rye mix turnout and after removal from cover crop to determine average daily gain and weight gain per acre. The research will be conducted in the fall of both 2018 and 2019, allowing data to be collected behind both corn and soybean crops at each of the outlying farms.
Cover crop forage quality and quantity varies greatly based on weather patterns, location in the state, seeding dates and competition from the cash crop when interseeded. Table 1 and Figures 1, 2, and 3 demonstrate the variability in nutrient quality of various cover crop samples taken from the outlying farms in the fall of 2018 and 2019 are demonstrated in Table 1 and Figures 1, 2, 3 in the final report (linked, below). The average number of fall grazing days in 2018 was 8 days. Only one field was grazed for 7 days in the fall of 2019. Despite the limited availability of fall grazing days, the cover crops’ nutritional value makes it a high-quality feedstuff and contributes to feed savings for the Iowa beef producer. Thus, the forage availability creates further incentive for cover crops adoption across the state and aids in more efficient use of resources, which can improve both cattle and crop enterprise profitability.
While the amount of fall grazing was limited in this two-year study, fall grazing does not appear to negate the agronomic benefits cover crops are known to provide, such as reducing soil compaction (Table 3) and building soil organic matter (Table 4). However, since many of the agronomic benefits take time to have an impact, a longer assessment is needed to continue to evaluate how grazing can impact the agronomic benefits cover crops can provide.
*Specific to the project alone: Grazing Fall-Seeded Cover Crops with Fall-Calving Cow-Calf Pairs (RFR-A18120), Grazing Fall-Seeded Cover Crops with Stocker Cattle (RFR-A1953)
*Joint publications that include project data: Best Management Practices for Fall Grazing Cover Crops infographic (ILF), Grazing Cover Crops to Avoid Soil Compaction (ILF), Herbicide Use May Restrict Grazing Options for Cover Crops (CROP 3082), Managing Cattle Health Issues When Grazing Cover Crops (IBC 129), A Field Guide to Winter Cereal Rye Forage Quality (ASL R3309), Nitrate and Sulfur in Fall Grazed Cover Crops (ASL R3312), Farmers Experiences with Fall Grazing Cover Crops (IBC 142; in progress), Cover Crop Integration in Iowa (an extension programming evaluation summary; in progress)
Other activities and accomplishments:
- 11 field days, 14 presentations, 7 workshops