Short-term effects of municipal solid waste compost amendments on soil carbon and nitrogen content, some enzyme activities and genetic diversity

Municipal solid waste (MSW) composts have been frequently used as N and C a mendments to improve soil quality and to support plant growth, with the add itional benefit of reducing waste disposal costs. However, attention has be en paid to the risks of MSW use for the soil environment. The presence of h eavy metals in MSW composts can affect some microbiological characteristics of soil such as the structure of the soil microbiota, which are responsibl e for the transformations making nutrients available to plants. The effects of MSW compost and mineral-N amendments in a 2-year field trial on some ph ysical-chemical properties, some enzyme activities and the genetic diversit y of cropped plots (sugar beet-wheat rotation) and uncropped plots were inv estigated. Variations of pH were not statistically related to MSW compost a nd mineral-N amendments, or to the presence of the crop. Amendment with MSW compost increased the organic C and total N contents, and dehydrogenase an d nitrate reductase activities of soil. In cropped plots amended with MSW c ompost, dehydrogenase activity was positively correlated with P-glucosidase activity, and both enzyme activities with organic C content. No MSW compos t dosage effect was detected. No effects were observed on denaturing gradie nt get electrophoresis and amplified rDNA restriction analysis patterns, in dicating that no significant change in the bacterial community occurred as a consequence of MSW amendment.