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ARS Home » Plains Area » Miles City, Montana » Livestock and Range Research Laboratory » Research » Research Project #436412

Research Project: Development of Management Strategies for Livestock Grazing, Disturbance and Climate Variation for the Northern Plains

Location: Livestock and Range Research Laboratory

2022 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. Subobjective 1F: Use precision management technologies (global positioning of livestock, sensor networks, virtual fencing, remote sensing of landscape and others) to enhance livestock producer capability for optimum management of pastures and rangelands, allowing balance between production and ecosystem services. 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.

Progress Report
Objective 1A: Field data collection is complete and laboratory analysis is currently being conducted. Objective 1C: Vegetation samples were collected and growing season grazing treatments and diet samples were completed. Objective 1D: Changes in staff that previously maintained molecular lab equipment necessary for the project and COVID-19 restrictions altered the schedule. Milestones were rewritten to reflect the adapted plan. Amplifying polymerase chain reaction and tagging DNA samples will begin in fiscal year (FY) 2023. DNA amplification and tagging process will complete after the research cycle has ended. Objective 1E: Research was published indicating March calving increased calf growth compared to May calving and warming trends have reduced mortality. Objective 1F: Unassisted aerial vehicles (UAV) were procured, and image acquisition protocols are being developed and tested. A smart supplemental feeder and smart scale were procured, and the smart scale has been installed at the study site. A field spectrometer unit was procured for gathering spectral signatures from vegetation and soils; however, because of supply chain issues, the unit will not be available until 2023. Therefore, planned data collection with the instrument has been delayed. Global Positioning System collars were built, tested, and made ready for planned data collection in Fall 2022. Machine learning algorithms were researched and tested for estimating forage biomass from remote sensing and UAV imagery. Objective 3B: The data were collected and analyzed, and the manuscript is in peer-review. Objective 3C: The year four data were collected, and a decision was made to not continue for a fifth year. The data have been analyzed and the manuscript is being written. Objective 3D: Supporting greenhouse experiments tested fire effects on Russian olive seeds and seedlings. New field plots were established, and seedlings were transplanted. Minor flooding occurred at the site, but seedling survival was 98%. Objective 4A: The final data were collected. Objective 5: A greenhouse experiment was started and completed. Shoot biomass data were collected, and root data are being completed. We prepared mycorrhizal inocula. Soil treatments were established and allowed to incubate for 35 days. In the greenhouse, plants were grown in experimental pots for 105 days. Plant available nutrients were measured in the upper strata of pots. Pots were harvested and shoots were collected, dried, and weighed. Pot contents were frozen, and we are in the process of cleaning, drying, and weighing roots. We have also devised a method for measuring plant available phosphorus with incubations of anion exchange membranes and soil from the sub-strata where carbonate treatments were positioned. Trials will start once all the materials have been received. Other response variables (e.g., shoot phosphorus, mycorrhizal community composition) will be collected by a collaborator this winter. Objective 6A: COVID-19 restrictions prevented the collaborator from growing plants for fire treatments. Plans have been developed to grow the plants in our greenhouse and proceed if the collaborator cannot start plants on the revised schedule. Objective 6B: An additional drought treatment year was added to expand the data range because ambient June precipitation was dry prior years. The wet June needed was received this year, allowing final data collection. Objective 6C: Fire seasonality treatments were applied and final grazing selection trials are being completed.

1. Calving date effects on weaning weight. Calves need more nutrients as they mature. However, because of seasonal growth cycles of rangeland plants, nutrient availability peaks in the spring and then declines through the summer as plants mature. To take advantage of when plant nutrients are more available, producers could time their calving to occur in late winter rather than spring. Calves would then be larger in the spring when rangeland plant nutrients are more plentiful. However, late winter calving has an increased risk of calf death because of greater chances of extreme winter weather. ARS scientists in Miles City, Montana, studied how different calving dates, ranging from early March to early May, affected calf weight gain and winter weather exposure using 82 years of data gathered in the western U.S. They found that, on average, 180-day old calves born in early March weighed 13% more than those born in early May. Early calving also benefited overall herd production with early calves weighing more at 180 days when compared to all calves born each year. These production benefits increased as climate warmed over the study period because the warming reduced the number of calves dying from exposure to cold temperatures. Continued late winter and early spring warming would further increase benefits of early calving.

2. Burn severity impacts of rangeland wildfires. Over the last three decades, large wildfires have increased on rangelands across the western United States. These wildfires have varied in burn severity (defined as the amount of heat directed by the fire to the soil surface), both within and across wildfire locations. Burn severity of a wildfire can impact a rangeland plant’s ability to survive or recover from fire. ARS researchers in Miles City, Montana, collaborating with scientists from Texas A&M University, examined how historical wildfires, with varying burn severity levels, influenced changes in grass, shrub, and tree cover. For the analysis, they used a new plant cover product (Rangeland Analysis Platform - Cover) developed using satellite and field data. Relationships between plant cover and soil moisture conditions before and after the fire were also examined. Researchers found that high severity wildfires led to large decreases in plant cover for all plant types. Higher soil moisture that increased grass cover before fires led to greater decreases in grasses after fires. Drought conditions before fires led to greater decreases in shrub and tree cover. Results of this study will assist land managers in evaluating conditions that could lead to severe wildfires and in weighing management options to reduce wildfire impacts.

