Location: Forage and Livestock Production Research2008 Annual Report
1a. Objectives (from AD-416)
The primary goal is to develop a knowledge base and guidelines that will enable producers in the southern Great Plains to diversify forage-based systems, to enhance flexibility and efficiency, and to reduce economic and environmental risks under variable climate, market and policy conditions. The approach is to develop sustainable systems that integrate a diversity of plant species including forages for livestock, multi-purpose crops, and biomass production. Specific objectives include: Objective 1: Provide perennial grasses to regional livestock producers that are adapted, productive, persistent, exhibit desired agronomic characteristics, and can be included in year-round forage based production systems. • Sub-objective 1.A. Develop and evaluate germplasm resources of perennial cool-season grass forages that exhibit favorable agronomic characteristics and are adapted to the climate of the southern Great Plains. • Sub-objective 1.B. Develop PCR-based molecular markers to assist perennial cool-season grass breeding, with emphasis on bluegrasses. • Sub-objective 1.C. Evaluate smooth bromegrass, wheatgrasses, and tall fescues under intensive, short-duration grazing during spring and fall in near year-long forage production systems. Objective 2: Evaluate quality and anti-quality factors in existing forage based livestock production systems that limit animal performance. • Sub-objective 2.A. Evaluate adapted winter wheat cultivars and breeding lines for variation in concentrations of secondary metabolites that may limit the incidence of frothy bloat, and for accumulation of nitrate that may limit performance of cattle grazing wheat forage. • Sub-objective 2.B. Provide a real-time, remote-sensing based approach for estimating forage quality in the field. Objective 3: Incorporate multipurpose legume and grass forage, grain, and biomass crops into integrated and diversified systems that provide a range of agricultural opportunities. • Sub-objective 3.A. Assess the feasibility of integrating multipurpose forage and grain crops into diversified forage and livestock production systems. • Sub-objective 3.B. Provide the knowledge and guidelines required to integrate biomass/bioenergy crops into agricultural land management systems of the southern Great Plains. • Sub-objective 3.C. Assess amounts of nitrogen contributed to subsequent forage, grain and biomass crops by annual and perennial legumes. Objective 4: Provide the knowledge and guidelines required to implement and manage year-long forage based livestock production systems. • Sub-objective 4.A. Design, install, and evaluate farm-scale, year-long forage production systems that include multiple forage species to fill gaps in spring and fall when high-quality forage is not available. • Sub-objective 4.B. Determine whether fast-growing annual legumes and grasses have potential as gap-filling forages for use in near year-long forage production systems in the southern Great Plains.
1b. Approach (from AD-416)
Germplasm with potential for use in the region will be obtained from a variety of sources and evaluated in the field for adaptation, productivity, forage quality, and other traits. Persistence, productivity, and quality of selected perennial cool-season grasses will be genetically improved through traditional and marker assisted breeding methods and interspecific hybridization. Forage crop sequences, including grass, legumes, and legume/grass mixtures will be evaluated in the field under varying levels of fertilization, grazing pressure, and abiotic stress. Hyperspectral reflectance data will be compared to laboratory analyses and bench top near-infrared spectroscopy as an approach to monitoring in-field forage quality and biomass production. Productive and adapted bioenergy feedstock crops will be identified and efficient feedstock production systems developed. Approaches to incorporate feedstock production into existing forage and livestock production systems will be investigated. All proposed research will be in collaboration with ARS, university and private cooperators where appropriate and mutually beneficial.
