Location: Southeast Watershed Research
2024 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
This is the final report for the project 6048-11130-005-000D which terminated on December 23, 2023, and was bridged by 6048-11130-006-000D pending completion of the NP216 review process for the new plan. The new plan was initiated on April 15, 2024.
Substantial results were realized over the five years of the project. Under Objective 1.1, four integrated cropping system scenarios were developed and implemented in 2019 on 48 irrigated and 48 dryland plots, each 12 ft by 45 ft. The summer crops and forages included corn, cotton, peanuts, tifleaf3 (millet), and sorghum followed by Sunn hemp (double crop). Forages were harvested multiple times to simulate foraging by cattle. Winter covers included carinata as an oil crop, a rye/black oat mix cover as a soil builder, and rye that was either hayed (simulating grazing) or chemically killed and left on the soil. Poultry litter was used as fertilizer and the rates were determined based on soil test results and the cropping system. Beginning in 2019, all plots were continuously monitored for soil water content and soil water potential with sensors and data loggers. The sensors were removed in 2023 due to difficulties with the land management (sensors were removed before planting/harvest and re-installed after planting/harvest) and due to SY critical vacancies in the Unit resulting in the lack of expertise in using this data. Remote sensing data of plots has been collected throughout the growing seasons beginning in 2022. Over these five years, we’ve had difficulties establishing a good stand of carinata using strip tillage in the small plots, weed competition has been intense, and late winter frosts have resulted in considerable crop damage. After improving weed management and planting protocols, yields were 58% and 70% of the 1,500 lb/ac target for the dryland and irrigated plots, respectively. Deep soil cores (up to 100 cm) were collected in 2019, at plot establishment and will be collected again in 2025, after two crop rotations. Objective 1.1 will continue under the new NP216 plan.
Under Objective 1.2, native wildflowers were planted on the borders of the irrigated and dryland plots starting in 2019. After the collaborating SY responsible for this Objective retired in 2020 and a replacement Entomologist was recruited in 2021, an optimal native wildflower habitat has been developed for provisioning of resources and refuge sites that increase pollinator abundance, diversity, and pollination of nearby crops. Pollinators are being sampled and metabarcoding is being used to identify the sources of the pollen collected from the bees. Objective 1.2 will not continue under the new NP216 plan. This work will continue under Objective 3A of the NP304 (6048-22000-046-000D).
Under Objective 2.1, ARS researchers in Tifton, Georgia, demonstrated that flue gas desulfurization gypsum (FGDG) and grass buffer strips (GBS) reduce edge-of-field nutrient losses from crop production under organic (broiler litter) fertilization. When fertilizing corn with broiler litter, the combined use of FGDG and GBS can reduce nitrogen (N) and phosphorous (P) loads by 35% to 60%. These results indicate the potential for FGDG and GBS to improve edge-of-field runoff water quality in cropping systems of the southeast, where broiler litter is commonly used as a fertilizer source.
Under Objective 2.2, scientists from Athens and Tifton, Georgia, demonstrated that the probability of detecting Salmonella in peanut hull litter is associated with the number of flocks raised on the litter and their grow-out period, while detection of Campylobacter is associated with the number of flocks and the litter pH. These results suggest that prevention of these pathogens’ persistence in broiler litter will require management interventions tailored to each pathogen.
The research plots used for Objective 2 have been dismantled and the equipment has been removed from the field.
Under Objective 3, ARS researchers in Tifton, Georgia continued to acquire daily weather data from the fully operational weather station installed at the Sumner Cooperator Farm (SCF). The cooperator can access the data and use it to monitor rainfall and soil temperature. The collaborating producer has used this data to make decisions regarding the need for irrigation and to determine appropriate crop planting dates. The completion of this Objective has been delayed due to critical vacancy of SY responsible for modeling. In addition, the collaborating producer did not make time to meet with the WholeFarm team and succumbed to COVID in 2022. The family has been restructuring the business and has not had time to meet with the WholeFarm team. The removal of this Milestone was requested in the 2023 Annual Report.
Accomplishments
1. The chemical composition of Miscanthus × giganteus stems is indicative of enhanced biofuel quality compared to the leaves. To reduce the carbon footprint of human activities, there is a growing need for alternative energy sources including the production of bioenergy feedstocks. Miscanthus × giganteus has high potential for feedstock use and studying the composition of its aboveground tissues is important for understanding feedstock quality for biofuel conversion and how crop residue quality may affect soil input management. ARS researchers at Tifton, Georgia determined that Miscanthus stems have a chemical composition indicative of enhanced biofuel quality compared to the leaves. Significant relationships were identified between tissue carbon and the mobile soil carbon pool suggesting a dynamic linkage between Miscanthus physiology and this active soil carbon pool. These results have implications for crop nutrient allocation and nutrient management practices. This information can facilitate a reduction in biomass conversion and fertilizer costs, and therefore maximize overall profitability.