Location: Soil Dynamics Research2020 Annual Report
1. Assess above- and belowground responses of pastures to elevated CO2 and their ability to help mitigate climate change via sequestration of CO2. 1a. Process and publish on biomass (above- and belowground) and soil physicochemical data, inclusive of soil C and N dynamics, from the 10-year CO2/N bahaigrass pasture study. 1b. Plant a Southeastern bermudagrass pasture to determine the effects of atmospheric CO2 level and N management on above- and belowground responses of the plant/soil system. 1c. Process and publish on soil flux of trace gases (CO2, N2O, CH4) from the 10-year CO2/N bahaigrass pasture study. 1d. Plant a Southeastern bermudagrass pasture to determine the effects of atmospheric CO2 level and N management on soil flux of trace gases (CO2, N2O, CH4). 1e. Determine the effects of elevated CO2 on efficacy of herbicidal control of weeds problematic in Southeastern agricultural systems. 1f. Work on effects of elevated CO2 on growth and efficacy of herbicidal control of herbicide resistant weed populations. 2. Manipulate fertilizers, soil amendments such as biochar, and irrigation in ornamental horticultural systems to reduce GHG emission and increase C sequestration. 2a. Identify best management practices (e.g., fertilizer placement, irrigation method) that reduce GHG emissions while optimizing growth for various horticulture crops. 2b. Determine the longevity of carbon in horticultural growth media (e.g., pine bark, clean chip residual, whole tree) following placement in the landscape. 2c. Investigate the effects of biochar in growth media (pine bark) on growth, nutrient retention, and GHG emissions in various ornamental horticultural crops. 3. Develop improved methods to utilize organic waste and soil amendments for soil and crop benefits while minimizing environmental degradation. 3a. Determine the rate of Flue Gas Desulfurization (FGD) gypsum needed to increase corn yield and reduce soluble P concentration in soil. 3b. Determine the rate of FGD gypsum needed to reduce P losses in runoff under no-till and conventional tillage. 3c. Determine the influence of poultry litter as a nutrient source for winter wheat and canola, and its residual effects on succeeding soybean and wheat crops. 3d. Evaluate the influence of poultry litter vs. inorganic fertilizer on crop production under different management practices. 3e. Develop a four-band implement for subsurface band application of pelletized poultry litter, poultry litter, and similar solid manures. The implement will use pneumatic conveying or a similar method to convey the product. 3f. Evaluate effectiveness of subsurface application of poultry litter for row crop production. 3g. Develop novel and economically viable uses for poultry litter, including innovative soil and manure analysis systems for precision manure management. 4. Develop management practices for economically and environmentally sustainable full life-cycle poultry production systems.
A long-term Southeastern bahaigrass pasture study will be terminated and a bermudagrass pasture study will be initiated. Both systems are exposed to current and projected levels of atmospheric CO2 and either managed (N added) or unmanaged (no N). Carbon flux to plants (biomass growth, allocation, and quality) and soil will be determined with supporting data on soil physicochemical properties. Emphasis will be given to measuring soil C and N dynamics and C storage, root growth, water quality, and GHG (CO2, N2O, and CH4) flux from soil. Using the same CO2 levels, container studies on weeds important to the southeastern U.S. (including those resistant to herbicides) will evaluate herbicide efficacy, regrowth, biomass, and tissue quality. In addition, research will evaluate production practices (in terms of such factors as fertilizer placement, growth media, and irrigation) to identify best management practices which ensure productivity, minimize GHG emissions, and maximize belowground C storage. Other work will examine how the application of organic waste to soil can improve soil conditions via C addition and provide nutrients needed for crop production. Poultry litter may be a viable fertilizer option for crop producers in the Southeastern U.S. given the large amounts of manure generated by the poultry industry. However, improper application of animal waste can contribute to environmental degradation such as increased hypoxia, eutrophication, human health problems, and greenhouse gas emissions. Due to these environmental and animal health concerns, studies will be established to develop improved methods to utilize waste products for animal and crop benefits. Research and development of technologies to recover phosphorous from manure, transform manure into secondary byproducts and find alternative, environmentally safe and economical usages of manure will be undertaken. Studies will be initiated to determine long term effects of poultry litter on plant yields, and soil physicochemical properties (including C storage) under various cropping systems. Further, different poultry litter application practices, such as subsurface banding, will be evaluated to determine their impact on nutrient loss and greenhouse gas emissions. Soil amendments (e.g., gypsum) will be evaluated both as a poultry house bedding material and as a soil amendment to determine the impact on animal production, plant responses, and the potential to reduce NH4 emissions and phosphorus (P) loss in runoff. Information acquired in the course of this project will be useful for developing improved poultry and crop production practices. Integrating data from these studies will be economically analyzed to aid understanding on how to adjust future poultry production and agronomic management practices to sustain productivity, while aiding mitigation of global change via increasing soil C sequestration and reducing greenhouse gas emissions.
