Obj 1. Develop ecological and sustainable site-specific agriculture systems, for cotton, corn, wheat, and soybean rotations. 1: Geographical coordinates constitutes necessary and sufficient cornerstone required to define, develop and implement ecological/sustainable agricultural systems. 2: Develop methods of variable-rate manure application based on soil organic matter (SOM), apparent electrical conductivity, elevation, or crop yield maps. 3: Relate SOM, electrical conductivity, and elevation. Obj 2. Develop sustainable and scalable practices for site-specific integration of animal agriculture byproducts to improve food, feed, fiber, and feedstock production systems. 1: Quantify effects of management on sustainability for sweet potato. 2: Balance soil phosphorus (P)/micro–nutrients using broiler litter/flue gas desulfurization (FGD) gypsum. 3: Effects of site-specific broiler litter applications. 4: Manure application/crop management practices in southern U.S. 5: Compare banded/broadcast litter applications in corn. 6: Develop reflectance algorithms for potassium in wheat. 7: Determine swine mortality compost value in small farm vegetable production. Obj 3. Analyze the economics of production practices for site-specific integration of animal agriculture byproducts to identify practices that are economically sustainable, scalable, and that increase competitiveness and profitability of production systems. 1: Evaluate economics of on-farm resource utilization in the south. Obj 4. Determine the environmental effects in soil, water, and air from site-specific integration of animal agricultural and industrial byproducts into production practices to estimate risks and benefits from byproduct nutrients, microbes, and management practices. 1: Quantitatively determine bioaerosol transport. 2: Role of P and nitrogen (N) immobilizing agents in corn production. 3: Assess impact of management on water sources. 4: Impact of FGD gypsum/rainfall on mobilization of organic carbon/veterinary pharmaceutical compounds in runoff/leached water. 5: Assess soil microbial ecology, antibiotic resistance, and pathogen changes using manure and industrial byproducts in crop production systems. 6: Develop nutrient management practices for sustainable crop production. 7: Develop nutrient management practices for reclaimed coal mine soils. 8: Determine effects of poultry litter/swine lagoon effluent in swine mortality composts. 9: Determine survival of fecal bacterial pathogens on contaminated plant tissue. 10: Identify agricultural/industrial byproducts that modify the breakdown of organic matter. Obj 5. Integrate research data into regional and national databases and statistical models to improve competitiveness and sustainability of farming practices. 1: Develop broiler house emission models. 2: Apply quantitative microbial risk assessment models to animal agriculture/anthropogenic activities. Obj 6. Develop statistical approaches to integrate and analyze large and diverse spatial and temporal geo-referenced data sets derived from crop production systems that include ecological and natural resource based inputs. 1: Develop novel methods of imaging processing.
Multidisciplinary approaches will be utilized in developing sustainable and competitive agricultural practices for crop management systems. Some approaches will use animal, municipal, and industrial waste as fertilizers and organic soil amendments in crop management systems in precision agriculture ways. Presence, prevalence, and fate of nutrients, gaseous emissions, bacterial approaches, and antibiotic resistance associated with these wastes when applied to soils in cropping systems will be addressed. Work will be done in cooperator animal feeding operations (AFO), farms, and experiment station plots. Off-site transport of nutrients, pathogens, and antibiotic resistant bacteria will be determined. Statistical models will be developed for geo-referenced measurements of farming practices and improvements to mixed model analysis methodology will be developed. Remotely sensed data will be combined with on-site field measurements to develop site-specific prescriptions for application of crop management inputs. Information will be developed into best management practices to protect the environment and human and animal health by maximizing crop nutrient utilization, minimizing bacterial contamination and antibiotic resistance, and reducing ammonia and greenhouse gas emissions. Agricultural models will be used to predict sustainability and competitiveness of management practices developed and implemented into best management practice recommendations.
