Project : USDA ARS

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Research Project: Innovative Manure Treatment Technologies and Enhanced Soil Health for Agricultural Systems of the Southeastern Coastal Plain

Location: Coastal Plain Soil, Water and Plant Conservation Research

2024 Annual Report

Objectives
1. Develop and test improved tillage, cover crops, and biomass management to enhance soil health and resiliency and improve long-term agricultural sustainability and productivity in the Southeastern Coastal Plain. 2. Develop manure treatment and handling systems that minimize the emissions of greenhouse gases, antimicrobial resistance genes, odors, nutrients, and pathogens to improve soil health and water quality outcomes. 2.A. Develop new, affordable treatment technologies for removal/recovery of manure nutrients from swine, poultry, and dairy operations and industrial/municipal wastes. 2.B. Conduct multiscale assessment of the impact of manure treatment and nutrient management systems on agricultural ecosystem services for soil conservation and water quality protection. 2.C. Increase the value of agricultural residuals using hydro- and thermal technologies. 2.D. Develop improved techniques for quantifying ammonia deposition near livestock production sites. 3. Develop biostimulants and other soil amendments and assess their ability to improve soil health, nutrient cycling, and soil fertility and resiliency. 3.A. Develop and assess microbial inoculants and other soil amendments for their ability to enhance revegetation and improve drought resistance in remediated and degraded soils. 3.B. Develop biochar and hydrochar applications to improve their use in agricultural and non-agricultural settings.

Approach
New management practices and treatment technologies are required to help crop and animal producers increase soil productivity and health; reduce unwanted atmospheric emissions, excessive nutrients, and pathogens; and improve affordability of animal waste treatment. To meet these needs, we aim to develop in this project: i) knowledge of the impact of crop systems and novel soil amendments on the soil ecosystem and nutrient and carbon cycling; ii) new manure treatment technologies; iii) model-based approaches to evaluate nutrient and gas emission reduction strategies; iv) management strategies to reclaim degraded soils; v) management practices to reduce pathogens and antimicrobial resistance genes in agricultural wastes; and vi) knowledge of and metrics for properties that make a soil more productive. The project has three objectives. Improved tillage, cover crops, and biomass management will be developed to enhance soil health and resiliency and improve long-term agricultural sustainability and productivity in the Southeastern Coastal Plain. Innovative manure treatment systems will be developed to minimize greenhouse gas emissions, and reduce antimicrobial resistance genes and pathogens, odors, and excess nutrients, to improve soil health and water quality outcomes. The manure treatment technologies include recovery of ammonia using gas-permeable membranes, enhanced deammonification treatment, and engineered biochar and hydrochar systems to valorize agricultural residuals. Manure management's beneficial impact will be assessed using multiscale models, and improved techniques will be used to assess ammonia emissions from manure, including deposition near livestock operations. Biostimulants and other soil amendments will be investigated for their ability to improve soil health, nutrient cycling, soil fertility, and resiliency. Research methods include laboratory, pilot-scale, and field-scale experiments using modern analytical equipment. Research products will advance the state-of-the-science for more effective conservation and management of soil resources, innovative animal waste treatment technologies as environmentally safe alternatives to traditional land application, and guidelines for beneficial byproduct utilization.

