Location: Livestock and Range Research Laboratory2019 Annual Report
Objective 1: Develop management strategies to improve rangeland cattle production and ecological stability through effective use of rangeland forage and supplementation. Subobjective 1A: Determine effects of dormant rangeland forage utilization on heifer development, young cow productivity, plant productivity, and species composition. Subobjective 1B: Determine effects of seasonal rangeland forage utilization by steers and heifers during backgrounding on estimates of respiration gas. Subobjective 1C: Determine timing of grazing season and grazing intensity effects on plant productivity, community composition and cattle diet quality. Subobjective 1D: Enhance the accuracy of DNA metabarcoding to assess diet composition. Subobjective 1E: Evaluate factors regulating calf growth on rangelands. Objective 2: Develop management techniques to improve stock water quality in reservoirs by manipulating plant and microbiota abundance. Objective 3: Develop management strategies to restore degraded rangelands and prevent weed invasions. Subobjective 3A: Develop bacterial management strategies to reduce invasive bromes. Subobjective 3B: Improve vegetation outcomes on Conservation Reserve Program lands. Subobjective 3C: Design seed mixes to more consistently meet plant establishment goals during rangeland restoration. Subobjective 3D: Identify seasonal grazing effects on revegetation following Russian olive removal. Objective 4: Identify cool-season perennial grass seed rates that are high enough to prevent weed invasions and low enough to allow establishment of diverse plant communities on disturbed rangelands. Subobjective 4A: Identify cool-season grass seed rates needed to prevent weed invasions and allow seeded shrub establishment during rangeland restoration. Objective 5: Determine the effect of subsurface soil calcium carbonate on available phosphorus, plant biomass, root traits, and mycorrhizal responsiveness. Objective 6: Develop fire management strategies to maintain and improve rangeland stability and livestock production. Subobjective 6A: Determine perennial grass response to timing of fire relative to plant phenology. Subobjective 6B: Quantify drought and post-drought fire effects on plant community composition and productivity. Subobjective 6C: Determine how seasonal timing of fire affects forage quality and cattle grazing preference.
Sustainability of rangeland production hinges on the ability of plant communities to resist change and quickly recover from disturbance (stability) because changes in species composition, forage production, and forage quality fundamentally affect the animal community. Primary forces of change in rangelands are weather, grazing, alien plants, fire and their interactions. This project is designed to improve ecological sustainability and rangeland production by addressing opportunities for increased efficiency of livestock nutrient conversion, mechanisms affecting restoration success and weed control, and interacting effects of management with weather. Improved efficiency of nutrient conversion from dormant rangeland forages is among the most viable options for increasing animal production and minimizing effects on plant communities. We will address this proposition through a series of experiments evaluating plant and animal responses to dormant-season utilization and supplementation strategies. Rangeland restoration methods will be evaluated for direct weed control and mechanisms controlling successful establishment of desirable species. Water manipulations and historical weather data will be included in experiments to determine weather and long-term climate effects on plants and livestock because precipitation is the primary controlling factor for plant productivity and community composition. Fire research will focus on timing of fire (seasonal and phenological) to facilitate development of fire prescriptions that reduce weedy species, promote desirable species, and increase availability of quality forage. Scientists will be integrated across objectives to determine interacting effects of precipitation, grazing, weeds, and fire on soil and plant communities (production, species composition, diversity, propagation, survival) and cattle (weight gain, reproductive performance, diet quality, diet selection). Understanding mechanisms that control rangeland stability and animal responses to alterations in plant communities will assist land managers and livestock producers in improving rangeland integrity (diverse communities dominated by native species) and efficiency of livestock production. Results will also provide scientists greater understanding of the complex interacting forces on rangelands.
This is the first report for this new project which just began in May 2019 and continues research from the previous project, 3036-21630-004-00D, “Adaptive Rangeland Management of Livestock Grazing, Disturbance, and Climatic Variation”. Please see the report for the previous project for additional information. The first year of the Beef Grand Challenge project was initiated through Subobjectives 1A and 1B along with the Fort Keogh NP101 research project entitled Alleviating rate limiting factors that compromise beef production efficiency (Project 3030-31000-018-00D) in collaboration with six ARS locations (Miles City, Montana; Clay Center, Nebraska; El Reno, Oklahoma; Cheyenne, Wyoming; Woodward, Oklahoma; and Grand Forks, North Dakota). Steers and heifers were received from Clay Center in October and received winter grazing and supplementation treatments and are currently following feeding protocols to match El Reno and Clay Center finishing weight targets. The multilocation experiment will continue at least two more years.