Objective 1: Prescription-based variable rate manure application. A 9-acre cotton field on a commercial farm was divided into 0.5 to 1.0 acre plots and poultry litter applied to each plot using a prescription written according to inherent soil variation in each plot. The variation in each plot in terms of soil organic matter and elevation (topography) was mapped and the prescription was prepared based on these maps. The prescription was written and the application of litter made so that parts of the plots with low soil organic matter or high elevation receive the higher rates. At the end of the season, high-resolution geo-referenced yield data were collected using a two-row cotton picker equipped with yield-monitor sensors. Geo-referenced soil samples were also taken using hand probes from pre-determined sampling points. Preliminary conclusions are that cotton produced more lint if fertilized with litter regardless of the prescription method. Applying the litter using either prescription methods was superior to blanket application which suggests the variable rate application based on organic matter or elevation map may be a promising method for manure management in cotton. Different categories of soil electrical conductivity (ECa) were derived in a 160 acre field on a private farm using Veris 3100 data collected in 2005 and 2006. The research will combine the Geographic Information System (GIS)-derived ECa categories with two additional data sets, Normalized Difference Vegetation Index (NDVI) and Light Detecting and Ranging (LiDAR) elevation, to determine how topography co-variates affect the different ECa categories. New experiments began in the summer of 2016 with West Texas cooperators. Objective 2: Measuring the value of poultry litter empirically. Applying poultry litter by broadcasting on the soil surface is inefficient because nutrients, nitrogen in particular, are lost to volatilization and runoff. Applying litter in subsurface bands, on the other hand, is efficient because nutrient losses are minimal. The value of 1 ton per acre of litter applied by subsurface banding is expected to be substantially greater than the same amount applied by surface broadcast. Preliminary results show that corn grain yield is greater if the same amount of litter is applied by subsurface banding versus surface broadcasting. The yield differences are greater at low rates of litter and the differences diminish as the rate increases. In a greenhouse study, wheat (cultivar Magnolia) was grown in large pots filled with fine sand. Plants were fertilized with three nutrient solutions of complete ½ strength Hoagland, ½ Hoagland minus potassium (K) and ½ Hoagland minus nitrogen (N). Measurements of leaf reflectance and transmission in narrow wavebands 450-1095 nanometer (nm) range, leaf chlorophyll, and K and N concentrations in biomass were made. Plant biophysical data have been analyzed statistically and spectral data have been organized in an electronic database. A similar study was conducted with soybean in winter 2015. The third annual fall treatments were completed in a 4 acre field testing effects of swine mortality compost with and without flue gas desulferized (FGD) gypsum on soil organic matter (SOM). Soil samples collected in spring 2016 were tested for carbon (C), nitrogen (N), and organic matter and levels were compared with pretreatment levels. Analysis showed trending increases in C, N and SOM in compost-treated soil, with or without FGD-gypsum, but treatment differences were not statistically significant. Long-term increases in SOM in this sandy soil will require continued applications. A system using poultry litter and cover crops with reduced tillage and supplemental phosphorus and potassium fertilization produced yields equal to conventionally managed systems of sweet potato production and soil quality indicators were higher than the conventional inorganic fertilizer managed system. A combination of poultry litter, FGD gypsum and cover crops in a no-till system of corn-soybean rotation produced plants with greater height, leaf area index and chlorophyll content than inorganic fertilizer. Objective 3: A manuscript was published describing energy independence of a broiler farm through use of local resources and bioenergy which included biogas from anaerobic digestion, biomass of poultry litter and community organic wastes, and solar arrays. This farm produces meat chickens, liquid fertilizer and compost as marketable products. Model development for solar-electric stand alone installations is underway. Objective 4: Cooperator farms were intensively sampled for the presence of bioaerosols during land application of swine effluent and poultry litter. Three six-hour replicate impingement samples, as well as 100 liter (L) impaction samples were collected approximately 100 meters (m) downwind of litter application and 1000 m downwind of the complete swine farm operation. Aerosol samples were collected from April through September and processed for cultivated antibiotic resistant bacteria and pathogens, as well as indicators, pathogens, and antibiotic resistance genes. The role of phosphorus (P) and nitrogen (N) immobilizing agents on litter P and N dynamics, greenhouse gases (GHG) emissions and sustainable corn production under reduced tillage system was continued. Complete 3 years research to select best management practices for using animal and industrial by-products for corn production with reduced GHG emissions. Water samples were collected