World food stability depends on productive agricultural systems, but environmental concerns must be addressed for these systems to be sustainable. Research at the USDA-ARS National Soil Dynamics Laboratory, Auburn, Alabama, addresses potential impacts of management strategies on plant productivity, soil physicochemical properties [including soil carbon (C)], greenhouse gas (GHG) emissions, and nutrient losses. Global change research examined the impacts of elevated carbon dioxide (CO2) under differing pasture management practices (nitrogen) on C dynamics. Critical information on how pastures potentially mitigate or contribute to climate change through soil C storage and soil CO2 efflux is needed for efficient environmental management of these systems. During the 10-year bahaigrass pasture study, above- and belowground biomass data have been collected; soil cores for soil C as well as lysimeter solution samples have been collected and are being processed. Aboveground data from the bahaigrass pasture study has recently been published. A second long-term bermudagrass pasture study has been initiated. ARS research in Auburn, Alabama, is seeking to understand factors affecting trace gas (carbon dioxide (C), methane (CH4), and nitrous oxide (N2O)) efflux from agricultural and horticultural systems. Carbon dioxide efflux from the pasture study was continually monitored (24 hours per day) using Automated Carbon Efflux Systems (ACES) for the 10-year duration of the bahaigrass pasture study. Trace gas emissions (CO2, N2O, and CH4) were assessed weekly in this system. Gas samples were collected in situ using the static closed chamber method according to USDA’s Greenhouse Gas Reduction Through Agricultural Carbon Enhancement network (GRACEnet) protocols and analyzed using gas chromatography. In this study, soil C data have also been collected to determine soil C sequestration potential. These same data have begun to be collected in a new bermudagrass pasture study. In addition, a long-term evaluation of CO2 efflux (using ACES) from differing horticulture media has been initiated in plots established on an outdoor soil bin. Further, a sun vs. shade ornamental study evaluating trace gas efflux (using the static chamber method described above) as affected by fertilizer placement has been published. A study of alternative media mixtures using glasshouse-grown annuals to evaluate effects on growth and trace gas emissions has been completed. A study examining the effects of varying amounts of biochar in growth media on growth and trace gas efflux in day lilies is currently underway. Because of the growing environmental concern regarding organic waste disposal, field and laboratory studies were established to develop improved methods to utilize waste products for soil and crop benefits while minimizing environmental degradation. A series of field studies have been initiated in Alabama to evaluate management practices of fertilizer and poultry litter (PL) application methods as affected by tillage systems on crop production, greenhouse trace gas emissions, and nutrient losses to the environment. This includes studies on the integration of PL for canola production and refining the impact of poultry house management on nutrient content in PL. Research refined management practices for using gypsum as a poultry house bedding material to reduce Ammonia (NH3) emissions. New technology was developed for using neutron-gamma analysis in scanning mode for mapping of soil carbon across a field or landscape. Research also resulted in a new in situ, rapid, non- destructive technique of measuring C/N ration in compost using the inelastic neutron scattering method. Field study found that pulverized paper can be safely applied to degraded military training lands to improve establishment of desirable vegetation without any discernable negative consequences.
1. Management effects on greenhouse gas emissions in horticulture. Much of the work on reducing greenhouse gas (GHG) emissions and increasing carbon (C) sequestration has been conducted in row crop and forest systems; however, virtually no work has focused on contributions from sectors of the specialty crop industry such as ornamental horticulture. Ornamental horticulture impacts rural, suburban, and urban landscapes. Since little is known about the impact of the horticulture industry on these driving factors, the National Soil Dynamics Laboratory has an on-going joint effort with the Horticulture Department at Auburn University to determine baseline GHG emissions, develop strategies to reduce these emissions, and develop strategies to increase soil C storage. ARS researchers in Auburn, Alabama, conducted a study on fertilizer placement (dibble, incorporated, top-dressed) on growth and GHG emissions from a shade-grown species (hosta) and a sun-grown species (daylily). Dibbling fertilizer reduced both Carbon dioxide (CO2) and Nitrous oxide (N2O) emissions in both hosta and daylily. Methane release was low throughout the study and not impacted by fertilizer placement in both species. Findings indicate that dibble fertilizer placement could decrease both CO2 and N2O emissions. This work continues to identify best management practices that can reduce GHG emissions from container produced ornamental crops.
