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ARS Home » Plains Area » El Reno, Oklahoma » Grazinglands Research Laboratory » Forage and Livestock Production Research » Research » Research Project #424179

Research Project: Integrated Forage Systems for Food and Energy Production in the Southern Great Plains

Location: Forage and Livestock Production Research

2014 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.

Progress Report
The government shutdown and furlough between October 1 and 17, 2013, had a significant detrimental effect on several elements of the project activities and progress during FY14. Time-critical field operations could not be accomplished during the furlough, with the consequence that scheduled planting of experiments was not achieved and milestones dependent on the implementation of these experiments were not met. The delayed start of activities within subobjectives 2A, 2B, and 4A requires that FY14 and subsequent milestones be deferred by 12 months. Data collection to measure impacts of grazing management for tallgrass prairie continued during the reporting period and, in intensive campaigns during the summer, greenhouse gas (GHG) emissions by grazing cattle were monitored. Analysis of emissions data is planned early in FY15. Work on the effects of redcedar or of remediation efforts on soil properties of old fields was not possible as a consequence of staff shortage, and application for post-doctoral assistance was made to mitigate this problem. Greenhouse studies of nitrogen use efficiency in cool-season grasses (2B.1) and of N-fixation and transfer by warm-season legumes (2.B.2) were initiated during the reporting period. These will continue into FY15. Initial carcass data from grazed cattle of different genetic types will be available by early FY15 and study of sensory data on meat quality should be completed by mid-FY15. Lolium sp. hybrids were generated using the inducer technology and were sown to the nursery for selection. Frequency of inducer-based dihaploid (DH) generation in both tall fescue and meadow fescue were calculated. Two tall fescue synthetics (Syn1, Syn1RR) generated by the above approach have had 2nd year of PVP data obtained and the data are under preparation for compiling into the PVP application. The PVP applications will be submitted by the end of the 2014 fiscal year. Marker surveys conducted to identify DH or non-DH status of tall fescue lines derived from the inducer approach were successfully implemented and evaluated. Frequencies of DH generation across pollen parents were identified. Marker data was also successfully applied to identify variation across identified DH lines. Additional generation and identification of a more diverse sample of DH tall fescue lines is required for full genetic distance groupings. Field nursery studies of 100 F1 hybrids have identified variation in DH production, and resistance/tolerance to drought, rust, and soil conditions. A tendency for rhizomatous formation across DH generated from some F1 hybrid crosses (parental germplasm) was also identified. DH generated from these F1 should possess the superior attributes identified in the most successful and vigorous F1 hybrids. Yield results from two preliminary F1 DH derived tall fescue hybrids indicates the potential for heterotic responses across DH lines. Smooth bromegrass (Bromus inermis) lines exhibiting tolerance to glyphosate herbicides were successfully extracted from the original smooth bromegrass population. Intercrossing among these glyphosate-tolerant individuals was generated and transferred to a cooperator for commercial increase and evaluation. Seed of 15 clones of a South American bromegrass (Bromus auleticus) also exhibiting tolerance to glyphosate herbicide applications was increased and was sown in the fall of 2013 for observation and seed increase with a cooperator. Intercrosses were made across 35 superior orchardgrass clones. Seed taken from these clones will be sown to the nursery in fall of 2014 for observation and potential additional seed increase. Seed increase from intercrossing 25 perfect flowered Texas bluegrass clones was transferred to a cooperator for sowing and additional seed increase and initial performance evaluation in Albany, OR, USA. Cp DNA was successfully isolated from fresh leaf tissue of Lolium multiflorum. In addition, utilizing FTA cards impregnated with a leaf sample also provided Cp DNA of a quantity and quality useful for PCR analysis. Preliminary analysis was initiated utilizing ten available Cp based "TEA" markers for inducer cytoplasm characterization.

1. Completed three Plant Variety Protection (PVP) applications for a stress tolerant smooth bromegrass and two endophyte tall fescue cultivars. PVP applications are required prior to OTT licensing of the plant products to commercial entities. A commercial company, Barenbrug Seeds, USA, Albany, OR, has requested exclusive licensing of three materials. Impact: Attainment of PVP allows licensing of these materials to a commercial company which will the produce and market the three new cool-season, perennial grass forage cultivars to the consumer.

2. Publically released an annual cereal rye named (ER-1, Chason) which is suitable for use as a grazing livestock forage in regions that experience excessive drought and low nitrogen conditions or input. Seed was deposited with the National Seed Storage Laboratory and seed was requested and distributed to the USDA-ARS, Great Basin Research Laboratory for evaluation as a drought tolerant, beneficial grass forage cultivar that would be sown to compete and reduce the growth and seed production of invasive grasses such as cheatgrass and medusahead. Impact: The release of this material can provide livestock producers in dry and low nitrogen input environments to produce a nutritious and competitively yielding forage for livestock grazing.

3. Scientists identified a series of annual ryegrass molecular markers that will enhance the ability of researchers to identify a particular class of ryegrass-tall fescue hybrids that previously could only be identified by chromosome counts. Impact: the identification of these molecular markers will allow a more rapid and efficient identification of this unique class of ryegrass-tall fescue hybrids which will in turn, will allow more rapid evaluation and release of high performance ryegrass-tall fescue hybrids as cultivars.

Review Publications
Starks, P.J., Venuto, B.C., Dugas, W.A., Kiniry, J.R. 2014. Measurements of canopy interception and transpiration of openly-grown eastern redcedar in central Oklahoma. Environment and Natural Resources Research. 4(3): DOI: 10.5539/enrr.v4n3p103.