Plant residues play a crucial role in global carbon sequestration and climate change mitigation. Decomposition of plant residues is largely mediated by soil-dwelling microorganisms whose activities are influenced by both climate conditions and soil properties. However, a comprehensive understanding of their relative importance remains elusive, mainly because traditional methods, such as soil incubation and environmental surveys, have a limited ability to differentiate between the combined effects of climate and soil. Prof Sun led his group to build a large-scale reciprocal soil transplantation experiment in 2006, which includes red soil, Chao soil, and black soil, located in mid-subtropical, warm-temperate, and cold-temperate zones. Based on this research platform, they examined microbial communities associated with straw decomposition in three initially identical soils placed in parallel in three climate regions of China. Maize straws buried in mesh bags were sampled during 2 years and subjected to microbiological analyses (BIOLOG、PFLA、DGGE、16S rRNA clone library analysis). They found that location rather soil is the primary determining factor for the rate of straw decomposition and structures of the associated microbial communities. Their research results suggest that climate (specifically, geographic location) has stronger effects than soil on straw decomposition; moreover, the successive process of microbial communities in soils is slower than those in straw residues in response to climate changes. When fresh plant residues are released into the soil, the decomposing microbial community will experience a gradual shift of nutrient state from resource repletion in the early stages (as a result of a rapid degradation of labile substrates) to resource depletion in the late stages. We found that both Gammaproteobacteria and Alphaproteobacteria are copiotrophs. While Deltaproteobacteria and Acidobacteria behaved like oligotrophs with higher abundance in later stages or warmer regions.