2. Response of a southeastern pasture system to elevated CO2. Both managed and unmanaged pasture systems in the Southeastern U.S. remain understudied agro-ecosystems in terms of the effects of elevated atmospheric CO2 concentration. ARS researchers in Auburn, Alabama, conducted a long-term bahiagrass pasture study managed with nitrogen (N) fertilization or no N fertilization for 10 years to assess biomass production under ambient or elevated (ambient plus 200 ppm) CO2. These two treatments represent managed and unmanaged pastures, both of which are common in the Southeast. Results show that N fertilization can significantly increase forage biomass production regardless of CO2 level. Elevated CO2 increased forage biomass only when fertilizer N was added. These findings highlight the importance of fertilizer N management to enhance pasture productivity under rising atmospheric CO2 levels.
3. Measurement of carbon: Nitrogen ratio in compost by neutron-gamma analysis. The carbon to nitrogen ratio of compost is traditionally determined by laboratory analysis which is time consuming and labor intensive since it needs many samples that require extensive preparation before analysis. Neutron-gamma analysis developed by ARS scientists in Auburn, Alabama, can be an alternative method for measuring compost C/N ratio. This is a non-destructive in situ method that requires no sample preparation or sampling since it measures very large volumes of material relative to traditional methods. Neutron-gamma analysis was found to be able to measure the C/N ratio in compost up to values of 25 and greater.
4. Integration of poultry litter and mineral nitrogen studied for growth and yield of winter canola. Winter canola (Brassica napins L.) has the potential to be used as a winter crop in the southeastern United States, but little is known about its nitrogen (N) management when grown in this region. Also, increasing fertilizer costs have increased interest in using poultry litter (PL) as an alternative nutrient source for crops in this region. However, evaluation of the use of PL on winter canola growth and yield is lacking. ARS researchers in Auburn, Alabama, conducted field studies to examine these issues in the southeastern US. Overall, combining poultry litter with commercial fertilizer resulted in an equivalent aboveground biomass, grain yield, and N uptake compared with the recommended commercial fertilizer treatment, while applying only PL was less effective. This study suggests that a combination of PL and commercial fertilizer N could provide sustainable canola yield production improvement in the southeastern United States.
5. Poultry production facilities production practices impacts poultry litter nutrient composition. It is believed that the poultry litter’s nutrient composition is influenced by poultry house management, however, limited information exists on how changes in poultry house litter management, which have greatly changed in recent times, potentially influence nutrients in the poultry litter. To fill this knowledge gap, ARS researchers in Auburn, Alabama, evaluated poultry production facilities to determine how their production practices impacted poultry litter and its nutrient composition. Specifically, this study assessed the frequency of cleanout, the depth of sampling, the size of birds reared and the number of flocks raised on the bedding to determine how it influenced macro and micro nutrient concentrations of the litter. The study indicated that management of the poultry houses greatly influenced the poultry litter nutrient concentrations, but averaged across all samples collected, the litter had a fertilizer grade close to that of 3-3-2 for N, phosphorous (P) and potassium (K), on an as-is basis.
6. Flue gas sulferization (FGD) gypsum can reduce ammonia (NH3) emissions from poultry houses without impacting climate change. Emission of NH3 from poultry hose bedding is an important concern for bird health and greenhouse gas (GHG) emissions are increasing at an unprecedented rate and are expected to double preindustrial revolution levels within this century. The effects of broiler house management on these emissions are unknown. ARS researchers in Auburn, Alabama, conducted a study to examine the effect of FGD gypsum bedding on efflux of NH3, CO2, CH4 and N2O. FGD gypsum bedding was compared with pine shavings and pine shaving+FGD gypsum (50:50 mix) and each litter type was either decaked or rotovated after each flock. This first examination of the effects of different litter materials on gas emissions from broiler house bedding showed that FGD gypsum can reduce NH3 concentrations, but has little impact on other greenhouse gas emissions.
7. New blower technology development for conveying broiler litter. Poultry production in the U.S. generates a large amount of poultry litter, which is a mixture of poultry manure and a bedding material, such as pine shavings. When the litter is removed from poultry houses, it is usually applied on pastures using a spreading machine to apply the litter on the field surface. A disadvantage of applying litter on the ground surface is that this allows nutrients, including phosphorus, to be carried away in runoff water, resulting in possible environmental degradation. ARS researchers in Auburn, Alabama, developed a prototype field implements for shallow subsurface band application of poultry litter which has been shown to be beneficial in reducing the amount of phosphorus and nitrogen nutrients in surface runoff water, compared to surface litter application. A blower for use on a subsurface banding implement was further developed and tested for conveying broiler litter as a component of this equipment. Poultry litter that was relatively dry was successfully conveyed by the blower, but the blower performance was not satisfactory when the litter was relatively moist.
