Location: Southeast Watershed Research
2023 Annual Report
Objectives
Objective 1. Develop diversified rotational cropping systems for an integrated crop-livestock production system that includes mixed cropping, provide year-round vegetative cover, habitat for arthropod natural enemies and pollinators, and mitigate crop metal toxicity and persistence of antimicrobial resistance.
Sub-objective 1.1. Compare G x E x M effects (where G is taken as crop diversity/rotation – not genetic engineering) on crop productivity and soil and forage quality in a small integrated crop-livestock farming system setting of: 1). An aspirational rotational cropping system that includes summer cotton (Gossypium hirsutum L.), peanut (Arachis hypogaea), summer and winter forages, and a winter oil-rich biofuel feedstock cash crop, in a full year companion cropping system with phosphorus need-based broiler litter fertilization, and reduced tillage under irrigated and dryland conditions (ASP); 2). A business as usual rotational cropping system that includes summer cotton-peanut-corn (Zea mays L.) with a winter rye (Secale cereale) cover crop that is chemically killed and allowed to decompose on the soil surface, with nitrogen need-based broiler litter fertilization, and reduced tillage under irrigated and dryland conditions (BAU-1); and 3). A business as usual rotational cropping system that includes summer cotton-peanut-forage with a winter rye cover crop that is hayed as forage, with nitrogen need-based broiler litter fertilization, and reduced tillage under irrigated and dryland conditions (BAU-2).
Sub-objective1.2. Incorporate native wildflowers in margins of fields in Sub-Objective 1.1 and assess effects on enhancing pest arthropod natural enemies and attracting pollinators.
Objective 2. Develop and test management strategies for an integrated crop-livestock production system that incorporates flue gas desulfurized gypsum (FGDG) with broiler litter (BL) in southeastern cropping systems to reduce phosphorus (P), nitrogen (N) and metals loss in runoff, manage subsoil acidity, and reduce persistence of resistance to antimicrobial agents.
Sub-objective 2.1. Compare the effects of FGDG and FGDG + BL on crop yield; P, N, and metals loss in runoff; subsoil acidity; and SOM composition.
Sub-objective 2.2. Compare the persistence of foodborne pathogens and bacteria with resistance to metals and antibiotics in cropping systems.
Objective 3. Evaluate and quantify farm-level economic and ecosystem services benefits and risks associated with the use of broiler litter, flue gas desulfurized gypsum, and field edge arthropod habitat buffers for southeastern crop-livestock production systems.
Sub-objective 3.1. Develop a five-year multi-practice planning scenarios using a cooperator’s farm (Wilson Farm WF) as a case study that compares net sustainable profit from Objective 1 cropping systems given the producer’s profit versus environmental goals.
Sub-objective 3.2. Forecast cropping systems effects on runoff losses of water, sediment, C, N, P, S, and metals.
Sub-objective 3.3. Integrate producer’s production, profit, and environmental goals to develop land use designs that optimize producer-desired outcomes.
Approach
The overall goal of this project plan is to develop an integrated production system that provides increased flexibility for small-farm crop-livestock producers to diversify their production portfolio by enhancing the sustainability of ecosystem services delivered from landscapes owned or rented by their operation. We will implement plot-scale research to calibrate crop, environmental, geospatial, economic and whole-farm planning models to compare the performance potential of three enterprise scenarios over a five-year planning cycle. Project objectives will focus on six core subsystems affecting the sustainability of small Crop-livestock producers (Soils, Crops and Forages, Landscape, Livestock, Water, and Economic Sustainability).
In Objective 1, plot-scale research under irrigated and dryland conditions will compare the performance of an Aspirational (ASP) full-year companion rotational cropping system that includes peanut, cotton, summer and winter forages, and a winter oil-rich biofuel feedstock, versus Business as usual (BAU)-1 summer peanut-cotton-corn rotation and BAU-2 summer peanut-cotton-forage rotation, both with a winter rye cover crop. Fertility management will include P-based (ASP) versus N-based (BAUs) application of Broiler litter (BL) supplemented with inorganic amendments as indicated by soil testing. All plots will be managed under strip-tillage and include field edge native wildflower habitat to enhance pollination and populations of pest arthropod natural enemies. Seasonal soil and plant sampling and analyses will be used for quantifying GxExM effects on productivity, forage and soil quality, and beneficial insect dynamics.
In objective 2, we will modify an existing three-year plot-scale experiment of continuous summer corn and winter rye conventional tillage system that examined BL and Flue gas desulfurization gypsum (FGDG) effects on P, N, carbon (C) and metals loss in runoff, and yield. The BL and FGDG annual application rates will be reduced by two-thirds for three years followed by three years with no BL and FGDG amendments. Soil cores down to 100 cm were collected at the start and are collected at three-year intervals thereafter for detailed analyses of distribution of nutrients, soil acidity, and metals. We will track nutrient dynamics in the soil, runoff, and plants from residual sources of BL and FGDG. We will also investigate factors influencing persistence of antimicrobial resistance and crop metal toxicities.
In objective 3, data acquired under objectives 1 and 2 will be used to compare farm-level economic and ecosystem services benefits and risks associated with the three cropping systems (ASP + 2BAU). Economic and environmental models will be used to synthesize the five- and ten-year outcomes of each cropping system under four weather and two land use scenarios.
