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

Location: Livestock, Forage and Pasture Management Research Unit

2019 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
This is the first report for the new project 3070-21610-003-00D which began in June 2019 and replaces the previous bridging project, 3070-21610-002-00D, “Integrated Forage Systems for Food and Energy Production in the Southern Great Plains” initiated in December 2018; Please see the report for the previous project for additional information. Milestones of the objectives and sub-objectives of the research project 3070-21610-003-00-D for FY 19 have been met or exceeded. An ARS researcher at El Reno, Oklahoma developed germplasms of different introduced and native grass species within sub-objectives 1.A, 1.B, and 1.C, and research within each of these Sub-Objectives are proceeding according to schedules noted in milestones. The various developed genetic stocks, and germplasms, have been transferred to Cooperative Research and Development Agreement (CRADA) 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 in FY 2021. These new plant materials are being develop 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 short-term effects of annual legumes grown as green sources of nitrogen, and how they affected the nitrogen balance of different winter wheat and summer forage agroecosystems in a series of journal papers. Results identified a series of issues that need to be addressed in future research, to improve the transfer of nitrogen (N) 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 extensive, long-term examinations of legumes used as sources of green nitrogen in different production systems in the southern Great Plains, across a wide range of types of growing seasons. A research team of ARS scientists at El Reno, Oklahoma, and 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 cover crops to following forage and grain crops. Research results reported that some commercially-available inhibitors of nitrification failed to prevent loss of nitrogen in the biomass of cover crops to the atmosphere as nitrous oxide, and identified other approaches for consideration. 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. Two new experiments related to these sub-objectives were initiated to define how other grain legumes function as forage, or sources of green nitrogen in agroecosystems. A team of ARS researchers at El Reno, Oklahoma have started new studies as components of Sub-Objective 2.B that will aid in defining how different forage sequences will affect growth by yearling cattle that are entirely, or largely, finished on pasture. This will include the use of forage species, and combinations of species, that allow yearling cattle to remain and grow on pasture after the availability of wheat pasture has ended, or the quality of available forage from perennial grass pastures is too low to support rapid gains by cattle. ARS scientists at El Reno, Oklahoma, in collaboration with researchers at Oklahoma State University continued an experiment in Sub-Objective 3.A that will identify 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. Species, and cultivars within species, from this broad pool were chosen and tested for their potential to function within the climatic extremes that exist in the southern Great Plains, to augment current production systems in the region. Two species of legumes (tepary bean from Central and South America; moth bean from countries bounding the western Indian Ocean) and one cereal grass (finger millet from India) were identified as having the potential for growth in the Southern Plains. The FY19 period was the first year of testing responses to crop management. ARS researchers at El Reno, Oklahoma, collected data during the third 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. A new experiment was also over-laid on this study, as a component of research activities related to the Grazinglands Research Laboratory - Eddy covariance (FLUX) NETwork (GRL-FLUXNET) in Sub-Objectives 4.A and 4.C, to compare differences in carbon, water, and energy fluxes at the soil-plant-animal-atmosphere interface of the assigned annual burn-intensive early stocking treatments by yearlings with; annual burns and early-season hay harvests, and spring burns and rotational grazing by cow herds. ARS researchers at El Reno, Oklahoma, undertook the assignment of eddy covariance (EC) systems in 18 paddocks of different types of annual and perennial pastures, and croplands that were part of the “GRL-FLUXNET’ system as part of meeting Sub-Objective 4.A. Data from the network is being collected and compiled on a continuous, 12-month basis, including pastures of winter wheat, alfalfa, native prairie, Old-World bluestem, and other perennial grasses and annual crops. Under Sub-Objective 4.B, ARS scientists at El Reno, Oklahoma, undertook integration of the first years’ data related to combining remotely-sensed information and EC measurements collected from a range of pasture types, to examine how management decisions interacted with climate variability. Included within activities was the development of a review paper related to EC fluxes in native prairie. A team of ARS scientists at El Reno, Oklahoma, undertook studies under Sub-Objective 4.C, to describe the dynamics that exist in the carbon and water balance of different grassland and cropland systems in response to applied management. Activities included collection and analysis of data from subsets of EC systems that were part of the “GRL-FLUXNET’ system. These efforts resulted in the development of a manuscript defining within year variations in CO2 flux from alfalfa fields under rain fed conditions; papers defining carbon and water balances in other agroecosystems are currently being written. ARS researchers at El Reno, Oklahoma, undertook the collection of regional-scale data related to evapotranspiration and biomass production of native grasslands under Sub-Objective 4.D, as part of the effort to meet first years’ efforts related to this activity. 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. A series of 4 papers were published to examine and explore water and carbon flux in relation to remote sensing, as first steps in completing milestones under Sub-Objective 4.D. Under Sub-Objective 4.E, ARS scientists at El Reno, Oklahoma, undertook studies defined to provide information that will improve water management in the southern Great Plains, by developing tools that separate the two parts of evapotranspiration (evaporation of water from soils; transpiration of water by plants due to photosynthesis). Preliminary tests found that the isotope technique initially outlined in experimental protocols of Sub-Objective 4.E was not suitable for the study design being applied. A more-effective technique was identified as a replacement, and Milestones for this Sub-Objective will be unaffected.

