Changes in microbiota and functional properties in anthropogenic soil

Since 1993, when Muyzer et al., used denaturing gradient gel electrophoresis (DGGE) to detect environmental soil microbial community for the very first time, it opened a brand-new page for soil microbial ecologist. He offered us an opportunity to explore the unculturable microorganisms which accounted for above 90% lived in soil. More and more scientists concerned this subject about soil health and function of soil microorganisms, not only because the microorganisms played key roles in many soil biochemical elements cycling but also understanding their working mechanisms will help us to build a sustainable soil ecosystem in this full of limited resources planet. This thesis is focused on the differently managed soil that how the soil quality changed and soil microbiota response to the different management. The main background of the Chapter 2 is the total organic carbon loss caused by the conversion of rainforests into agricultural plantations. The main background of Chapter 3 and 4 is returning something back to the soil, such as composts and pyrogenic organic matter. So, in both cases the total organic carbon is increased. In all the cases, we focused on soil properties, bacteria community, fungi community, their interrelationships, and consequences. The results obtained in this thesis, first, it will provide a mechanistic understanding of carbon and nitrogen losses from the conversion of rainforests to agricultural plantations and the roles of microbial communities in the decomposition of soil organic matter and nitrogen cycling. Secondly, we will understand better the relative importance of biotic and abiotic factors who contribute more to soil respiration after different nitrogen sources addition. Thirdly, we could expand our knowledge about long-term large charcoal addition to soil impact on soil environment and soil microbial community and gain a valuable model for biochar ageing effect in soil.