不同节水稻作模式对土壤微生物数量和微生物量碳氮的影响

Effects of Water-saving Modes for Rice Cultivation on Soil Microbial Quantity and Microbial Biomass C and N Contents

针对南方丘陵区季节性干旱这一区域问题,以节水稻作模式为研究对象,以常规稻作模式为对照,通过田间定位试验,研究了稻基农田土壤微生物数量和土壤微生物量碳氮的变化规律。结果表明,与该区常规稻作模式相比,节水稻作模式的土壤微生物数量和土壤微生物量碳氮差异显著;节水稻作模式有利于土壤细菌和放线菌的增殖,但抑制了真菌的增殖;土壤微生物量碳和微生物量氮的显著增加,以水旱轮作双季稻模式最佳,说明采用节水稻作模式可有效提升土壤细菌数量、放线菌数量、微生物量碳和微生物量氮含量。因此,在南方丘陵季节性干旱区,采用节水稻作模式,可促进稻田生态系统健康持续发展。

The water-sa drought problem in the ving rice cultivation（WSRC） modes are good strategies dealing with the seasonal hilly region of southern China. Few studies were conducted to address the effects of these practices on soil microbial communities. This study aims to assess the effect of WSRC practice on soil microbial quantity, soil microbial biomass C（SMB-C） and soil microbial biomass N（SMB-N） in a field experi- ment. The results showed that significantly differences were observed between water-saving cultivation and conventional double cropping in terms of both soil microbial quantity and soil microbial biomasses. Compared with conventional practice, the implementation of WSRC accelerated the proliferation o{ soil bacteria and ac- tinomycetes, reduced the proliferation of fungi, and increased SMB-C and SMB-N. The greatest number o~ soil bacteria and actinomycetes and the highest contents of SMB-C and SMB-N were found in double cropping with flood-drought rotation in comparison of other WSRC practices. We concluded that WSRC practices are of great significance for the sustainability of rice cultivation by stimulating soil microbial activities.