Location: Forage and Livestock Production Research2013 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:
This is the final report for project 6218-21410-003-00D which ended in December 2012 and was replaced by 6218-21610-001-00D under NP-215. No new experiments were initiated under this project, so accomplishments and outreach activities are reported in that project. Substantial progress was made in providing forage resources to complement the traditional wheat pasture system of the southern Great Plains by filling existing forage quantity or quality gaps. We developed and applied a new breeding approach to species of the Lolium genus (tall fescue, ryegrass). This "inducer methodology”"allows development of dihaploid lines (genetically equivalent to homozygous or inbred lines) with the possibility of developing true F1 hybrids comparable to accomplishments in the hybrid corn industry, or hybrid synthetics that capitalize on hybrid vigor. A patent on the technology has been granted in NZ and has been applied for in South America, EU, and USA. Two tall fescue synthetics have been developed and will be licensed and released. Over 300 Poa molecular markers were generated, characterized to be informative across 8 diverse species, and disseminated to commercial genotyping services. Molecular marker analysis confirmed that only genomes equivalent to the male parent were utilized in hybridizations, and offers a new approach for developing new, diverse Poa breeding resources. While perennial cool-season grasses (PCSG) were less effective than winter wheat at meeting strategic forage needs of yearling stocker cattle at the start of fall and spring grazing periods, they generated positive economic returns similar to wheat. Winter wheat forage contained potentially toxic nitrate concentrations in 2 out of 4 years, whereas PCSG forages did not. These results show that producers could use PCSG in wheat-based systems to provide economically viable, animal-safe forage to augment wheat pasture and help support the 1.1 million stockers that annually graze in Oklahoma. Long-term grazing data collected at the Laboratory with wheat and PCSG were used to develop agricultural management functions and economic analyses for beef and biomass feedstock production systems. We evaluated warm- (pigeon pea, guar, forage soybean, cowpea, mung bean) and cool-season (grass pea, lentil) grain legumes as high-quality forage and N source for subsequent crops. Warm-season legumes produced high quality forage and grain when double-cropped during the summer fallow period of wheat, but utilized soil water that was needed for subsequent wheat crops. Management intensity increased soil compaction in the top 6 inches of soil in <3 years, while management sustained for 26 years on native prairie and wheat pasture affected distributions of soil physical properties, with greater compaction under more intensive management. Remotely sensed spectral data were collected and added to a growing database to design and test a generalized equation to predict forage nutritive value of warm- and cool-season grasses and alfalfa. Near-infrared reflectance spectroscopy provided accurate estimates of carbon, nitrogen and organic matter in soils from a range of pasture types and management regimes.
Fisher, M.L., Torn, M.S., Billesbach, D.P., Doyle, G., Northup, B.K., Biraud, S.C. 2012. Carbon, water, and heat flux responses to experimental burning and drought in a tallgrass prairie. Agricultural and Forest Meteorology. 166-167:169-174. DOI:10.1016/j.agrformet.2012.07.011.