稻虾共作模式对稻田土壤细菌群落结构与多样性的影响

通过研究稻虾共作模式下0 ~ 60 cm土层土壤细菌群落结构与多样性，明确该模式下稻田土壤细菌的群落特征，旨在为研究稻虾共作模式下稻田土壤养分循环提供理论依据。依托湖北省潜江市白鹭湖农场15年定位试验，采集0 ~ 10 cm、10 ~ 20 cm、20 ~ 30 cm、30 ~ 40 cm、40 ~ 50 cm和50 ~ 60 cm土层土样，采用高通量测序技术分析土壤细菌群落结构和多样性，并研究土壤细菌群落特征与土壤理化性状的关系。与中稻单作模式相比，长期稻虾共作模式显著提高了0 ~ 10 cm和20 ~ 40 cm土层有机碳（TOC）含量、0 ~ 30 cm土层全氮（TN）含量、0 ~ 20 cm和30 ~ 40 cm土层全磷（TP）含量以及10 ~ 40 cm土层有效钾（AK）含量。长期稻虾共作模式后土壤细菌的群落组成发生了改变，显著提高了土壤中绿弯菌门、拟杆菌门、硝化螺旋菌门和芽单胞菌门的相对丰度，降低了蓝细菌门、放线菌门和疣微菌门的相对丰度；同时，稻虾共作模式显著提高了10 ~ 20 cm和30 ~ 50 cm土层细菌的物种丰富度和多样性，但降低了0 ~ 10 cm土层细菌的丰富度。相关性分析表明，TOC、TN、AP和AK是影响稻虾共作模式土壤中细菌群落结构及多样性的主要因素。长期稻虾共作模式改变了稻田土壤理化性状，改变了土壤细菌的群落组成，提高了深层土壤的细菌物种丰富度和多样性。

Effect of Rice-Crayfish Integrated System on Soil Bacterial Community Structure and Diversity in Paddy Field

In order to investigate the structure and diversity of soil bacterial community in 0-60 cm soil layers under rice-crayfish integrated system, the characteristics of soil bacterial community in paddy field were examined to provide theoretical basis for studying soil nutrient cycling in paddy field under this system. Soil samples in the soil layers of 0~10 cm, 10~20 cm, 20~30 cm, 30~40 cm, 40~50 cm and 50~60 cm were collected at a 15-year continuous location experiment in Bailuhu Farm of Qianjiang City of Hubei Province. The structure and diversity of soil bacterial community were analyzed by high-throughput sequencing technique, and the relationship between soil bacterial community characteristics and soil physicochemical properties was studied. The results showed that compared with the mid-season rice monoculture system, the long-term integrated rice-crayfish system significantly increased the contents of soil organic carbon, total nitrogen, total phosphorus and available potassium in the soil layers of 0~10 cm and 20~40 cm, 0~30 cm, 0~20 cm and 30~40 cm, and 10~40 cm, respectively. The long-term rice-crayfish integrated system changed the community composition of soil bacteria, significantly increasing the relative abundance of Chloroflexi, Bacteroidetes, Nitrospirae and Gemmatimonadetes, and decreasing that of Cyanobacteria, Actinobacteria and Verrucomicrobia. The long-term rice-crayfish integrated system significantly increased the species richness and diversity of bacteria in 10~20 cm and 30~50 cm soil layers, and decreased the richness of bacteria in 0~10 cm soil layers. The correlation analysis showed that organic carbon, total nitrogen, available phosphorus and available potassium were the main factors affecting the bacterial community structure and diversity in the rice-crayfish integrated system. In general, the long-term rice-crayfish integrated system changed the physical and chemical properties of paddy soil and the composition of soil bacterial community, and improved the richness and diversity of bacterial species in deep soil.