All research within SEWRL is conducted as part of the ARS Long Term Agroecosystem Research (LTAR) Project. This NP 216 Project Plan is intended to augment NP 211 Conservation Effects Assessment Project (CEAP) research on crop-livestock production systems and develop an option suitable for inclusion as an LTAR ASP system.
Progress Report
Under Objective 1.1 ARS researchers in Tifton, Georgia, successfully completed the fourth year of fall/winter (2022), and the fifth year of spring (2023) field activities at 48 irrigated and 48 dryland plots at the Belflower Farm. Summer crops and forages are corn, cotton, peanuts, tifleaf3 (millet), and sorghum followed by sunn hemp (double crop). Forages are harvested multiple times simulating foraging by cattle. Winter covers include carinata as an oil crop, a rye/black oat mix cover as a soil builder, and rye that is either hayed (simulating grazing) or chemically killed and left on the soil. Fertilizer rates are determined based on soil test results and the cropping system (BAU-1, BAU-2, ASP-1, and ASP-2). All plots are continuously monitored for soil water content and soil water potential with sensors that are removed before planting then re-installed after planting. Logging equipment (one for paired plots), with modem and solar charged batteries, is used to collect and transmit data to a base station. Regular remote sensing of plots using multispectral sensors flown by uncrewed aerial systems has been initiated. Data have been collected throughout the growing season in 2022 and 2023. Improved non-Brassica weed management and planting protocols for the 2022 - 2023 carinata production season resulted in better stand establishment. Yields were 58%, 70%, and 79% of the 1,500 lb/ac target for the dryland and irrigated small (810 sqft) plots and large (24,300 sqft) frost damage plots, respectively. Yield variability was higher for small plots (8.5 and 12.2%) compared to large plots (1.2%). However, competing winter Brassicas are still a challenge.
Under Objective 1.2 the collaborating researcher responsible for this objective retired in December 2020. A replacement researcher (Entomologist) was recruited in 2021. The native wildflowers that were planted on the borders of the irrigated and dryland plots in April 2022 did not survive the heat and drought and were replanted in the fall. These native wildflowers did not survive weed competition and were replanted in the spring. The flowers were planted 0.5’ apart in plastic mulch in rows and are doing much better than last year. Pollinators and beneficials are being sampled using blue vein traps and sweep netting. Due to the difficulty in obtaining a consistent annual stand of wildflowers and since this objective is funded by a different project (6048-22000-046-000D), we are requesting for this Milestone to be removed from this Project Plan.
In regard to Objective 2.1 ARS researchers in Tifton, Georgia, finalized research activities at micro-plots at Gibbs Farm. The research assesses the impacts of application of flue gas desulfurization gypsum and poultry litter on corn production, soil properties, and nutrient losses from surface runoff. The final summer corn crop was harvested in August 2022. The final runoff samples were collected just prior to the corn harvest and are ready for shipment to the Institute of Food and Agricultural Sciences (IFAS) Analytical Services Laboratory at the University of Florida (UF) for quantification of dissolved and total nutrients. The final set of soil cores was collected in March 2023.
In regard to Objective 2.2 efforts on antimicrobial resistance elements and food-borne pathogens have been discontinued. A manuscript by ARS scientists at Tifton and Athens Georgia, Texas Tech University, and Colorado State University (Management and environmental factors influence the prevalence and abundance of food-borne pathogens and commensal bacteria in peanut hull-based broiler litter) has been published.
Under Objective 3 to protect the collaborating producer’s personal information, we changed the farm site name from Wilson Farm (WF) to Sumner Farm (SF). ARS researchers in Tifton, Georgia, continued to acquire continuous weather data from the weather station at SF. A cooperator agreement allocated a six-acre field for scaled up research on one rotation from Objective 1.1. Winter rye and carinata were planted followed by forage millet and cotton this spring. However, dense radish competition in the carinata resulted in a complete loss of the carinata crop, and the producer’s cattle refuse to graze the millet in preference to the sorghum-sudan planted in adjacent fields.
Accomplishments
1. Broiler house management practices and environmental factors are associated with food-borne pathogens. Scientists from Athens and Tifton, Georgia, demonstrated that the probability of detecting Salmonella in peanut hull litter was associated with the number of flocks raised on the litter and their grow-out period, while detection of Campylobacter was associated with the number of flocks and the litter pH. Results suggest that prevention of these pathogens’ persistence in litter will require management interventions tailored to each pathogen.
2. Potential enhancement of nitrogen use efficiency in warm season grasses. Scientists at Tifton, Georgia, isolated nitrogen-fixing gene sequences from the leaves, roots, and rhizomes of sorghum, perennial sorghum, sorghum x sudangrass, bermudagrass, Johnsongrass, and energycane. The gene sequences were similar to 13 genera of endophytic bacteria of which six genera had not previously been identified in grasses. One of these identified genera, Bradyrhizobium, is a common inoculant used in peanut production. The presence of nitrogen fixing bacteria in warm-season grasses suggests that these bacteria may be fixing nitrogen. Further manipulation of this association may reduce producer costs and the environmental impacts of applying synthetic nitrogen fertilizers.