Accomplishments
1. Cultivar registration for “Artillery” smooth bromegrass. The Southern Great Plains present a challenge to producers using introduced perennial cool-season grasses, due to the hot, dry climate. These problems require new plant materials that tolerate the hot and dry summers in the region. An ARS researcher at El Reno, Oklahoma, and collaborators, have registered the recently-developed smooth bromegrass cultivar “Artillery”, for sale in Canada; registration of this cultivar in Europe and Russia are pending. This new cultivar was selected and developed for its capacity to function under hot, dry growing conditions, and on lower amounts of fertilizer than existing cultivars of bromegrass that are available in North America or Europe. Artillery smooth brome will allow producers in a range of hot and/or dry climates worldwide to grow pastures of this high quality grass where smooth bromegrass would not grow in the past.

2. A Plant Variety Protection application for cultivar “Ammo” orchardgrass. The hot, dry climate and variable growing conditions in the Southern Great Plains are challenges to the use of introduced perennial cool-season grasses by producers in the region. Such conditions require new plant materials that tolerate the extremes presented by the hot and dry summers of the region. In response, an ARS scientist at El Reno, Oklahoma, submitted an application for Plant Variety Protection (PVP) for a newly developed cultivar of orchardgrass called “Ammo”. This new orchardgrass cultivar was selected and developed to function in hot and dry conditions, and with small inputs of fertilizer, where existing cultivars of orchardgrass fail. This cultivar will allow producers in the Great Plains to grow pastures of high quality orchardgrass in areas where this species will currently not survive.