8. Pulverized waste paper improves the rehabilitating of military training lands. ARS researchers in Auburn, Alabama, working with the US Army Corps of Engineers has developed technology to utilize pulverized waste paper for the rehabilitating military training lands. The United States Army produces a significant amount of classified paper waste that is pulverized to a fine consistency unsuitable for recycling. However, cheap, high quality organic materials such as classified paper waste are useful as soil amendments. Field studies found that pulverized paper can be safely applied to degraded training lands to improve establishment of desirable vegetation without any discernable negative consequences. When combining cost savings associated with landfill disposal of the paper with savings from greater land rehabilitation success, an estimated $300 per ton of diverted paper is realized. At the recommended application rate, this results in a cost savings of approximately $4,700 per acre. At the installation level, this equates to an estimated annual costs savings of $20,000 with 70 tons of paper diverted. Application of paper waste to soils had no adverse environmental effects, improved soil physiochemical properties, and facilitated establishment of desirable native vegetation.
9. U.S. patent method developed for creating soil carbon content maps. Soil carbon mapping is extremely useful in assessing the effect of land management practices on soil carbon storage. ARS researchers in Auburn, Alabama, developed a method of using neutron-gamma analysis in scanning mode for mapping of soil carbon (patent pending). A Global Positioning System (GPS) device and software required to simultaneously acquire gamma signals and geographical positions during scanning operations were added to an existing measurement system. The reliability of soil carbon measurements in scanning mode was demonstrated to be in agreement with results acquired from traditional soil sampling. Neutron-gamma analysis technology can greatly facilitate timely construction of soil carbon maps. This methodology has currently been licensed for commercialization.
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Murphy, A., Runion, G.B., Prior, S.A., Torbert III, H.A., Sibley, J.L., Fain, G.B., Pickens, J. 2019. Effects of fertilizer placement on greenhouse gas emissions from a sun and shade grown ornamental crop. Journal of Environmental Horticulture. 37(3):74-80.
Ferreira, C., Bassaco, M., Pereira, M., Pauletti, V., Prior, S.A., Motta, A. 2020. Dendrometric analysis of early development of Eucalyptus urophylla x Eucalyptus grandis with gypsum use under subtropical conditions. Floresta e Ambiente (Forest and Environment). 27(1):e20190095. https://doi.org/10.1590/2179-8087.009519.
Barbosa, J.Z., Poggere, G.C., Teixeira, W.W., Motta, A.C., Curi, N., Prior, S.A. 2019. Assessing soil contamination in automobile scrap yards by portable X-ray fluorescence spectrometry and magnetic susceptibility. Environment Monitoring and Assessment. 192:46. https://doi.org/10.1007/s10661-019-8025-8.
Lin, Y., Watts, D.B., Kloepper, J.W., Feng, Y., Torbert III, H.A. 2019. Influence of plant growth-promoting rhizobacteria on corn growth under drought stress. Communications in Soil Science and Plant Analysis. 51(2):250-264. https://doi.org/10.1080/00103624.2019.1705329.
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Tekeste, M., Way, T.R., Syed, Z., Schafer, R. 2020. Modeling soil-to-bulldozer blade interaction using the discrete element method (DEM). Terramechanics Journal. 88:41-52. https://doi.org/10.1016/j.jterra.2019.12.003.
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Motta, A., Barbosa, J., Magri, E., Pedreira, G., Santin, D., Prior, S.A., Consalter, R., Young, S.D., Broadley, M.R., Benedetti, E. 2020. Elemental composition of yerba mate (Ilex paraguariensis A.St.-Hil.) under low input systems of southern Brazil. Science of the Total Environment. 736:139637. https://doi.org/10.1016/j.scitotenv.2020.139637.
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Barbosa, J.Z., Motta, A.C., Dos Reis, A.R., Correa, R.S., Prior, S.A. 2019. Spatial distribution of structural elements in leaves of Ilex paraguariensis: Physiological and ecological implications. Trees. 34:101-110. https://doi.org/10.1007/s00468-019-01900-y.
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Yakubova, G.N., Kavetskiy, A., Prior, S.A., Torbert III, H.A. 2019. Application of neutron-gamma analysis for determining compost C/N ratio. Compost Science and Utilization. 27(3):146-160. https://doi.org/10.1080/1065657X.2019.1630339.
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