Location: Forage and Livestock Production Research2015 Annual Report
The long-term objectives of this project are to develop improved techniques that will enhance ecological function and efficiency of resource use in prairie and pastureland, increase forage productivity, and promote sustainability of livestock production systems in the Southern Great Plains. Specifically, during the next five years we will focus on the following: Objective 1: Enhance productivity and ecological function of native tall-grass prairies by development of management practices, including management-intensive grazing, and restoration strategies to follow invasive brush and tree species removal. Sub-objective 1A: Compare the effects of different systems of intensive grazing on plant communities and soil properties of over-utilized tallgrass ecological sites, and define shifts in responses to applied management regimes. Sub-objective 1B: Determine greenhouse gas emissions from soil, plant, and animal components of diverse grazing systems. Sub-objective 1C: Define the influence of eastern redcedar trees on local soil conditions of abandoned cropland (old fields), and identify restoration practices that enhance conversion of retrogressed old fields to native prairie. Objective 2: Increase sustainability in grazing systems and improve year-round availability of forages for grazing through: improved pasture establishment and persistence, use of multipurpose legume crops, reduced need for purchased inputs in crop and forage production systems, and increased efficiency of water and nitrogen use. Sub-objective 2A: Assess effect of tissue damage on grass growth, development, and persistence characteristics. Sub-objective 2B: Identify forage species and management practices, including use of legume crops for green manure, that promote efficiency of resource use, especially N and water use, to increase year-round availability of forage for grazing. Objective 3: Increase marketing options, including providing high-quality farm-finished beef, through development of management systems that optimize on-farm feed resources and minimize the need for external inputs. Sub-objective 3A: Identify and evaluate forage resources for efficacy at critical times in the production cycle for farm-finished beef of different genetic types. Objective 4: Provide decision-support tools to aid land managers in evaluating climatic risks and ecologic and economic outcomes in selecting production and conservation practices and strategies for grazingland ecosystems. Objective 5: Develop improved cool-season grasses and legumes to improve productivity and sustainability of grazing and crop lands in the Southern Great Plains. Sub-objective 5A: Develop tools to support selection of improved cultivars. Sub-objective 5B: Identify germplasm of perennial cool-season grass forages adapted to heat, drought, and nutrient stresses of the Southern Great Plains.
Livestock production systems in the Southern Great Plains are confronted with problems of limited and uncertain forage supply, increased climatic variability, and environmental degradation that threaten economic viability and system sustainability. This project will develop management practices and identify forage genotypes that are resilient under variable climate and will increase forage productivity and input use-efficiency on livestock farms at a range of scales. Commensurate with the scope of the location as a Long-Term Agroecosystem Research network site, we will initiate assessments of greenhouse gas (GHG) emissions and agricultural production under different livestock systems of the Southern Great Plains, including both native prairie and wheat pasture. Data from this study will be pooled with results from similar flux studies in the region to evaluate climate and environmental impacts on system response. To evaluate system resilience, over-utilized prairie ecological sites with a mix of native and introduced species indicative of good and poor condition mixed grass prairie will be used to evaluate the use of infrequent, high-intensity grazing on succession and diversity of forage species at the sites. The impact of prior encroachment of redcedar on old-field nutrient and seedbank reserves and consequent recovery of understory and grass species following removal of redcedar will be assessed. The use of legumes and grasses as green manure sources will be researched for summer (sorghum) and winter (wheat) grain crops to promote efficiency of N and water use. Nitrogen turnover and utilization by the subsequent crop will be assessed. Also, N-uptake and efficiency of utilization of cool-season annual and perennial species will be measured in greenhouse experiments to develop screening methods for plant germplasm. Improved management methods will be developed to fully utilize the genetic potential of new cultivars by enhancing establishment, yields, and utilization by livestock. To increase marketing options of livestock producers, we will determine appropriate forage resources for production of farm-finished beef, either on all forage or with limited grain inputs. Interactions of animal genetic type (frame score) and finishing system (forage or grain) will be assessed. Time-series data from ryegrass trials in four southern states in the last decade will serve as the basis for examining the possible importance of 5-day and 7-day summary weather statistics of the near-surface environment, and the variations of those statistics around decade-long averages, as a predictor for seasonal production. Plant breeding technologies will be used to develop improved cultivars of perennial C3 grasses, particularly fescue, that are more persistent under the regional climatic conditions, and are more water-use efficient. Basic molecular biology and biochemistry/physiology information will be developed that will improve plant breeding techniques and products.