Review Publications
Baath, G.S., Northup, B.K., Rocateli, A.C., Gowda, P.H., Neel, J.P. 2018. Forage potential of summer annual grain legumes in the southern Great Plains. Agronomy Journal. 110(6):1-13. https://doi:10.2134/agronj2017.12.0726.
Kandel, T., Gowda, P.H., Northup, B.K., Rocateli, A. 2019. Impacts of tillage systems, nitrogen fertilizer rates and a legume green manure on light interception and yield of winter wheat. Cogent Food & Agriculture. https://doi.org/10.1080/23311932.2019.1580176.
Kandel, T.P., Gowda, P.H., Northup, B.K., Rocateli, A.C. 2019. Incorporation and harvest management of hairy vetch-based green manure influence nitrous oxide emissions. Renewable Agriculture and Food Systems. https://doi.org/10.1017/S174217051900019X.
Baath, G., Northup, B.K., Gowda, P.H., Rocateli, A.C., Turner, K.E. 2018. Adaptability and forage characterization of finger millet accessions in U.S. southern Great Plains. Agronomy Journal. 177:1-9. https://doi:10.3390/agronomy8090177.
Ma, S., Zhou, Y., Gowda, P.H., Dong, J., Zhang, G., Kakani, V., Wagle, P., Chen, L., Flynn, K.C., Jiang, W. 2018. Application of the water-related spectral reflectance indices: a review. Ecological Indicators. 98:68-79. https://doi.org/10.1016/j.ecolind.2018.10.049.
Moorhead, J.E., Marek, G.W., Gowda, P.H., Lin, X., Colaizzi, P.D., Evett, S.R., Kutikoff, S. 2019. Evaluation of evapotranspiration from eddy covariance using large weighing lysimeters. Agronomy. 9(2):99. https://doi.org/10.3390/agronomy9020099.
Northup, B.K., Starks, P.J., Turner, K.E. 2019. Stocking methods and soil macronutrient distributions in southern tallgrass paddocks: Are there linkages? Agronomy. 9(6):281. https://doi.org/10.3390/agronomy9060281.
Northup, B.K., Starks, P.J., Turner, K.E. 2019. Soil macronutrient responses in diverse landscapes of southern tallgrass to two stocking methods. Agronomy. 9(6):329. https://doi.org/10.3390/agronomy9060329.
Kandel, T.P., Gowda, P.H., Northup, B.K., Rocateli, A.C. 2019. Soil respiration from winter wheat-based cropping systems in the US Southern Great Plains as influenced by tillage managements. Acta Agriculturae Scandinavica. https://doi.org/10.1080/09064710.2019.1582691.
Starks, P.J., Steiner, J.L., Neel, J.P., Turner, K.E., Northup, B.K., Gowda, P.H., Brown, M.A. 2019. Assessment of the standardized precipitation and evaporation index (SPEI) as a potential management tool for grasslands. Agronomy. 9(235). https://doi.org/10.3390/agronomy9050235.
Wagle, P., Gowda, P.H., Northup, B.K. 2018. Annual dynamics of carbon dioxide fluxes over a rainfed alfalfa field in the U.S. Southern Great Plains. Agricultural and Forest Meteorology. 265:208-217. https://doi.org/10.1016/j.agrformet.2018.11.022.
Wagle, P., Gowda, P.H. 2018. Tallgrass prairie responses to management practices and disturbances: A review. Agronomy. 8(12):300. https://doi:10.3390/agronomy8120300.
Wagle, P., Gowda, P.H., Northup, B.K. 2019. Dynamics of evapotranspiration over a non-irrigated alfalfa field in the Southern Great Plains of the United States. Agricultural Water Management. 223:105727. https://doi.org/10.1016/j.agwat.2019.105727.
Tadesse, H.K., Moriasi, D.N., Gowda, P.H., Steiner, J.L., Talebizadeh, M., Nelson, A.M., Starks, P.J., Marek, G.W. 2019. Comparison of evapotranspiration simulation performance by APEX model in dryland and irrigated cropping systems. Journal of the American Water Resources Association. https://doi.org/10.1111/1752-1688.12759.
Talebizadeh, M., Moriasi, D.N., Steiner, J.L., Gowda, P.H., Tadesse, H.K., Nelson, A.M., Starks, P.J. 2019. A parallel computation tool for dynamic sensitivity and model performance analysis of APEX: Evapotranspiration modeling. Journal of the American Water Resources Association. https://doi.org/10.1111/1752-1688.12758.
Masasi, B., Taghvaeian, S., Gowda, P.H., Warren, J., Marek, G.W. 2019. Simulating soil water content, evapotranspiration, and yield of variably irrigated grain sorghum using AquaCrop. Journal of the American Water Resources Association. 55(4):976-993. https://doi.org/10.1111/1752-1688.12757.
Wagle, P., Gowda, P.H., Northup, B.K., Starks, P.J., Neel, J.P. 2019. Response of tallgrass prairie to management in the U.S. Southern Great Plains: Site descriptions, management practices, and eddy covariance instrumentation for a long-term experiment. Remote Sensing. 11(17):1988. https://doi.org/10.3390/rs11171988.
Zhou, Y., Gowda, P.H., Wagle, P., Ma, S., Neel, J.P., Kakani, V., Steiner, J.L. 2019. Climate effects on tallgrass prairie responses to continuous and rotational grazing. Agronomy. https://doi.org/10.3390/agronomy9050219.
Ma, S., Zhou, Y., Gowda, P.H., Chen, L., Steiner, J.L., Starks, P.J., Neel, J.P. 2019. Evaluating the impacts of continuous and rotational grazing on tallgrass prairie landscape using high spatial resolution imagery. Agronomy. 9(5):238. https://doi.org/10.3390/agronomy9050238.
Nelson, A.M., Moriasi, D.N., Talebizadeh, M., Tadesse, H.K., Steiner, J.L., Gowda, P.H., Starks, P.J. 2019. Comparing the effects of inputs for NTT and ArcAPEX interfaces on model outputs and simulation performance. Water. 11:554-580. https://doi.org/10.4236/jwarp.2019.115032.
Khand, K., Taghvaeian, S., Gowda, P.H., Paul, G. 2019. A modeling framework for deriving daily time series of evapotranspiration maps using a surface energy balance model. Remote Sensing. 11(5):508. https://doi.org/10.3390/rs11050508.