Location: Soil Dynamics Research2012 Annual Report
1a. Objectives (from AD-416):
There is an urgent need to develop organic waste management systems in the southeastern United States that preserve and improve the soil resources and provide for environmental quality. The objectives of this project are to: 1) develop improved management practices and/or technologies for using manures and other byproducts (e.g., FGD gypsum) to reduce nutrient loss to the environment; 2) determine and compare the impacts of poultry litter and fertilizer application practices on atmospheric emissions of greenhouse gases; and 3) in cooperation with other ARS locations, develop and evaluate new technologies (e.g., subsurface banding) for the application of poultry litter in agricultural systems.
1b. Approach (from AD-416):
Application of organic waste to soil can improve soil conditions and provide nutrients needed for plant production. Poultry litter use seems to be a viable option for producers in the Southeastern Region, especially since the bourgeoning poultry industry generates large amounts of manure, and interest in utilizing animal manure as a fertilizer source has increased due to rising costs of inorganic fertilizers. However, improper application of animal manures in agriculture can contribute to environmental degradation such as increased hypoxia, eutrophication of surface waters, human health problems, and greenhouse gas emissions. Because of this growing environmental concern, field and laboratory studies will be established to develop improved methods to utilize waste products for soil and crop benefits while minimizing environmental degradation. In addition, manure’s interaction with tillage and cropping systems is not well understood. Thus, the environmental impact of poultry litter addition to soil must be quantified, and improved management techniques for application need to be developed for sustainable use in agriculture. Studies will be initiated to determine long term effects of poultry litter on plant yields and soil physical properties under various tillage and cropping systems. 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 to determine the impact on plant responses and the potential to reduce phosphorus (P) loss in runoff. Information acquired in the course of this project will be useful for developing agricultural practices using poultry litter as a nutrient source for environmentally sustainable plant production.
3. Progress Report:
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. ARS researchers at the NSDL, Auburn, AL have initiated a series of field studies in Alabama to evaluate the impact of fertilizer and poultry litter application methods as affected by tillage systems on crop production and greenhouse trace gas losses to the atmosphere. A four-trench litter applicator implement was designed, constructed, and used for applying poultry litter in field experiments. This unique equipment was patented in 2010. Studies utilizing the litter applicator have demonstrated a substantial reduction in phosphorus in runoff compared to surface application of poultry litter. Studies of soil Nitrogen (N) mineralization as affected by microorganism populations and manure handling methods were conducted. New municipal solid waste processing technology was studied which reduces volume and provides beneficial reuse applications for soil improvement. Experimental evaluations of alternative tree species (sweetgum, hickory and eastern red cedar vs. pine bark) as an alternative substrate for use in horticulture container production were studied. Research was also conducted on the utilization of gypsum as a soil amendment to reduce Phosphorus (P) losses to the environment from poultry litter applications.
1. Gypsum application reduces soluble Phosphorus (P) losses to the environment from poultry litter applications. There are growing concerns regarding the fate of nutrients, especially P, from land application of animal waste. One approach to reduce runoff losses of P is to treat manure or the soil receiving manure with chemical amendments such as gypsum. A study using rainfall simulations to examine the impact of flue gas desulfurization (FGD) gypsum application on runoff nutrient losses on a Coastal Plains soil. Four rates of FGD gypsum (0, 2.2, 4.4, and 8.9 Mg ha-1) were applied to plots of coastal bermudagrass, which had received application of 13.4 Mg ha-1 poultry litter. Plots with FGD gypsum but no poultry litter and plots with no litter or FGD gypsum were also utilized. Rainfall simulation was used to generate water runoff for 60 min and samples were analyzed for dissolved reactive P (SRP) and other total and soluble elements. Heavy metals were also analyzed. Results indicated a 51% reduction in total SRP load with the application of 8.9 Mg ha-1 FGD gypsum. Measurement of heavy metals in runoff where all found to be below detection limits. The results indicate that use of FGD gypsum on pastures receiving poultry litter in the Coastal Plains would be an effective method of reducing SRP losses to the environment.
