|Torbert, Henry - Allen|
Submitted to: Soil Biology and Biochemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/20/2006
Publication Date: 12/26/2006
Citation: Busby, R.R., Torbert III, H.A., Gebhart, D.L. 2006. Carbon and nitrogen mineralization of non-composted and composted municipal solid waste in sandy soils. Soil Biology and Biochemistry. 39:1277-1283. Interpretive Summary: A new garbage processing technology has been developed that sterilizes and separates inorganic and organic components of municipal solid waste. In this study, the organic byproduct of this process, named Fluff®, was evaluated as a potential soil amendment. A incubation study was conducted to compare the changes of this new product with mature municipal waste compost. These waste products were added to two soils at different rates to determine potential impact the materials may have on soil carbon and nitrogen levels. Results form the study indicate that the Fluff material may be best suited for highly degraded soils, low in organic matter where restoration of vegetation adapted to nutrient poor soils is desired.
Technical Abstract: A sterilized, but undecomposed, organic byproduct of municipal waste processing was incubated in sandy soils to compare C and N mineralization with mature municipal waste compost. Waste products were added to two soils at rates of 17.9, 35.8, 71.6, and 143 Mg/ha dry weight and incubated at 25°C for 90 days. Every 30 days, NO3 and NH4 concentrations were analyzed and C mineralization was measured as total CO2-C evolved and percent of additive total organic C. Carbon mineralization of the undecomposed waste decreased over time, was directly related to application rate and soil nutrient status, and was significantly higher than C mineralization of the compost, which maintained a constant C evolution rate across time, soils, and application rates. Carbon mineralization measured as percent C added by the wastes also indicated no differences between composted waste treatments. However, percent mineralization of C added in the undecomposed waste treatments was inversely related to application rate in the more productive soil, and no rate differences were observed in the highly degraded soil. Total inorganic N concentrations were considerably higher in the compost- and un-amended soils than in undecomposed waste treatments. Significant N immobilization occurred in all undecomposed waste treatments. Because C mineralization of the undecomposed waste was dependant on soil nutrient status and led to significant immobilization of N, this material appears to be best suited for highly degraded soils low in organic matter where restoration of vegetation adapted to nutrient poor soils is desired.