Spatial characters of soil microbial quantities and enzyme activity in coal mining subsided area

Key words: 
• coal mining /
• land subsidence /
• soil microbial quantities /
• enzyme activity /
• spatial variation

Abstract: Based on field investigation and sample analysis of mining soil from subsided land in Jiaozuo City Henan Province, microbial quantities and enzyme activities in different sites and layers were studied. The results showed that compared with the non-subsided land the distribution characters of soil microbial quantities, enzyme activities and compositional proportion in total soil microbe were remarkablely changed. In the surface (0～5 cm), upper(5～10 cm) and middle(10～20 cm)layers, the quantities of total microbe and bacteria in subsided land were significantly low, while the quantities of total microbe, bacteria, fungi and actinomycete in deep layer(20～40 cm) were significantly high. The proportion of bacteria in total microbe was respectively lower 20.64% and 13.17% than in contrast land in the surface and upper layers, while the proportion of actinomycete was respectively higher 20.69% and 12.66% than that. The activities of soil urease, sucrase, phoshatase, dehydrogenase, catalase and polyphenol oxidase in subsided land were respectively lower 1.5%, 17.5%, 22.0%, 35.3%, 20.4% and 5.4% than in contrast land in the surface layer. The spatial variations of soil microbial quantities and some enzyme activities in the subsided land were remarkable. Vertical distribution of the quantities of fungi, actinomycete and the activities of sucrase, phoshatase, dehydrogenase, catalase, polyphenol oxidase in subsided land were different from the contrast land. The results indicated that land subsidence in coal mining area induced the remarkable variation of soil microbial quantities and enzyme activities in the horizontal and vertical distribution, and it was the main reason that results in the farmland degradation and crop productivity depression.