The conversion of rainforests to plantations leads to about 50% loss in the organic carbon (C) content of the soil and strongly influences nitrogen (N) cycling, potentially increasing greenhouse gas emissions. However, the effect of land-use change in forests on the microbial communities responsible for C and N cycling processes remains poorly understood. This study quantified C and N fractions of soil organic matter in a tropical forest, rubber agroforestry system, 5- and 15-year-old rubber plantations. The community structure and abundance of fungi and bacteria were studied using high-throughput sequencing and q-PCR. Forest conversion substantially altered community structure and abundance of microbial communities. Rainforest conversion to plantation enhanced bacterial diversity and reduced the soil C mineralization rate. In addition, land-use change also enhanced the soil N mineralization rate in 5-year-old rubber plantation and agroforestry system. A structural equation modelling suggested that soil microbial communities played more dominant roles in driving the shift in C and N cycles caused by land-use change than soil C and N pools. These mechanistic insights into the differential control of soil fungal and bacterial communities on C and N mineralization has implications for managing land-use changes in tropical forest ecosystems.

雨林向人工林的转化导致土壤有机碳（C）含量减少约50％，并强烈影响氮（N）循环，从而可能增加温室气体排放。但是，人们对森林土地利用变化对造成碳和氮循环过程的微生物群落的影响知之甚少。这项研究量化了热带森林，橡胶农林业系统，5岁和15岁橡胶种植园中土壤有机质的C和N含量。使用高通量测序和q-PCR研究了真菌和细菌的群落结构和丰度。森林转化极大地改变了群落结构和微生物群落的数量。雨林转变为人工林可增加细菌多样性并降低土壤碳的矿化率。此外，土地用途的变化还提高了5年生橡胶林和农林业系统中土壤的氮矿化率。结构方程模型表明，土壤微生物群落在驱动由土地利用变化引起的碳和氮循环变化方面起着比土壤碳和氮库更重要的作用。这些对C和N矿化对土壤真菌和细菌群落的差异控制的机制见解对管理热带森林生态系统中的土地利用变化具有影响。