Objective  The distribution characteristics of soil microbial groups were revealed in arid and semi-arid areas, in order to provide theoretical support for the construction of the technology model of straw mulching and no tillage sowing in rain cultivation area of West Liaohe plain.

  Method  Five treatments were set up: no-tillage with shallow rotation (CK) , straw mulching in autumn and no-tillage in spring (MG) , no-tillage with straw mulching in autumn and secondary crushing in spring (ME) , no-tillage with straw mulching in autumn and application of saprophyte in spring(MF) , and no-tillage with straw mulching in autumn and straw secondary crushing application of saprophyte in spring (EF), the effects of different ways of returning straw to soil on soil microorganism were studied.

  Result  The results showed that the number of operational taxonomic unit (OTU) was decreased by returning straw to soil in 0-15 cm soil layer. The number of OTU of MF and EF bacteria in 15-30 cm soil layer was higher, the relative abundance rates of Arthrobacter, Gemmatimonas and Sphingomonas in MF was increased, the relative abundance rates of Haliangium, Lysobacter, Subgroup_10, Alistes and Bacteroides in EF were increased. The numbers of bacteria OTU, Arthrobacter, Bacteroidetes, Gaiella and Nitrispira were increased, but the relative abundance rates of Alistes and Escherichia-shigella were decreased in 30-45 cm soil layer. Straw returning reduced the number of soil fungi OTU in surface soil (0-15 cm), but increased the number of OTU in 15-45 cm soil. Straw returning reduced the relative abundance rates of Exophiala and Mortierella. Podospora, Ceratobasidium and Archaeorhizomyces appeared in straw returning. Entoloma and Schizomyceum appeared in the application of ripening agent, and increased the relative abundance rates of Schizomyceum. There were more bacteria than fungi that could have a great impact on the environment in the test area. In terms of bacterial diversity, the relative abundance rates of Flavobacterium, Ruminococcus_gnavus_group, Methylophilaceae were increased after no tillage returned straw to the field and decomposition agent. ME and EF increased the relative abundance rates of Flavobacterium and Methylophilaceae significantly. In terms of fungal diversity, the relative abundance rate of Mrakia and Myceliophthera in CK was higher, the relative abundance rates of Peristomalis and Powellomyces in MF was higher, and the relative abundance rates of Cercophora and Scytalidium species in EF was higher.

  Conclusion  The patterns of no-tillage straw returning to the field in autumn and spring with secondary crushing and application of decomposing agents can increase the diversity and relative abundance of cellulose-degrading functional bacteria and mycorrhizal fungi, which plays a positive role in improving the soil microbial diversity and richness of spring maize field in the rain-fed area of West Liaohe plain.