Project : USDA ARS

ARS Home » Plains Area » El Reno, Oklahoma » Oklahoma and Central Plains Agricultural Research Center » Livestock, Forage and Pasture Management Research Unit » Research » Research Project #436466

Research Project: Integrated Agroecosystem Research to Enhance Forage and Food Production in the Southern Great Plains

Location: Livestock, Forage and Pasture Management Research Unit

2023 Annual Report

Objectives
1. Evaluate plant through micro-patch scale responses of new and existing lines of forage species for enhanced climate resilience and positive responses to management. • Sub-objective 1.A: Evaluate frequency and level of dihaploid production in meadow fescue, creeping fescue, and Festuloliums. • Sub-objective 1.B: Generate and evaluate a perennial Lolium inducer line with the ability to produce dihaploids. • Sub-objective 1.C: Generate and evaluate apomictic, hexaploid F1 hybrid eastern gamagrass (Tripsacum dactyloides) germplasm. 2. Define responses of patch-scale attributes at the soil-plant-animal interface to environment and management to improve nutrient-use and production efficiency in forages and animals. • Sub-objective 2.A: Define the longer-term capacity of annual cool- and warm-season legumes as sources of green nitrogen (N) for production of cool- and warm-season forages. • Sub-objective 2.B: Identify and evaluate forage resources for efficacy at critical times in the production cycle of farm-finished beef, and their relationships with frame score, calf growth rate, carcass quality, and economic returns. 3. Examine paddock-scale responses of the soil-plant-animal complex in response to applied management using multi-scale data to assess the potential of diverse ranges of forage and grain crops for function as multi-use crops. • Sub-objective 3.A: Measure responses, and model, novel warm-season annual pulses for their use in grazing and cropping agroecosystems of the SGP. • Sub-objective 3.B: Define carbon (C), N, and microbial fluxes in row crop, wheat-based, and native agroecosystems under different forms of management: green manures, fertilizer inputs, prescribed fire, and grazing. 4. Measure and model landscape-scale responses of soil-plant-animal-atmosphere complexes to identify improved and innovative management strategies that enhance ecological function of grazing lands and increase resilience of production systems. • Sub-Objective 4.A: Establish a network of integrated flux measurement systems (“GRL-FLUXNET”. • Sub-objective 4.B: Characterize the impacts of climate variability and management on different forages at local and regional scales in the SGP. • Sub-objective 4.C: Quantify dynamics of C and water (H2O) balances of native prairie, tame pastures and croplands in response to management practices and biophysical factors. • Sub-objective 4.D: Upscale paddock-level fluxes of C and H2O to regional scales using remote sensing approaches. • Sub-objective 4.E: Improve water management practices and water productivity by reducing non-productive water loss.

Approach
Limited and uncertain forage supply, increased climatic variability, and environmental degradation impact livestock and crop production systems in the Southern Great Plains (SGP) and threaten agroecosystem viability and sustainability. This project will develop management practices and identify crop and forage genotypes that are resilient under variable climate and will increase forage productivity and resource use-efficiency on mixed-agriculture farms across a range of scales. Increased forage productivity from native prairie and tame pasturelands will be achieved through use of practices that enhance ecological condition of grazing lands and minimize or reverse on-farm and downstream environmental damage. New decision-support tools will assist producers in timing and choice of management practices that maximize resource use efficiency under variable climatic conditions. Improved resource use efficiency will reduce unit cost of forage and crop production, and contribute to sustainability of forage-based livestock production. Enhancement of on-farm capacity for forage production is important because increased forage supplies can substitute for feed resources lost to competing enterprises such as grain crops and bioenergy production. Forage-based livestock production that uses improved management practices to enhance ecological function of prairie and pastureland will increase resilience of production systems, increase food security, add value to farming operations, and mitigate greenhouse gas emissions. The end-result will be improved efficiencies of beef production with less grain and fossil fuel inputs, less need for capital through increased use of on-farm products, and increased competitiveness and profitability for producers. To accomplish this goal, understanding interactions between different factors of the soil-plant-animal-atmosphere interface is required to match input resources to desired useful products and ecological benefits.