Research scientist staffing through the reporting period was approximately 3.65 SY, or 60%, of the 6.0 SY anticipated in the project plan and, in consequence, progress in some components of the project has been significantly hindered during FY15. In those areas where staffing was adequate, implementation of the project proceeded largely as planned. A series of factsheets describing results of completed and ongoing forage and livestock production research carried out under this project and its immediate predecessors, has been prepared for presentation at the October 2015 Grazinglands Research Laboratory (GRL) Field Day. As part of a broader study of greenhouse gas emissions from grazing systems (1B.), enteric methane production has been measured in a cow herd grazing native pasture. Approximately 1 full year of enteric methane production by the cow herd has been collected. Another intensive campaign collection is planned for Fall 2015. An initial phase of study of the effects of trampling damage on regeneration and growth of tall fescue was completed during the reporting period (2A.) and analysis of results is in process. Greenhouse studies of nitrogen use efficiency in cool-season grasses (2B.1) were conducted during the reporting period and reports on preliminary findings are in preparation. A field experiment investigating the value of fall or spring sown legumes as green manure for warm-season grass (2B.4) was established in fall of 2014 (delayed by one year because the critical planting period was missed during October 2013 government shut-down). Establishment of cow herds to support of the farm-finished beef program (3A.) continued during the reporting period. Calves produced during 2014 are currently on finishing treatments and carcass data will be collected over the coming months. Results from FY 2014 (calves produced in 2013) were presented at the 2015 Reciprocal Meat Conference, Lincoln, NE. An experiment was initiated to evaluate the impact of early season grazing of burned native pasture on stocker and pasture productivity. Initial selection of F1 adapted to low nitrogen and environmental stresses (5A.1.) was completed and 30 surviving F1 that exhibited superior phenotypes were removed from low N plots that had undergone three years of environmental stress at Woodward, OK; Parsons, KS and El Reno, OK. These materials were transferred to the greenhouse to be intercrossed for the development of a low N usage population having adaptation to the environmental extremes of the Southern Plains. Approximately fifty chloroplast molecular markers were evaluated across the Lolium multiflorum inducer lines (IL) and 40 inducer derived lines to characterize the specificity of the inducer lines particular cytoplasmic genotype (Cp characterization, 5A.2). Two molecular markers were identified to be specific to the IL lines and deemed appropriate for identifying any dihaploid recoveries generated through the “inducer approach”. Forage quality estimates of the orchardgrass and smooth bromegrass germplasm were completed and found to be competitive to commercial checks (5B). The smooth bromegrass was released and licensed to a commercial stakeholder for seed production and marketing.
1. Release of ‘Arsenal’ smooth bromegrass. Adapted and tolerant cool-season, perennial grass forages are required in the Southern Plains Region of the U.S. to fill spring and fall forage deficits for grazing livestock. ARS researchers at the Grazinglands Research Laboratory, El Reno, OK obtained plant variety protection and a license for the commercialization and marketing of the smooth bromegrass cultivar in 2016. The release of this cultivar fills a need for cool-season, perennial grass forage germplasm for grazing under low nitrogen, dryland conditions.
2. Patent application for a “Lolium multiflorum line that Induces Genome Loss”. A lack of adapted and tolerant cool-season, perennial grass forages is required in the Southern Plains Region of the USA to fill spring and fall forage deficits for grazing livestock. ARS researchers at the Grazinglands Research Laboratory, El Reno, OK developed a novel approach for generating superior genotypes of tall fescue and its related species utilizing a novel ryegrass. The research resulted in the submission of the third of three U.S., Australian, and EU patent applications for the technology. The release of the materials and patent provide a new and efficient approach for the superior breeding of adapted fescue germplasm.
Bartholomew, P.W. 2014. Self-seeding warm-season legumes for low-input forage production in the southern Great Plains of the USA. Agricultural Sciences. http://dx.doi.org/10.4236/as.2014.512121.
Bartholomew, P.W. 2014. Effect of varying temperature regime on phyllochron in four warm-season pasture grasses. Agricultural Sciences. http://dx.doi.org/10.4236/as.2014.511108.
Kindiger, B.K. 2015. Frequency of androgenesis in poa arachnifera x p. ligularis and p. poiformis hybridizations. Grassland Science. doi:10.1111/grs.12090.
Neel, J.P., Felton, E.E., Singh, S., Sexstone, A.J., Belesky, D.P. 2015. Open pasture, silvopasture, and sward herbage maturity effects on nutritive value and fermentation characteristics of cool-season pasture. Grass and Forage Science. doi: 10.1111/gfs.12172.
Bartholomew, P.W. 2015. Timing of nitrogen fertilizer application for annual ryegrass overseeded into unimproved perennial warm-season pasture. Crop, Forage, & Turfgrass Management. doi:10.2134/cftm2013.0018.
Bartholomew, P.W. 2015. Nitrogen application for spring growth of cool-season grasses overseeded into unimproved warm-season pasture. Crop, Forage and Turfgrass Management. doi: 10.2134/cftm2014.0105.
Northup, B.K., Rao, S.C. 2015. Green manure and forage potential of lablab in the U.S. southern plains. Agronomy Journal. 107(3):1113-1118.
Northup, B.K., Rao, S.C. 2015. Green manures in continuous wheat systems affect grain yield and nitrogen content. Agronomy Journal. 107(5):1666-1672.