Modeling C and N mineralization during decomposition of anaerobically digested and composted municipal solid waste

Summary

Application of municipal solid waste (MSW) to arable land can be used to close the nutrient cycle between urban and rural areas. The aim of the current study was to quantify net N mineralization and respiration from composted MSW (CMSW) and anaerobically digested MSW (ADMSW) applied to soil, and to test, whether a simple relationship between net N mineralization and respiration developed for plant materials, was applicable for these MSW’s. In a laboratory experiment, CMSW and ADMSW were incorporated into soil and incubated at 15 °C. During the 149 day experiment, net N mineralization and respiration was determined. Cumulated respiration derived from the MSW’s was very steep during the first 30 days, after which the cumulated respiration leveled off. However, calculated on the basis of applied C, the ADMSW was 10 times more degradable then the CMSW. Both MSW’s caused an initial net N immobilization followed by a re-mineralization. A simple model based on the relationship between net N mineralization and respiration, was only applicable for the MSW’s, after significant modifications. If farmers 2 should recognize CMSW and ADMSW, as valuable fertilizers, it is important that these can be produced with a higher maturity, in order to avoid initial immobilization.