from a cooperator farm from locations directly impacted by land-applied fertilizer and runoff. Samples were collected from a known flood zone on the farm during the winter throughout early spring. Escherichia coli, Clostridium, enterococci, and staphylococci isolates were collected from each site. Samples were also collected from 6 small creek sample sites traversing a small community to determine impact from a wastewater treatment plant. Samples were collected to determine the presence of E. coli and antibiotic resistant bacteria. A new sample site location was identified and intensively sampled prior to implementation of confined feral hogs to determine impact of feral hogs on water quality. The sample site is located on the Mississippi State University South farm research plots. Quantitative microbial risk analyses were performed on laboratory-based macrocosms simulating the effect of organic matter on fecal-borne bacterial pathogens. Inactivation rates were calculated for each simulated scenario and implemented into appropriate risk models. Lab microcosms were also established to determine the effect of land-applied oxytetracycline to ryegrass microcosms. Applied E. coli was sampled to determine pre-exposure resistance to post-exposure resistance. Lab enrichment microcosms were also simulated using similar scenarios without the effect of soil and ryegrass. Next generation sequence analysis was conducted on samples collected from banded manure treatments. Additionally, the effect of high inputs of organic matter on soil microbial communities was investigated on experimental research farm plots and commercial farms. Pelletized biosolids, at the equivalent of a total 5 year rate, was applied to research plots to determine if positive residual effect on soil-health and -microbial levels can persist over time. A laboratory microcosm system, for testing effects of adding FGD-gypsum on the swine mortality composting process and product, was modified to improve control of composing temperatures. Addition of supplemental cooling air inputs allowed composts to maintain 55-60C for longer periods and prevented excessively high temperatures (greater than 65C) that kill desirable composting microbes and drive off more N. Research to evaluate systems of post-reclamation of land after surface mining of coal is under way. Soil samples are being taken from different reclamation ages and will be analyzed for soil bulk density, porosity, microbial activities, organic carbon, soil aggregate stability, infiltration rate, soil compaction, and soil moisture retention under pasture and forest ecosystems. Addition of organic amendment with FGD gypsum improved soil structure as evidenced by greater soil carbon, aggregate stability, and smaller bulk density compared to inorganic fertilizer. Laboratory studies indicate that lignite coal applied with broiler litter substantially reduced nitrogen losses from litter. Field results show that plant height, leaf area index, chlorophyll content, and in-season available soil nitrogen are greater in broiler litter plus lignite than in broiler litter alone plots. In a forage system broiler litter was compared to broiler litter plus FGD gypsum and lignite. Leaching loses of N, P, copper, zinc, and dissolved organic carbon was less in plots receiving litter plus FDG gypsum and lignite than in litter alone. Objective 5: A manuscript on implications of intensive spatial sampling of broiler house litter and gaseous flux is currently being written. It is the culmination of a decade of litter/gas studies and the basis of the next generation ammonia emission model and broiler litter characterization data base. Ongoing research has developed best management practices to minimize greenhouse gas (GHG) emissions from soil in corn farming with two years of data entered into template and submitted to the GRACEnet database. Inactivation coefficients were modeled for a number of microcosm scenarios using varying levels of climate/organic matter/pathogen scenarios. Coefficients were validated using previous models and published research. Pathogens included: Escherichia coli O157:H7; Salmonella enterica; Listeria monocytogenes; and other bacteria and indicator viruses. Additionally, an antibiotic resistant pathogen risk model was developed using antibiotic resistance epidemiological data and published risk models.
1. Antibiotic resistance may not be selected for under typical environmental soil conditions. The prevailing hypothesis is the presence of antibiotics applied to land via manure application will select for antibiotic resistance. However, ideal growth conditions, which are not typically found in the environment, are necessary to promote selection for resistance. ARS researchers at Mississippi State applied oxytetracycline to soil at sub-clinical levels to simulate typical exposure levels. Oxytetracycline susceptible/resistant Escherichia coli and heterotrophs were measured in soil and enrichment broth microcosms. Overall, E. coli remained susceptible following 60 d, while antibiotic-resistant soil bacteria remained at baseline levels. Additionally, non-treated enrichment broth microcosms selected for resistant E. coli at the same rate as treated enrichments. This study suggests the land application of manure-borne tetracycline may not select for antibiotic resistant bacteria under typical agricultural environmental conditions and suggests antibiotic resistant bacteria and genes are selected for upstream of land application.