Progress Report
Soybean and cotton biomass samples were collected at the end of the 2023 growing season, processed, and analyzed for total carbon and nitrogen. Cotton lint and soybean grain yields were also determined and compiled for the 2023 season. Following the cash crops harvest, a four-species cover mixture was planted in December 2023. Cover crop biomass yield data were collected before their termination in spring of 2024 and currently been processed to be analyzed for nutrient content. A LiCOR LI-8100A Automated Soil CO2 Flux System is installed, and hourly CO2 measurements are being recorded. A summary of the soil CO2 flux data from years 1 and 2 showed no difference in soil CO2 flux among the different tillage systems. This was not expected, and a modification has been made to the way in which the system was deployed. It is expected that any difference in soil CO2 flux among the tillage management will be captured by the current system deployment modification. Soil samples were collected immediately following cotton and soybean harvest in Fall of 2023, and after cover crops termination in spring of 2024. The soil samples are currently being processed to be analyzed for all soil chemical properties including pH and electrical conductivity, soil carbon and nitrogen pools, as well as other essential nutrients including soil P. Soil samples were collected after cotton and soybean harvest in fall 2023, and after the cover crop termination in spring 2024 have been processed and analyzed for different soil carbon and nitrogen pools. The samples are currently awaiting soil enzyme analysis for beta-glucosidase and acid phosphatase. Cooperated in a Cooperative Research and Development Agreement (CRADA) with commercial partner to pilot test nitrification of anaerobically digested swine wastewater and water recycling into the barns in a closed loop to improve the health of the animals and biogas production in a Department of Energy project. Cooperated in a CRADA with commercial partner Pancopia to test water reuse using anammox two-stage filters in a NASA project. Development of improved treatment methods for recovery of N and P from manure using gas-permeable membranes. Conducted batch treatment experiments using electrochemical methods and gas-permeable membranes to recover ammonia and phosphorus from liquid swine manure simultaneously. The research led to a new invention disclosure. Testing of phosphorus and protein extraction from manure using acid precursors. Testing was completed to evaluate the use of lactose waste as an acid precursor to extract phosphorus from dairy manure. Optimized acid rate for P extraction using selected anaerobic lagoon sludge. Further treatment to reduce S impurities, and solid/liquid separation conducted prior to calcium diphosphate purification. State-level geolocations of swine CAFO farms were used to map the spatial distribution of swine operations for watersheds hydrologic unit codes HUC4, HUC6, HUC8, HUC10 and HUC12 in North Carolina. Updated IPCC Tier 1 and Tier 2 methodologies were separately used to quantify methane emissions from feeder-to-finish swine waste treatment lagoons in North Carolina. A machine learning filtering algorithm was developed and refined for retrieving swine CAFO lagoon’s properties from aerial RGB and NIR images. Produced 3 kg of plastichar samples made from cotton gin trash and plastic film waste and shipped to LSU for evaluating the potential of using the plastichar as a soil amendment to improve tomato yields and reduce greenhouse gas emissions. Determination of pathogen kill rates, and degree of deoxyribonucleic acid (DNA) degradation using Escherichia coli and Enterococcus sp. as proxy organisms in swine manure studies, under different hydrothermal carbonization treatment (HTC) regimens is undergoing. Analyzed the field NH3 deposition data from a commercial dairy farm in Idaho and ran STAGE computer program to estimate NH3 deposition rates and compared with the difference in emission rates estimated by the backward Lagrangian stochastic inverse dispersion model. Samples were collected and processed in November 2024, with DNA and soil enzyme analyses conducted to look at influence of inoculation with locally effective microbial communities on remediation. Soil health analyses were also conducted to look at impact of compost application rates on revegetation outcomes. Plans between ARS, the US Environmental Protection Agency, collaborators at The Ohio State University, and the City of Webb City were made to continue site maintenance and plan for Fall 2024 sample collection. Plots were established for a third year, with microbial inoculant (combination of 4 microbial species and several arbuscular mycorrhizal fungi) applied. Humic acids were applied to additional plots to act as a control (humic acid is often used as a carrier for microbial inoculants, but serves as a biostimulant of its own accord), along with no treatment plots. Early season samples were collected, and soil enzyme analyses conducted. Late season samples are pending. Performed batch sorption experiments to evaluate the binding of phosphate by inactivated, magnesium-activated, and iron-activated biochars produced from poultry litter. Langmuir isotherm models were fit to the measured data to determine the biochar’s phosphate sorption maximum. Correlated sorption maximum values to chemical activation levels and pyrolysis temperatures to optimize biochar production conditions. Conducted batch sorption experiments to evaluate cadmium and copper binding by poultry litter- and swine manure-derived biochar, hydrochar, and plastichar as a function of solution pH, initial metal concentration, biochar dosage, and time . Fit a pH- and time-dependent sorption model to the measured data to determine the optimal reaction conditions to maximize metal binding by biochar from solution.

Accomplishments
1. Method for converting poultry litter into an environmentally-friendly phosphorus adsorbent. The commercial poultry industry in the United States produces between 6-18 million tons of poultry litter per year as a waste product. Poultry litter is a nutrient-rich mix of chicken feathers, excreta, and bedding material that is commonly applied to agricultural soils as a low-cost fertilizer. However, the over-application of poultry litter can cause serious water quality problems due to high concentrations of phosphorus in agricultural runoff. ARS researchers at Florence, South Carolina, developed an alternative use of poultry litter to address water quality problems caused by its overapplication. Specifically, they converted poultry litter into a soil amendment using a two-step process. First, poultry litter was treated with a concentrated magnesium solution. Second, the magnesium-treated poultry litter was exposed to high temperatures in the absence of oxygen to produce biochar, a charcoal-like substance with a highly reactive surface. The biochar was able to bind phosphorus, suggesting the material can be used in soils to prevent the movement of phosphorus from agricultural areas to the surrounding environment. This work demonstrates the beneficial use of an abundant agricultural waste product and has the potential to be a win-win for both the poultry industry and environment.

U.S. DEPARTMENT OF AGRICULTURE

Coastal Plain Soil, Water and Plant Conservation Research: Florence, SC