Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/18/2014
Publication Date: 3/11/2015
Publication URL: http://handle.nal.usda.gov/10113/60925
Citation: Adeli, A., Sheng, J., Jenkins, J.N., Feng, G.G. 2015. Composting and gypsum amendment of broiler litter to reduce nutrient leaching loss. Journal of Environmental Quality. 44:676-683.
Interpretive Summary: In recent years, significant declines in soil organic matter content and cation-exchange capacity due to removal of plant biomass in crop production have become common problems in areas of intensive agriculture. Since poultry production is a major industry in the southeastern USA, the use of poultry litter (a mixture of manure and bedding materials) as a fertilizer for row crop production can enable addition of large amounts of carbon and nutrients back into soil to improve its quality. However, environmental nutrient pollution may also result if poultry litter applied in excess of plant needs. The over-use of fresh manures which has low C/N ratios and large quantities of readily mineralizable N, on vulnerable soils can cause both soil pollution and eutrophication of freshwater lakes and streams due to influx of nutrients by runoff and leaching from the soil. Composting provides one potential method for stabilizing nutrient levels in litter. The combination of materials with high and low C/N ratios accelerates microbial transformation of labile organic compounds into a more stable, humus-like material during composting. Compost is less prone to rapid mineralization and nutrient leaching than fresh litter, and it effectively creates a pool of slow-release nutrients when applied to soil. Although numerous studies have involved the use of poultry litter as a fertilizer and potential litter derived-nutrient dynamics in the ecosystem, however, the effect of composted litter relative to fresh litter on leaching losses of nutrients has not been well documented. The objectives of this study was to compare the potential nutrient leaching losses from fresh and composted litter and evaluate the effects nutrient immobilizing agent (FGD gypsum) on leaching losses of nutrients.
Technical Abstract: Relative to fresh broiler litter, little is known about the dynamics of composted litter derived-nutrient in the ecosystem. In this study, the potential leaching losses of nutrients from compost relative to fresh broiler litter along with flue gas desulfurization (FGD gypsum), as a nutrient immobilizing agent, was investigated. Undisturbed soil columns from a natural sod of bermudagrass (Cynodon dactylon L.) established in a Marietta silt loam soil was taken. Columns were treated with fresh and composted litter in the presence or absence of FGD gypsum. Columns were periodically leached and biomass was harvested during the 60-day period experiment. Quantities of fresh and composted litter added to the soil columns was based on N needs of bermudagrass as determined from total N content of litter and compost. Both fresh and composted litter were applied to bermudagrass at similar rates. Total N rate applied to bermudagrass was 450 kg ha-1. Gypsum was applied with litter and compost at the rate based on 20% of litter weight. Cumulative amounts of P, K, Cu, and Zn in leachate from soil amended with compost were 51%, 45%, 40% and 40% less than those amended with fresh litter, respectively. Amendment with fresh litter only resulted in the largest leaching of NO3-N (8.8 mg per column), whereas nitrate leaching from compost amended soil was less than or equal to 2.3 mg per column. In addition, significant decreases in P and Zn in leachate from columns were observed when gypsum was added to fresh litter. Both forms of poultry litter increased bermudagrass growth compared with unamended soil, and gypsum application further increased yields when added to both litter and compost. Although composting poultry litter was most effective at limiting nutrient leaching, our results demonstrate that co-application of broiler litter with FGD gypsum may provide the most effective management option for minimizing leaching losses of nutrients while sustaining crop productivity.