3. Progress Report
Progress continues to be made in development and evaluation of cool-season perennial forage species that will fill forage deficit periods in traditional grazing systems of the southern Great Plains. Smooth bromegrass and fescue populations were transferred via a materials transfer agreement (MTA) and cooperative research and development agreement (CRADA #58-3K95-8-1233, Germplasm Enhancement of Tall Fescue) for commercial multi-location performance trials. An invention disclosure related to the development of dihaploid tall fescue from an original ryegrass-fescue (Festulolium) population was submitted to the USDA-OTT. Over 40 dihaploid tall fescue lines were developed utilizing the ryegrass hybridization process, and these materials were transferred to a commercial cooperator for evaluation, selection, and subsequent F1 hybrid generation. A new set of interspecific Poa hybrids were successfully created by crossing P. arachnifera x P. labillardierli, P. poiformis, and P. arida in May 2008. Over a four-year period, crude protein and nitrate levels in fall forage clipped from winter wheat pasture and perennial cool-season grass pastures of tall wheatgrass, smooth bromegrass, and intermediate wheatgrass were compared. In two out of four years, winter wheat forage contained nitrate concentrations that could pose a risk to cattle. In contrast, the level of nitrate in the perennial cool-season forages measured each of the four years did not pose a risk to cattle. Levels of crude protein in the perennial cool-season forages were as much as 37% less than that of wheat, but were still sufficient for growth of stocker calves. The cool-season legume 'grass pea' was shown to be capable of generating useful levels of biomass and biological nitrogen across a range of spring planting dates (March 15 to April 15). This planting date 'flexibility' will enhance the use of grass pea for high-quality forage during June through July, or as a green manure for inclusion in cropping systems of the southern Great Plains. Initiated short-term intensive grazing (in the fall and spring) of non-toxic endophyte-infected tall fescue, to provide an assessment of effects on persistence of the perennial grass stands. Also initiated grazing of combinations of pastures of non-toxic endophyte-infected tall fescues, mixtures of annual cereal grasses and legumes, wheat, and perennial warm-season grasses. A multifaceted research project was initiated to determine the biomass value of eastern redcedar, a highly invasive species on native grassland, and the restoration of these grasslands after its removal. This project will coordinate with grazinglands CEAP research and with NRCS RC&D projects attempting to develop redcedar as an economic biofuel in the southern Great Plains region. Research to make real-time estimates of forage quality is continuing. Remote sensing techniques were developed to quantify crude protein concentration and dry matter digestibility of live standing bermudagrass pastures in real-time, (NP 215; Component - Forage Management; Plant Resources)
1. Cool-season perennial grass and annual winter wheat pasture quality: Wheat is considered excellent forage capable of producing stocker weight gains > 3 lb/day, but wheat can accumulate high levels of nitrate that could pose a health risk to the animals. Over a four-year period we compared the levels of crude protein and nitrate in fall forage clipped from winter wheat pasture and perennial cool-season grass pastures of tall wheatgrass, smooth bromegrass, and intermediate wheatgrass. In two out of four years, winter wheat forage contained nitrate concentrations that could pose a risk to cattle. In contrast, the level of nitrate in the perennial cool-season forages measured each of the four years did not pose a risk to cattle. Levels of crude protein in the perennial cool-season forages were as much as 37% less than that of wheat, but were still sufficient for growth of stocker calves. The nitrate risks that sometimes occurred with wheat would make perennial cool-season grasses a safer choice for pasture that producers may consider beneficial when replacing some of their wheat pastures. (NP 215; Component - Forage Management)
2. New legume helps with high fertilizer costs: Rising costs of inorganic fertilizers has renewed interest in new legumes for cropping systems in the southern Great Plains of USA. Productivity of these legumes depends on determining optimum agronomic management and cultural practices. This study examined how planting dates affect the productivity of the cool-season legume 'grass pea'. Grass pea was capable of generating useful levels of biomass and biological nitrogen across a range of spring planting dates (March 15 to April 15). This planting date 'flexibility' will enhance the use of grass pea for high-quality forage during June through July, or as a green manure for inclusion in cropping systems of the southern Great Plains. (NP 215; Component – Forage Management)
3. Development of Poa Molecular Markers: There are few molecular markers for molecular marker and genotyping analysis in the genus Poa, and the development of such markers would increase the efficiency of Poa breeding. Over 300 Poa molecular markers were generated and characterized to be informative across eight diverse Poa species. Markers were disseminated to commercial genotyping services groups via a public accessible web page. These markers provide the first series of molecular markers available for Poa genotyping and molecular marker mapping studies. (NP 215; Component – Plant Resources)
4. Invention Disclosure - A Ryegrass Line that Induces Androgenesis in Wide Hybrids: Breeding tall fescue has changed little in the past 80 years. The identification of a ryegrass line that allows the formation of dihaploid offspring following hybridization of the two species provides a new and efficient method for generating inbred lines. Over 40 dihaploid tall fescue lines were developed utilizing the ryegrass hybridization process, and these materials were transferred to a commercial cooperator for evaluation, selection, and subsequent F1 hybrid generation. Crosses were generated between selected dihaploids, and the materials will be utilized to evaluate levels of hybrid heterosis and seed production potential. Development of this technology creates a new method for breeding and germplasm selection of ryegrass and tall fescue. (NP 215; Component – Plant Resources)
5. Technology to Assess Forage Quality: Quantifying the diet quality of free-ranging cattle is difficult but necessary in order to more efficiently manage animals and pastures. Scientists at the Grazinglands Research Laboratory in El Reno, Oklahoma have developed remote sensing techniques to quantify crude protein concentration and dry matter digestibility of live standing bermudagrass pastures in real-time. Real-time estimation of forage quality enables timely decisions for adjusting stocking rates, managing pastures, and assessment of when to provide supplements to diets of free-ranging cattle, thereby potentially improving profitability of stocker production systems. The technology could potentially be applied in the hay industry to determine optimal timing for hay cutting. (NP 215; Component - Forage Management)
5. Significant Activities that Support Special Target Populations
Zhao, D., Mackown, C.T., Starks, P.J., Kindiger, B.K. 2008. Interspecies variation of forage nutritive value and nonstructural carbohydrates in perennial cool-season grasses. Agronomy Journal. 100:837-844.