Improving Pasture and Rangeland Management
The ARS pasture and rangeland management research program enhances the utility, function, and performance of rangelands, pastures, forage, and turf agroecosystems while providing ecosystem services. ARS research helps producers improve management decisions and ultimately achieve healthy and productive pastures and rangelands that support rural prosperity, food security, and healthy agroecosystems, as illustrated by the following FY 2019 accomplishments. Hyperlinked accomplishment titles point to active parent research projects.
Low-cost precision technology helps with peak rangeland production. Rangeland producers need timely, reliable, and easy-to-understand information about the condition of their land to make management decisions. Critical information needed for managing grazing cattle productivity include timing of establishment, growth, peak production, and reproduction of various pasture plants. Producers traditionally collect this information during field visits, which are expensive and time intensive. Through extensive field work in dominant ecosystems of the Great Basin and Chihuahuan Desert, ARS scientists in Reno, Nevada, and Las Cruces, New Mexico, determined that inexpensive, land-based, plant phenology cameras can be used to quantify changes in mixed shrub-grasslands and meadow ecosystems. These plant “phenocams” offer producers a powerful way to improve their ability to decide when grazing time is at its peak, the best time to apply herbicides, and when to reduce vegetative fuel loads that increase the risk of wildfires.
An online decision support tool for ranchers provides a county-level forecast of rangeland vegetation. Ranchers must decide yearly whether the forage available on their land is sufficient to support their livestock without impairing the future productivity of the land. To provide data to help ranchers make their decisions, ARS scientists from Fort Collins, Colorado, collaborated with scientists from Colorado State University, the USDA Northern Plains Climate Hub, the National Drought Mitigation Center, and the University of Wyoming to develop the Grassland Productivity Forecast (Grass-Cast; grasscast.unl.edu), an online tool that predicts forage productivity based on recent weather patterns in a given area. Grass-Cast uses more than 30 years of historical forage productivity data and combines it with weather patterns to generate a prediction of future productivity. Grass-cast originally focused on the Northern Great Plains when it launched in May 2018, and its maps and projections are now expanding to cover all of New Mexico and Arizona.
Mineral supplementation increases productivity and profitability of cattle grazing wheat. Giving supplemental feed to grazing cattle is a good way for producers to increase net returns to the livestock enterprise. Wheat pasture is a unique resource in the southern Great Plains because it provides income from both the grain crop and body weight gain by grazing cattle. Given this dual income source, many producers do not supplement the cattle diet with mineral mixtures to increase cattle performance even though mineral analysis has shown that wheat herbage is deficient in calcium. ARS scientists in Woodward, Oklahoma, examined the practice of providing high-calcium and trace mineral mixtures to cattle grazing in a winter-wheat pasture to compensate for the high potassium in wheat herbage. The cattle given supplemental minerals had a 43 percent faster average daily body weight gain than cattle whose diets did not include supplemental minerals, and at the end of the grazing period supplemented cattle weighed as much as 6 percent more than cattle that did not receive supplements. Mineral intakes averaged 4.4 ounces per day, resulting in a cost of supplement per pound of weight gain of $0.09 (assuming a mineral cost of $0.025/ounce). Producers can use this information to improve cattle weight gain and increases the net return to their stocker cattle enterprises.
New cool-season grass cultivars for the southern Great Plains. The hot, dry climate of the southern Great Plains presents a challenge to producers using introduced perennial cool-season grasses. These problems require new plant materials that tolerate the region’s summer weather. An ARS researcher in El Reno, Oklahoma, worked with collaborators to develop two improved grasses, ‘Artillery’ smooth bromegrass and ‘Ammo’ orchardgrass. ‘Artillery’ was registered for sale in Canada, and registration of this cultivar in Europe and Russia is pending. ARS has applied for Plant Variety Protection for ‘Ammo’. These new plants were selected and developed to function under hot, dry growing conditions, and on lower amounts of fertilizer than existing bromegrass and orchardgrass available in North America or Europe. These plants will allow producers in a range of hot and/or dry climates worldwide to grow pastures of high-quality grass where these plants would not grow in the past.
Adjusting fall grazing schedules for finishing cattle increases profits and range sustainability. To maximize economic return, ranchers in semiarid environments must decide each year when to move cattle from rangeland to feedlots for finishing. They traditionally do this in October. The decision is based on expected cattle weight gain given rangeland conditions and market prices, but this forecasting is increasingly challenged by changing climate and highly variable precipitation within and across years. ARS scientists in Cheyenne, Wyoming, and Fort Collins, Colorado, in collaboration with scientists from Argentina and the University of Wyoming, used livestock gain and economic market data from 2003 to 2017, which represented a range of weather conditions, to quantify differences in net revenue based on the date cattle were delivered for finishing. There was wide revenue variability, which highlights the economic challenges for individual operations and rural economies in the region. However, because livestock gains were negligible from early September to the end of the grazing season, removing cattle from pastures in early September can increase net revenue compared with typical October removal. Early removal also provides ecological advantages of more plant residue for soil cover and a longer rest period for healthier vegetation. This information will help regional cattle producers improve their economic and ecological sustainability.
Building climate-resilient landscapes and communities in the Southwest. Weather and climate impacts on southwestern U.S. ecosystems and communities include crop loss, large interannual and spatial variability in precipitation and rangeland production, wildfire, and extreme drought. As members of the USDA Southwest (SW) Climate Hub, ARS scientists in Las Cruces, New Mexico, completed the launch of two online decision support tools, the AgRisk Viewer and the Climate Smart Restoration Tool, and contributed to drought vulnerability assessment projects linked to ecological sites. The SW Climate Hub team also co-authored the 4th National Climate Assessment. Collectively, these efforts will assist farmers, ranchers, foresters, and other land managers in the Southwest strategically adapt to the impacts of extreme weather and climate change.