Effects of simulated acid rain on soil microbial biomass carbon and total organic carbon in a monsoon evergreen broadleaved forest at the Dinghushan Nature Reserve Effects of different straw-returning regimes on soil organic carbon and carbon pool management index in Guanzhong Plain, Northwest China Soil Particle Composition and Its Relationship with Nutrient Contents in a Quercus aquifolioides Forest at Different Altitudinal Gradient Study on the Active Organic Carbon in Soil under Different Types of Vegetation Short-term effects of different tillage modes combined with straw-returning on the soil labile organic carbon components in a farmland with rice-wheat double cropping.