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

Location: Livestock, Forage and Pasture Management Research Unit

2020 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
An ARS researcher at El Reno, Oklahoma, has continued developing germplasms of different introduced and native grass species. Within Sub-Objective 1.A, fifty new inducer x meadow fescue and tall fescue lines were generated, and fiscal year (FY) 2020 evaluation for F1 derived dihaploid lines produced 35 new lines of tall fescue; one patent application was submitted for techniques developed in the study. In Sub-Objective 1.B, 18 first generation tentative perennial inducers were transplanted to the cooperator’s nursery for agronomic evaluation, and evaluation for male sterility. In Sub-Objective 1.C, 9 additional eastern gamagrass hybrids were generated. The various developed genetic stocks and germplasms, within the different sub-objectives have been transferred to cooperators for agronomic and performance evaluations. There are additional genetic materials under each sub-objective that remain in development, and are scheduled for release to cooperators through FY 2021. These new plant materials are being developed to provide agricultural producers with perennial forages capable of being productive in drought-affected areas, and under low levels of fertilization. A team of ARS researchers at El Reno, Oklahoma, in collaboration with scientists at Oklahoma State University, undertook a series of experiments within longer-term studies that make up Sub-Objectives 2.A.1, and 2.A.2. They reported effects of annual legumes grown as green sources of nitrogen and inorganic fertilizers on winter wheat systems, and how they affected the nitrogen balance of agroecosystems. Results identified a series of issues that need to be addressed in future research to improve the transfer of nitrogen in legume biomass to following cash crops. The data collection within the longer-term experiments of Objective 2.A added more information to the existing pools that will allow examination of long-term use of legumes as green sources of nitrogen in different production systems in the southern Great Plains, across a wide range of types of growing seasons. Based on results of studies in Sub-Objectives 2.A.1, and 2.A.2, ARS researchers collaborated with scientists at the Oklahoma State University, Stillwater, Oklahoma, and Kansas State University, Manhattan, Kansas, and have started a new series of experiments to test a broader range of wheat-warm season crop and green manure rotations. A research team of ARS scientists aalong with collaborators at Oklahoma State University, undertook a series of experiments under Objectives 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. Research results reported on nitrous oxide emissions from green nitrogen crops and inorganic fertilizers, and the influence of soil moisture on carbon dioxide and nitrous oxide emissions. Research efforts undertaken under Sub-Objectives 2.A.1 through 2.A.3 have resulted in elements of planned activities within all three sub-objectives being one year ahead of schedule, with Sub-Objective 2.A.3 being completed. New experiments related to these sub-objectives were initiated to define how other grain legumes function as forage, or sources of green nitrogen in wheat-based agroecosystems. Studies have continued on 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, that may allow grazing after wheat pasture is no longer available, or the quality of available forage from perennial grass pastures is too low to support rapid gains. AgriLife at Amarillo, Texas, studied the effects of maturity and fertilization on the quality of Old World bluestem feedstocks, and how such factors affected methane production by cattle consuming such forages. ARS scientists, in collaboration with researchers at Oklahoma State University continued an experiment in Sub-Objective 3.A that identified grain-type species of legumes and grasses, from among the 7000 less commonly-grown species used to feed humans worldwide, that might be potentially useful as new forage or grain crops, or sources of green nitrogen, in the southern Great Plains. Research showed the function of three species of grain legumes as forage sources, and on how effectively the combination of near infrared reflectance spectroscopy and machine learning predicted forage quality. They also reported on testing of three species of legumes (tepary bean from Central and South America; moth bean from countries bounding the western Indian Ocean; guar from India and Africa) for their performance under different temperature and moisture regimes, as the first steps towards computer modelling to define responses to the broad range of climate within the southern Great Plains. Researchers collected data during the fourth 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. An additional experiment showed that carbon, water, and energy fluxes at the soil-plant-animal-atmosphere interface in pastures of native prairie that were annually burned and intensively grazed. Researchers undertook the assignment of eddy covariance (EC) systems to 18 different types of annual and perennial pastures, and croplands, that were part of the Grazinglands Research Laboratory - EC (FLUX) NETwork (GRL-FLUXNET) system as part of Sub-Objective 4.A. Data from pastures of winter wheat, alfalfa, native prairie, and other perennial and annual forage and grain crops within the network are being collected and compiled on a continuous, 12-month basis to develop a database. Under Sub-Objective 4.B, ARS scientists undertook integration of data collected from remotely sensed observations and EC measurements of carbon, water and energy fluxes from pastures under different systems of management, to investigate interactions with climate variability. Studies were performed under Sub-Objective 4.C, to describe the dynamics of carbon and water balance in different grassland and cropland systems in response to applied management from data collected by subsets of EC systems within the “GRL-FLUXNET’ system. These efforts resulted in the development of: 1) research defining within year variation in carbon dioxide flux from alfalfa fields under rain fed conditions, 2) research comparing carbon and water balance in winter wheat and canola pastures, and 3) reseaerch defining carbon and water flux in a Johnsongrass pasture managed for hay production. ARS researchers 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. Under Sub-Objective 4.E, we undertook studies to provide information to improve water management in the southern Great Plains by developing tools that separate evaporation from soils from transpiration by plants. Research showed the partitioning of evapotranspiration of rainfed alfalfa into evaporation and transpiration by applying a flux variance similarity-based technique to high frequency eddy covariance data.