3. Carbon ranching. Many companies have started to pay ranchers to change their management on rangelands with the aim of increasing soil carbon storage. However, little is known about which management practice will store a maximum amount of soil carbon for a given location. ARS scientists in Miles City, Montana, reviewed published studies and identified several knowledge gaps. The most critical gap was the need for doing research with preferred methods. Using a study with preferred methods, researchers found that plant material inputs were not the primary driver of soil carbon storage in rangelands. This finding is opposite to the prevailing view. Short-term (5 year) soil carbon storage was mainly linked with decreased carbon outputs and was negatively (not positively) linked with plant material inputs.

4. Grassland soil responses to prescribed fire. Heat produced by wildland fires can penetrate the soil, affecting some soil properties that influence plant growth and soil health positively, and others negatively. However, for the Northern Great Plains, information is lacking on how soil properties such as plant-available nitrogen and soil microbes respond to heat produced by prescribed fires used for rangeland management. ARS researchers in Miles City, Montana, and Sidney, Montana, collaborated with North Dakota State University to measure flame temperatures, soil heating, and response of plant available nitrogen and soil microbes to fire. Although fire temperatures varied widely, heating was limited to the top inch of soil. Plant available nitrogen (nitrate) peaked 7 months after the fire, at the beginning of the next growing season. Soil microbes were unaffected by fire. Land managers throughout the Northern Great Plains can rely on prescribed fire to boost plant-available nitrogen without harming important soil microbes.

5. Grazing effects after large wildfire. Management decisions following wildfire often require a choice between the monetary cost of not grazing and the ecological cost of slowing vegetation recovery by livestock grazing. The Lodgepole Complex fire was the largest U.S. wildfire during 2017, burning 270,194 acres in east-central Montana. This fire provided ARS scientists in Miles City, Montana an opportunity to examine if vegetation recovery after wildfire is slowed by grazing. In ponderosa pine woodland, they tested the effects of moderate grazing and timing of mowing during the first growing season after fire on plant productivity and species composition. The numbers of native and all plant species were greater on grazed sites than nongrazed sites. Current-year and perennial grass production were not affected by mowing. June mowing reduced cool-season grasses and increased warm-season grasses, and June and July mowing each reduced annual grasses. Results indicate the herbaceous plant community in ponderosa pine woodland is resilient to grazing after wildfire.

6. Declining nitrogen availability in land ecosystems. Global supplies of nitrogen have more than doubled in the last century, mainly due to industry and farming activities. However, recent studies show nitrogen has decreased in many areas of the world. ARS researchers in Miles City, Montana, along with scientists in the United States and Europe have examined the causes of decreased nitrogen availability. Nitrogen inputs are not evenly distributed around the world. In many locations, increases in carbon dioxide and warmer temperatures are increasing plant demand for nitrogen. This increased nitrogen use by plants decreases its supply. In areas where nitrogen levels have decreased, plant growth can also be decreased due to lower nitrogen content. These decreases affect both the amount and quality of forage for livestock, wildlife, and insects. Several measures could be used to decrease these declines in nitrogen. Reducing carbon dioxide emissions would lessen the demand for nitrogen by plants. Nitrogen could also be better managed in areas that have experienced nitrogen declines. Strategic feeding of supplements may be required to maintain livestock production in areas with declines. In general, monitoring nitrogen conditions to inform management decisions should be adopted.

7. Perspectives on invasive annual grass management. Invasive annual grasses have spread throughout rangelands in the western United States, impacting the function and productivity of these systems. Multiple land management agencies are working to limit the spread of wildfires in rangelands having large areas of invasive grasses. However, best practices for controlling invasive grasses and a better understanding of interactions between wildfire and annual grass invasions are lacking. Researchers in Miles City, Montana, collaborated with ARS scientists in Sidney, Montana, to research effective control strategies to reduce wildfire spread and document invasive annual grass responses to fire in the Great Plains. Researchers used fire spread models to determine which plant traits contribute to effective greenstrips, which are linear strips of less-flammable species planted in areas having large acreages of invasive grasses. These greenstrips interrupt the spread of wildfire, protecting areas from fire and provide firefighters chances to safely control fires. Researchers have also combined field and satellite data to determine that rangeland fire management in the eastern Great Plains is compatible with objectives to limit the frequency and abundance of invasive annual grasses. ARS researchers have been invited to contribute these “lessons learned” to national efforts describing ARS impacts on knowledge of invasive annual grass management.

