Location: Forage and Livestock Production Research2012 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:
A perfect-flowered Texas bluegrass population was released. A line that stimulates di-haploid production 'ILI' was released publicly to the ATCC and as a genetic stock release (Pi660129). Generation of a perfect Poa arachnifera population has been transferred to a commercial cooperator through cooperative research agreement for seed increase and evaluation. Approximately 300 di-haploid lines were obtained from other inducer methodology. Drought conditions during FY11 eliminated all pastures of experimental lines of tall fescue, which terminated studies applied to fescue pastures. Continued drought conditions through FY12 limited applied grazing to tall wheatgrass pastures through FY 12. We terminated field phase of experiments that grazed pastures of tall wheatgrass with stocker cattle at high intensities for 35- to 40-day periods. Data collected from wheat and perennial cool-season pastures were used to develop manuscripts reporting; agricultural and economic function of cool-season grasses in forage and biomass feedstock production systems, and influences of short-term (< 5 years) management on soil properties. In a study on water use by 5 summer grain legumes (pigeon pea, guar, cowpea, mung bean, soybean), mung bean, cowpea, and guar generated lower water deficits in 3 of 4 years, utilized less soil water in 2 of 4 growing seasons. Water use by pigeon pea under grazed and un-grazed conditions was completed and manuscript prepared. Bush-type pigeon pea seed with greater leaf/stem ratio was obtained from ICRISAT for evaluation. Due to its growing season, seed was sent to University of Puerto Rico for seed multiplication. Grass pea lines developed by ICARDA were evaluated along with well adapted AC-Greenfix. AC-Greenfix produced more leaf and stem biomass compared to Mediterranean lines. Data generated by pastures of native prairie, wheat, and introduced cool- and warm-season grasses were reported in manuscripts on the function of near infrared reflectance spectroscopy in predicting soil chemical properties, soil carbon mass, and soil bulk density. Completed field-phase of study on the function of combinations of annual cereal and forage grasses, with and without annual legumes, and grazing of forage combinations with yearling stocker cattle. Annual cool-season mixes of rye, wheat, ryegrass, with and without red clover, supported growth by yearling cattle continually from November to May, roughly 30 days longer than traditional wheat pasture under the drought conditions that prevailed during FY11-12. Pastures of annual sorghum-sudangrass, grown alone and in combination with 2 forage legumes, were adversely affected by the long-term drought during FY 11-12, which reduced forage production during mid to late summer, and led to 50% reduction in applied stocking rates during FY12. Pigeon pea forage has the potential to provide high quality forage to support stocker growth when other forages are overly mature or not available. Average daily gain of 2 lbs/day by stocker cattle grazing pigeon pea were recorded during late August-October, compared to grazing warm-season grasses (1-1.5 lb).
1. Grass forage molecular marker development. Due to the high cost and time-cosuming nature of developing genetic markers, this technology for non–food grasses has lagged behind that for food crops such as wheat, corn, rice, and sorghum. If such molecular markers were available, they could have a direct and immediate application in grass forage studies similar to those applications used in advancing breeding improvements in human-food-based cereal grass species. Scientists at the ARS Grazinglands Research Laboratory in El Reno, Oklahoma, the Japanese Grassland Seed Association, and Barenburg Seeds, USA, developed molecular markers for species of bluegrass that could provide a multitude of breeding and selection enhancements for bluegrass forage and turf. The research resulted in 46 new molecular markers that have wide utility across a variety of bluegrass species. The availability of these markers will allow for DNA fingerprinting, cultivar identification, and marker-assisted selection studies. The results of this study will be of value to other researchers working with bluegrass.