2. Long term tillage and cropping system study reveals benefits to poultry litter applications. To develop effective conservation agriculture systems, cropping systems need to be evaluated over long time periods. Studies were conducted to evaluated cropping sequences of corn, soybean, and corn soybean rotations with wheat covers in conventional, strip, and no-tillage systems, following poultry litter additions to wheat cover over a ten year period. The study was conducted from 1991 to 2001 on a sandy loam soil. Wheat received either poultry litter or equivalent inorganic Nitrogen (N). Corn was fertilized with inorganic fertilizer in spring, while soybeans receive no fertilizer. Corn yields were influenced by tillage but soybean yields were not. Crop rotations significantly impacted soybean yield in 1992, 1995, and 1998, with higher yields observed in 1992, and 1995, and lower yields in 1998. Poultry litter significantly increased soybean yield eight of the nine years evaluated. This study suggests that poultry litter use for these crop rotations in conservation tillage systems could increase sustainable yield production.
3. Effects of poultry litter application on greenhouse gas emissions studied. Concentrations of greenhouse gases in the atmosphere have been increasing since pre-industrial times. Integrating poultry litter use into conservation agricultural systems could be a management practice for sequestering atmospheric Carbon (C) in soil. However, consideration for the best method for this management practice must be taken into account when applying poultry litter to maximize nutrient uptake and prevent gaseous loss in the form of Carbon Dioxide (CO2), Methane (CH4), and Nitrogen Oxide (N2O). Research was conducted studying the interaction of poultry litter application and tillage systems on greenhouse gas emissions. In addition, a literature review was published demonstrating the impact of poultry litter application in agricultural systems on C sequestration. Within this review, an evaluation of how poultry litter application practices affect gaseous flux of CO2, CH4, and N2O is discussed.
4. Effects of poultry litter handling and soil amendments impact on Nitrogen (N) mineralization studied. Recent changes in how poultry litter is removed from broiler houses as well as the increased use of chemical amendments to control environmental loss may affect N mineralization in soil and therefore N supply to crops. Laboratory study investigated whether gypsum, lime, aluminum sulfate or ferrous sulfate amendments used in conjunction with poultry litter cake, poultry litter cleanout, and bedding material would affect N release when amended to soil. The greatest N release was observed with poultry litter cake, followed by the cleanout, and bedding material. This implies that N release from poultry litter sources were most likely due to the percentage bird droppings in the litter. The use of chemical amendment aluminum sulfate generally decreased N supply when added to the poultry litter sources during this short-term study.
5. New garbage processing technology provides soil additive for effective degraded land reclamation. To reduce the amount of municipal solid waste being landfilled, a new garbage processing technology has been developed. This technology sterilizes and separates the municipal solid waste into recyclables (metals and plastics) and an organic material called Fluff®. The Fluff® material could be land applied to improve soil conditions. The U.S. Army often has large areas that have been damaged due to extensive army training and insufficient topsoil, organic matter, and nutrients necessary for successful revegetation. The potential of using the cellulose pulp as a soil amendment on these damaged training grounds was evaluated. Studies were conducted at Fort Campbell, KY, and Fort Benning, GA, to evaluate the end product as a soil amendment. Native grass establishment was successful with the use of Fluff®, with benefits observed five years after Fluff® application. Fluff® addition to soil also decreased compaction of the soil and increased soil Carbon (C) and Nitrogen (N) concentrations. This study showed that Fluff® could be used as an alternative to the current waste management practices for reclamation of degraded land.
6. Trash tree, Eastern red cedar, found to be effective potting media substrate replacement for pine bark for greenhouse production. Peat and perlite have served as industry standards in greenhouse substrates for over 50 years. Expanded perlite has long been used as an amendment in container mediums because of its ability to add air space to container substrates without adding to bulk density or affecting substrate pH and electrical conductivity (EC). However, due to increased restrictions on the harvesting of peat, as well as fluctuations in fuel prices necessary for shipping, the future availability of peat is a largely unknown factor in greenhouse production. Additionally, growers consider perlite to be a general nuisance due to the lung and eye irritation problems. These studies evaluated three possible substrate alternatives for use in greenhouse products, fresh sweetgum, hickory, and eastern redcedar. Three greenhouse annual crops (petunia, impatiens, and vinca) were planted in varying ratios of these three wood species mixed with peat. Plants grown with sweetgum and hickory as amendments did not perform as well as a traditional peat:perlite mix with respect to flower number and growth indices. However, plants grown in red cedar tended to be equivalent to those grown in a traditional mix. Data showed that greenhouse producers could amend their standard greenhouse substrate with up to 50% eastern red cedar with little to no differences in plant growth and overall aesthetic quality.
Torbert III, H.A., Polley, H.W., Johnson, H.B. 2012. Nitrogen and carbon cycling in a grassland community ecosystem as affected by elevated atmospheric CO2. International Journal of Agronomy. Article ID 817343, 5 pages, 2012. doi:10.1155/2012/817343.