Review Publications
Rinella, M.J., Bellows, S.E., Geary, T.W., Waterman, R.C., Vermeire, L.T., Van Emon, M.L., Cook, L.A., Reinhart, K.O. 2022. Early calving benefits livestock production under winter and spring warming. Rangeland Ecology and Management. 81:63-68.
Rinella, M.J., Bellows, S.E., Davy, J.S., Forero, L.C., Hatler, W.L., James, J.J. 2021. Pasture-scale evaluation of postemergence applications of aminopyralid for controlling medusahead (Taeniatherum caput-medusae). Rangeland Ecology and Management. 79(1):201-207.
Reinhart, K.O., Worogo, H., Rinella, M.J. 2021. Ruminating on the science of carbon ranching. Journal of Applied Ecology. 59(3):642-648.
Reinhart, K.O., Worogo, H., Rinella, M.J., Vermeire, L.T. 2021. Livestock increase soil organic carbon in the Northern Great Plains. Rangeland Ecology and Management. 79:22-27.
Mason, R., Elmore, A., Fulweiler, R.W., Groffman, P., Craine, J., Lany, N., Jonard, M., Ollinger, S., Angerer, J.P., Read, Q., Reich, P.B., Templer, P.H. 2022. Evidence, causes, and consequences of a global decline in ecosystem nitrogen availability in terrestrial ecosystems. Science. 376(6590).
McGranahan, D.A., Wonkka, C.L. 2022. Fuel properties of effective greenstrips in simulated cheatgrass fires. Environmental Management. 70:319-328.
Borda, V., Reinhart, K.O., Ortega, M., Burni, M., Urcelay, C. 2022. Roots of invasive woody plants produce more diverse flavonoids than non-invasive taxa, a global analysis. Biological Invasions.
Li, Z., Angerer, J.P., Wu, X. 2022. The impacts of wildfires of different burn severities on vegetation structure across the western United States rangelands. Science of the Total Environment. 845. Article 157214.
Williams, A.R., Vermeire, L.T., Waterman, R.C., Marlow, C.B. 2022. Grazing and defoliation timing effects in Great Plains ponderosa pine woodland following a large summer wildfire. Forest Ecology and Management. 520. Article 120398.
Raynor, E.J., McGranahan, D.A., Miller, J.R., Schacht, W.H., Debinski, D.M., Engle, D.M. 2021. Moderate grazer density stabilizes forage availability more than patch burning in low-stature grassland. Land. 10:395.
McGranahan, D.A., Wonkka, C.L., Rana Dangi, S., Spiess, J.W., Geaumont, B. 2022. Mineral nitrogen and microbial responses to soil heating in burned grassland. Geoderma. 424. Article 116023.
Rinella, M.J. 2022. Low neighbor abundances are often necessary but insufficient for establishing seeded shrubs. Rangeland Ecology and Management. 82:37-41.
Reinhart, K.O., Rinella, M.J., Sanni Worogo, H., Waterman, R.C., Vermeire, L.T. 2022. Lessons from a next generation carbon ranching experiment. Global Change Biology. 425. Article 116061.
Rinella, M.J., Bellows, S.E., Beitz, P.A. 2022. Low rate of aminopyralid nearly eliminates viable seed production in barb goatgrass (Aegilops triuncialis). Invasive Plant Science and Management. 15:57-60.
James, J.J., Brownsey, P., Davy, J., Forero, L., Stackhouse, J., Shapero, M., Becchetti, T., Rinella, M.J. 2022. Management strategies determine how invasive plant impacts on rangeland provisioning services change net revenue on California annual rangeland. Rangeland Ecology and Management. 82:29-36.
Shackelford, N., Paterno, G.B., Winkler, D.E., Porensky, L.M., Boyd, C.S., Clements, T.C., Espeland, E.K., Monaco, T.A., Rinella, M.J., Munson, S.M., Ballenger, E.A., Quiroga, R., Wainwright, C.E., Bahm, M.A., Barger, N., Baughman, O.W., Becker, C., Esteban Lucas-Borja, M., Calleja, E., Caruana, A., Davies, K.W., Deák, B., Drake, J., Dallau, S., Eldridge, J., Farrell, H.L., Fick, S.E., Garbowski, M., de la Riva, E., Golos, P.J., Grey, P.A., Heydenrych, B., Holmes, P.M., James, J.J., Jonas-Bratten, J., Kiss, R., Kramer, A.T., Larson, J.E., Lorite, J., Mayence, C., Merino-Martín, L., Miglécz, T., Montalvo, A.M., Navarro-Cano, J.A., Paschke, M.W., Luis Peri, P., Pokorny, M.L., Saayman, N., Schantz, M.C., Parkhurst, T., Seabloom, E.W., Stuble, K.L., Uselman, S.M., Valkó, O., Veblen, K., Wilson, S., Wong, M., Xu, Z., Suding, K.L., Svejcar, L.N., Erickson, T.E., Leger, E.A., Breed, M.F., Faist, A.M., Harrison, P.A., Curran, M.F., Guo, Q., Kirmer, A., Law, D.J., Mganga, K.Z., Török, P., Abdullahi, A., Carrick, P.J., Burton, C., Burton, P.J. 2021. Drivers of seedling establishment success in dryland restoration efforts. Nature Ecology and Evolution. 5:1283-1290.