毛叶苕子与燕麦混播对作物产量、土壤酶活性和微生物群落的影响

The effects of mixed sowing of hairy vetch and oat on crop yield,soil enzyme activity and microbial communities

【目的】探究内蒙古阴山北麓农业旱作区不同比例毛叶苕子与燕麦混播对作物产量、土壤酶活性和土壤微生物群落的影响。【方法】以毛叶苕子和燕麦为试验对象,设置单播毛叶苕子(DB1)、单播燕麦(DB2)、80%毛叶苕子+20%燕麦(HB1)、60%毛叶苕子+40%燕麦(HB2)、40%毛叶苕子+60%燕麦(HB3)、20%毛叶苕子+80%燕麦(HB3)6个处理,分别在生育前期、生育中期、生育后期采集0~20、20~40 cm土层样品,分析不同混播处理对作物产量和土壤酶活性以及微生物量碳、氮含量的影响;采用高通量测序技术,分析土壤微生物群落多样性和结构的变化。【结果】HB1、HB2、HB3处理较DB1处理毛叶苕子相对籽粒产量提高1%~11%,较DB2处理燕麦相对籽粒产量提高3%~25%。0~20 cm土层下生育中期,与DB1和DB2处理相比,HB2处理土壤过氧化氢酶活性显著提高9.65%和11.55%(P<0.05)、蔗糖酶活性显著提高11.47%和15.44%(P<0.05),HB1处理脲酶活性提高8.07%和19.41%(P<0.05);HB2处理微生物量碳含量、HB1处理微生物量氮含量均最高,分别为95.79、21.02 mg/kg。与DB2处理相比,HB2处理土壤细菌OTU指数显著增加15.79%(P<0.05)、Shannon指数增加5.41%;与DB1处理相比,HB2处理真菌OTU指数增加33.58%(P<0.05)、Shannon指数增加36.50%、Chao1指数增加6.56%。在门水平上,HB2处理提高了变形菌门(Proteobacteria)、绿弯菌门(Chloroflexi)、被孢菌门(Mortierellomycota)的相对丰度,同时降低了放线菌门(Actinobacteriota)、酸杆菌门(Acidobacteriota)、子囊菌门(Ascomycota)、担子菌门(Basidiomycota)的相对丰度。【结论】60%毛叶苕子+40%燕麦混播处理为内蒙古阴山北麓农业旱作区较适宜的混播比例,该处理下作物籽粒产量最高,土壤酶活性与微生物量碳、氮含量较高,土壤细菌和真菌多样性、丰富度与有益菌门的相对丰度均有所提高。

【Objective】To investigate the effects of different mixed sowing proportions of hairy vetch and oat on crop yield,soil enzyme activity and microbial communities in the agricultural dry-crop areas at the northern foothills of the Yinshan Mountains in Inner Mongolia.【Methods】Using hairy vetch and oat as experimental objects,six treatments were set up,namely,single sowing of hairy vetch(DB1),single sowing of oat(DB2),80%hairy vetch+20%oat(HB1),60%hairy vetch+40%oat(HB2),40%hairy vetch+60%oat(HB3),and 20%hairy vetch+80%oat(HB3).Soil samples were collected from the 0-20 and 20-40 cm soil layers in the early,middle,and late stages of growth,respectively.The effects on crop yield,soil enzyme activity and microbial biomass carbon and nitrogen content were analyzed,and changes in soil microbial community diversity and structure were analyzed by using high-throughput sequencing technology.【Results】HB1,HB2,HB3 treatments were 1%-11%higher than DB1 treatment for the relative grain yield of hairy vetch,and 3%-25%higher than DB2 treatment for the relative grain yield of oat.During the mid growth stage in the 0-20 cm soil layer,compared with DB1 and DB2 treatments,HB2 treatment soil catalase activity significantly increased by 9.65%and 11.55%(P<0.05),respectively,and sucrase activity significantly increased by 11.47%and 15.44%(P<0.05),HB1 treatment increased urease activity by 8.07%and 19.41%(P<0.05),respectively;HB2 treatment had the highest microbial biomass carbon content,while HB1 treatment had the highest microbial biomass nitrogen content,at 95.79 and 21.02 mg/kg,respectively.Compared with the DB2 treatment,the HB2 treatment soil bacterial OTU index was significantly increased by 15.79%(P<0.05),the Shannon index increased by 5.41%;Compared with DB1 treatment,HB2 treatment increased fungal OTU index by 33.58%(P<0.05),Shannon index increased by 36.50%,and Chao1 index increased by 6.56%.At the phylum level,HB2 treatment increased the relative abundance of Proteobacteria,Chloroflexi,and Mortierellomycota,while decreasing the relative abundance of Actinobacteriota,Acidobacteriota,Ascomycota,and Basidiomycota.【Conclusion】The mixed sowing treatment of 60%hairy vetch+40%oat is a suitable proportion for agricultural dry-crop areas in the northern foothills of Yinshan Mountains,Inner Mongolia.Under this treatment,crop grain yield is the highest,soil enzyme activity and microbial biomass carbon and nitrogen content are higher,and soil bacterial and fungal diversity,richness,and relative abundance of beneficial bacterial phyla are all increased.