Progress Report
Most milestones of the bjectives and sub-objectives of the research project 3070-21610-003-00D for FY 23 have been met or exceeded; the primary exception was research under Objective 1. An ARS researcher at El Reno, Oklahoma, developing germplasms of different introduced and native grass species within sub-objectives 1.A, and 1.B retired during the first quarter of FY23, and research within these Sub-objectives were terminated. An ARS researcher in Sub-objective 1.C. utilized hybrids from earlier crosses to generate hexaploid (6n) F1-hybrid eastern gamagrass capable of producing viable seed and produce plants with predictable and uniform performance. Results of efforts in FY22 failed to produce stable and viable hexaploids, so the research was terminated, and the researcher retired. A team of ARS researchers at El Reno, Oklahoma, in collaboration with scientists at Kansas State University, Texas A&M University, and University of Florida, undertook a series of experiments within longer-term studies that make up Sub-objectives 2.A.1, and 2.A.2. Data from the first 6 years of Sub-objective 2.A.1 were reported in a published paper that describes water storage and use efficiencies in intensive winter wheat – summer green N systems, compared to winter wheat – summer fallow systems. Under Sub-objective 2.A.2, journal papers reported on: the value of short-growing season annual legumes as sources of green N & forage; a tool to describe forage quality of annual legumes; and the effects of harvest management for annual legumes. A team of ARS researchers at El Reno, Oklahoma, in collaboration with scientists at the Oklahoma State University, Stillwater, Oklahoma, and Kansas State University, Manhattan, Kansas, continued a series of experiments that test a range of wheat-warm season crop and green manure rotations within the National Institute of Food and Agriculture. Project ‘Increasing Water Productivity, Nutrient Use Efficiency, and Soil Health in Rainfed Agricultural Systems of Semi-Arid Southern Great Plains’. A research team of ARS scientists at El Reno, Oklahoma, and collaborators at Oklahoma State University, completed a series of experiments under Sub-objective 2.A.3 to test different methods of improving the transfer of nitrogen in green manures and inorganic fertilizers to following forage and grain crops. A book chapter describing sources of greenhouse gases and techniques to reduce emissions was published within this Sub-objective. New experiments related to Sub-objectives 2.A.1 to 2.A.3 (initiated in FY21) to define how other grain legumes function as forage, or sources of green nitrogen in wheat-based agroecosystems were continued. A team of ARS researchers at El Reno, Oklahoma, continued studies as components of Sub-objective 2.B that will aid in defining how different forage sequences affect growth by yearling cattle that are entirely, or largely, finished on pasture. This includes the use of forage species, and combinations of species in mixes as cover crops as sources of quality forage to support rapid gains by yearling cattle. Data on growth responses of different novel legumes continues to be collected by ARS researchers and collaborators at Texas A&M University, Kansas State University, and University of Florida that will be applied to future modelling exercises. ARS researchers at El Reno, Oklahoma, collected data during the fifth year of a long-term experiment in Sub-objective 3.B that will develop databases related to how soils and the plant community of southern tallgrass prairie respond to combinations of annual prescribed spring burns and intensive grazing during the early growing season. Treatments could not be applied in FY23 due to extreme drought conditions that prevented prescribed burns, grazing, and hay production. Comprehensive data was continually added to databases in the Oklahoma and Central Plains Agricultural Research Center - Eddy covariance (FLUX) NETwork (GRL-FLUXNET), on the soil-plant-atmosphere interface of rangeland managed by different techniques. Additional years will be added to the study to capture required responses of plant communities and Eddy fluxes under applied management. ARS researchers at El Reno, Oklahoma, continued to undertake the assignment of eddy covariance (EC) systems to 16 different annual and perennial pastures, and croplands, that were part of the “GRL-FLUXNET’ system as part of meeting Sub-objectives 4.A. ARS scientists continued to add data to comprehensive databases on the soil-plant-atmosphere interface of a series of different agroecosystems that were collected by the Eddy covariance (FLUX) NETwork (GRL-FLUXNET) comprised of 16 Eddy covariance systems. A team of ARS scientists at El Reno, Oklahoma, undertook studies under Sub-objective 4.C, to collect data and report on carbon dioxide (CO2), evapotranspiration, and light and water use efficiencies of a series of annual and perennial pastures and croplands under different forms of crop and land management. ARS researchers at El Reno, Oklahoma, continued the collection of regional-scale data related to evapotranspiration and biomass production of native grasslands under Sub-objective 4.D. This collected data will be used to develop regional-scale maps that will help in understanding how climate affects grassland productivity at multi-state scales. Gross primary production and evapotranspiration have been modelled at the site level, but upscaling efforts to examine these features at the regional level were not possible due to the departure of key university personnel undertaking this task. Under Sub-objective 4.E, ARS scientists at El Reno, Oklahoma, and university collaborators undertook studies to provide information pertaining to the partitioning of water use to define losses by evaporation and uses in transpiration by plants in a series of applied cropping systems.

Accomplishments

U.S. DEPARTMENT OF AGRICULTURE

Livestock, Forage and Pasture Management Research Unit: El Reno, OK