2. Effectiveness of applying 50% of nitrogen (N) as poultry litter to a mixed pasture of bermudagrass and tall fescue is affected by time of nitrogen applications. ARS researchers at Mississippi State, Mississippi and Lexington, Kentucky found that timing of N limited the growth competition of bermudagrass and tall fescue. Timing N and poultry litter applications to favor tall fescue increased nutritive value of mixed herbage during the warm-season. When the goal of management is to favor cool-season tall fescue, poultry litter should be applied in October and January. When the goal is to optimize the bermudagrass, poultry litter should be applied in January and March. These research results addresses concerns of farmers about the price of inorganic N fertilizer and best use of litter, and the new USDA-NRCS standards that set allowable fertilizer rates on the basis of agronomic soil test phosphorus thresholds.
3. Winter cover crop is beneficial for no-till cotton in upland soils. Upland soils are generally low in nutrient content, marginal in organic matter, and vulnerable to erosion and nutrient losses, which negatively affects crop production and contributes to nonpoint-source pollution of water bodies. The potential of losing nutrients from no-till cotton when fertilized with broiler litter in areas in the southeast with high rain is challenging. ARS scientists at Mississippi State, Mississippi, found that cotton responds better to broiler litter in the presence of cover crop residue rather than just applying broiler litter alone. A cover crop significantly increased cotton lint yield, particularly in a dry year, confirming the benefits of cover crop as an important conservation practice for no-till cotton. Results obtained from this study provide useful information and scientific knowledge for the cotton producers who are showing interest in integrating cover crops into their common crop rotations and establishes grower’s confidence in adopting sustainable management practices.
4. Residual effect of banding placement of pelletized broiler litter maintains cotton yield and economically benefits cotton growers. Many row crop farmers in the southeastern U.S. who use broiler litter to fertilize cotton, disregard the residual nitrogen (N) supplied by the broiler litter application in the preceding year, and apply the full N needs of cotton from inorganic N sources the first year after broiler litter use ceases. This practice often leads to over-application of N and associated economic loss and potential environmental harm. ARS scientists at Mississippi State, Mississippi, evaluated the residual effects of precision band placement of pelletized broiler as compared to recommended commercial N fertilizer and found that similar yield was sustained when the prior litter plots were fertilized with a reduced rate of inorganic fertilizer N, thus taking advantage of the litter residual N. This strategy reduces the use of inorganic N fertilizers and enables growers to maximize the return on their nutrient management practices.
5. Bioenergy options for meat chicken growers. In the United States, broiler chicken production is essential to provide our most consumed meat. Escalating energy costs, often comprise more than 25% of gross receipts; thus, growers need options to reduce energy costs and to remain profitable. ARS researchers at Mississippi State, Mississippi, identified novel farm networks utilizing solar-thermal, biomass boilers and anaerobic digester technologies. This resulted in broiler growers and researchers, globally, being introduced to a system that works towards a more profitable and sustainable business model that minimizes the environmental footprint of the operation. The result is that growers may choose to adopt comprehensive systems to attain energy independence or can affordably put in place individual technologies scalable to farm needs. The potential impact of adopting these sustainable farm strategies would reduce farm dependence on outside energy sources by 80%, reduce ammonia generation in broiler houses, increasing profits, and reduce landfill inputs for the surrounding community.
ARS scientists at Mississippi State, Mississippi, established soil amendments experiments on a cooperator’s small vegetable farm to evaluate the long term effects on soil organic matter of adding swine mortality compost and municipal ‘class A’ biosolids. The amendments are underutilized byproducts that may provide lower cost alternatives to commercial amendments and fertilizers for small farm fruit and vegetable production. ARS scientists at Mississippi State, Mississippi participate in activities targeting minority, historically under-served operators/stakeholders through a standard cooperative agreement with a woman-owned farm (small broiler operation) to determine litter gases and nutrients within modern commercial broiler houses, to develop southern U. S. confined animal feeding operation emission factors, and to utilize litter in sustainable agriculture fertilization studies to protect water quality and prevent pathogen transfer. Grower transfers data informally as collected through participation in state associated grower advisory council and young farmer/rancher committee.
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