Principal component analysis of straw-decomposing microbial communities based on the results of PLFA, CLPP, and DGGE. Average loading scores along the first and second principal components were shown with standard errors from three repeats. Residue samples from different geographic sites and soils are differentiated by the shape and color of the symbols: Hailun (squares), Fengqiu (triangles), and Yingtan (circles), as well as black soil (black), Chao soil (brown), and red soil (red).