Accomplishments
1. Testing water and nutrient efficiencies of crop rotations in rain fed agriculture of the southern plains. ARS researchers at El Reno, Oklahoma, in collaboration with scientists at Oklahoma State University, Stillwater, Oklahoma, and Kansas State University, Manhattan, Kansas, began a series of 4-year experiments at multiple locations across Kansas and Oklahoma. This collaboration will test the function of a range of wheat-based crop rotations. These studies examine different combinations of 3 types and sources of nitrogen, and 9 crop rotations, to identify systems that are efficient in use of both water and nutrients in production of hay and grain crops, without negatively affecting winter wheat. The 19 treatment combinations tested in the experiment will be used to identify effective rotations that improve diversification of agricultural production and improve economic well-being of producers in the Southern Plains, without negatively affecting soil condition and the environment.

Review Publications
Baath, G.S., Baath, H.K., Gowda, P.H., Thomas, J.P., Northup, B.K., Rao, S., Singh, H. 2020. Predicting forage quality of warm-season legumes by Near Infrared Spectroscopy coupled with machine learning techniques. Sensors. 20(3):867. https://doi.org/10.3390/s20030867.
Singh, H., Northup, B.K., Baath, G., Gowda, P.H., Kakani, V.G. 2019. Greenhouse mitigation strategies for agronomic and grazing lands of the US Southern Great Plains. Mitigation and Adaptation Strategies for Global Change. https://doi.org/10.1007/s11027-019-09894-1.
Wagle, P., Skaggs, T.H., Gowda, P.H., Northup, B.K., Neel, J.P. 2020. Flux variance similarity-based partitioning of evapotranspiration over a rainfed alfalfa field using high frequency eddy covariance data. Agricultural and Forest Meteorology. Vol. 285-286. https://doi.org/10.1016/j.agrformet.2020.107907.
Flynn, C.K., Zhou, Y., Gowda, P.H., Moffet, C., Wagle, P., Kakani, V.G. 2019. Burning and climate interactions determine impacts of grazing on tallgrass prairie systems. Rangeland Ecology and Management. 73(1):104-118. https://doi.org/10.1016/j.rama.2019.10.002.
Witt, T.W., Ulloa, M., Schwartz, R.C., Ritchie, G.L. 2020. Response to deficit irrigation of morphological, yield and fiber quality traits of upland (Gossypium hirsutum L.) and Pima (G. barbadense L.) cotton in the Texas High Plains. Field Crops Research. 249:107759. https://doi.org/10.1016/j.fcr.2020.107759.
Wagle, P., Gowda, P.H., Neel, J.P., Northup, B.K., Zhou, Y. 2020. Integrating eddy fluxes and remote sensing products in a rotational grazing native tallgrass prairie pasture. Science of the Total Environment. 712:136407. https://doi.org/10.1016/j.scitotenv.2019.136407.
Kindiger, B.K., Moyer, J. 2020. A dihaploid approach for the selection of forage quality in tall fescue (Festuca arundinacea Schreb). Journal of Plant Breeding and Genetics. 7(3):125-133. https://doi.org/10.33687/pbg.007.03.3013
Wagle, P., Gowda, P.H., Billesbach, D., Northup, B.K., Torn, M., Neel, J.P., Biraud, S. 2020. Dynamics of CO2 and H2O fluxes in Johnson grass in the U.S. Southern Great Plains. Science of the Total Environment. 739:140077. https://doi.org/10.1016/j.scitotenv.2020.140077.
Nelson, A.M., Moriasi, D.N., Fortuna, A., Steiner, J.L., Starks, P.J., Northup, B.K., Garbrecht, J.D. 2020. Runoff water quantity and quality data from native tallgrass prairie and crop-livestock systems in Oklahoma between 1977 and 1999. Journal of Environmental Quality. https://doi.org/10.1002/jeq2.20075.
Baath, G.S., Kakani, V.G., Gowda, P.H., Rocateli, A.C., Northup, B.K., Singh, H., Katta, J.R. 2019. Guar responses to temperature: Estimation of cardinal temperatures and photosynthetic parameters. Industrial Crops and Products. https://doi.org/10.1016/j.indcrop.2019.111940.
Singh, H., Kandel, T.P., Gowda, P.H., Somenahally, A., Northup, B.K., Kakani, V.G. 2019. Influence of contrasting soil moisture conditions on carbon dioxide and nitrous oxide emissions from terminated green manures. Agrosystems, Geosciences & Environment. 2(1):190012. https://doi.org/10.2134/age2019.03.0012
Wagle, P., Gowda, P.H., Manjunatha, P., Northup, B.K., Rocateli, A., Taghvaeian, S. 2019. Carbon and water dynamics in co-located winter wheat and canola fields in the U.S. Southern Great Plains. Agricultural and Forest Meteorology. 279:107714. https://doi.org/10.1016/j.agrformet.2019.107714.
Steiner, J.L., Starks, P.J., Neel, J.P., Northup, B.K., Turner, K.E., Gowda, P.H., Coleman, S., Brown, M.A. 2019. Managing tallgrass prairies for productivity and ecological function: A long-term grazing experiment in the Southern Great Plains, USA. Agronomy. 9(11):699. https://doi.org/10.3390/agronomy9110699.
Kandel, T.P., Gowda, P.H., Northup, B.K., Rocateli, A.C. 2019. Winter wheat yield and nitrous oxide emissions in response to cowpea-based green manure and nitrogen fertilization. Experimental Agriculture. 56(2):239-254. https://doi.org/10.1017/S0014479719000334.
Baath, G.S., Northup, B.K., Gowda, P.H., Rocateli, A.C., Singh, H. 2020. Summer forage capabilities of tepary bean and guar in the southern Great Plains. Agronomy Journal. 112(4):2879-2890. https://doi.org/10.1002/agj2.20220.
Kandel, T.P., Gowda, P.H., Northup, B.K. 2020. Influence of tillage systems, and forms and rates of nitrogen fertilizers on CO2 and N2O fluxes from winter wheat cultivation in Oklahoma. Agronomy. 10(3):320. https://doi.org/10.3390/agronomy10030320.