Location: Southeast Watershed Research
2019 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
Research area was cleared of pigeon pea and rye crops planted in the previous year on trial basis. Layout of plots including replication and randomization was completed. The Veris MSP3 soil EC-OM-pH mapping system was run on research area and data were acquired. Soil samples were taken and analyzed to determine fertility status and for fertilizer recommendations. Planted 1st year crops of a 3-year rotation on 48 irrigated and 48 dryland plots each 12 ft by 45 ft (Corn, cotton, peanut, Tifleaf 3 as forage, and pigeon). Performed routine farming practices. Made first cut of the Tifleaf 3 forage. Installed soil water content and soil water potential sensors at all plots, logging equipment with solar charged batteries (one for paired plots), and modems to transmit data to base station. Modified irrigation gun for flow monitoring and applied 4 irrigation runs.
Modified set up for field edge native wildflower habitat to enhance pollination and populations of pest arthropod natural enemies. Reduced area of Indian blanket (IB) flowers planted previous year on trial basis. Added two species of flowers (Lemon mint and Black-eyed Susan). Started weekly insect sampling during reproductive stage of crops. This year, we determined that the plan to sow additional IB flowers at mid-season was not a good strategy. A better strategy is to sow an additional later season plant (i.e. perennial lupine) that is more conducive to especially larger bees and their preferences. Promoting higher bee diversity is the main goal determined by recent and expanding studies to increase pollination services.
Continued research activities on 60 small plots at Gibbs Farm under Phase II (2017, 2018, and 2019) to assess the impacts of application of flue gas desulfurization gypsum and poultry litter on corn production, soil properties, and nutrients in runoff. In Phase II, poultry litter and gypsum rates are set at 2 tons per acre per year down from the 6 tons per acre per year during Phase I (2014, 2015, and 2016). Successfully grew a winter rye cover and determined biomass. Soil samples were taken and analyzed for determining fertility status. The rye was rolled and chemically killed before incorporating into the soil by disking and planting of the 2019 summer corn crop which is expected to be harvested in September 2019. Surface runoff samples were obtained from two storm events which, however, did not prove strong enough to yield runoff from all plots. The government shutdown of 12/22/2018-01/25/2019 had negative impact because we were not able to collect runoff samples during the period. Following opening of the government, we noticed there were samples but could not identify the particular storm they were from and therefore had to discard them. This is unfortunate because we have not had storms since that produced same caliber of samples – a loss to our overall assessment of management and environmental effects on water quality.
Soil samples were collected and sent to the Bacterial Epidemiology and Antimicrobial Resistance Research Unit U.S. National Poultry Research Center Athens, Georgia, for related research. The unit has developed and validated a targeted gene sequencing approach that will enable the detection of antibiotic resistance genes present in these samples at a higher depth of coverage. It is also in the process of validating a digital qPCR assay that will allow the quantification of 48 genes in 48 samples at once. This PCR targets pathogens and antibiotic/metal resistance genes associated with “poultry production”. Both methods would be used to determine the microbiota and resistome (metal and antibiotic resistant genes) present in the soil. So far, environmental DNA extracted from flue gas desulfurized gypsum (FGDG) was too low for molecular work. Consequently, FGDG sampling and analysis has been dropped. The unit will continue to extract environmental DNA from amended soils and other amendments used. Runoff samples will be sent if/when runoff occurs from all plots – expected in the July-September time period.
The research is partially funded through a Trust Fund Cooperative Agreement with Southern Company Inc. and Duke Energy.
Continued to acquire from one minute up to daily weather data from the fully operational weather station installed at Wilson Farm (Cooperator). This station has proven popular with the Cooperator as he uses it to monitor rainfall and soil temperature to adjust his farming practices. He was able to plant cotton ahead of other farmers in the area because he determined from the data that soil temperature was high enough to do so. Locations for upstream and downstream creek flow measurement were assessed and types of suitable structures discussed. Dry weather has delayed anticipated start of bi-weekly (every two weeks) creek water sample collection in June 2019 (creek dry). The situation might last until December 2019. Processing and analysis of soil core samples collected previously continued as technical help became available. Other activities are on hold due to scientist and technician position vacancies.
Accomplishments
