苜蓿种植对矿山荒漠土微生物群落、酶活性及养分的影响

Effect of planting Medicago sativa on microbial communities,enzyme activity and nutrients in mine desert

为了探究苜蓿种植对矿山荒漠土的改良效应,采用16S rRNA高通量测序、冗余分析(RDA)和相关性分析等方法,分析未种植苜蓿(M0)、种植苜蓿4 a(M4)和5 a(M5)矿山荒漠土的微生物群落特征、酶活性及养分含量等.结果表明:(1) 3种处理下土壤的微生物Sobs、Chao指数由小到大为M0<M5<M4,M5的Shannon指数最低、Simpson指数最高;M4和M5的优势菌门是放线菌门、变形菌门和绿弯菌门,M0的优势菌门是放线菌门和绿弯菌门.(2)种植苜蓿后的矿山荒漠土碱性磷酸酶和脲酶活性增强,过氧化氢酶和蔗糖酶活性减弱;碱解氮、有效磷、速效钾和有机质含量由小到大依次为M0 <M5 <M4.(3)种植苜蓿后土壤中放线菌门和绿弯菌门丰度降低,且与养分含量呈负相关,而变形菌门丰度增加,且与养分含量呈正相关;酸杆菌门相对丰度升高,拟杆菌门相对丰度降低;参与化能异养、光能自养及碳、氮循环过程的代谢细菌丰度增加.综上,种植苜蓿可以增加矿山荒漠土的细菌总量、改变优势菌门丰度、增强细菌代谢功能,从而有效提高土壤质量.

To explore the effectiveness of Medicago sativa(alfalfa)cultivation on the improvement of desert mine soils,the mi-crobial community characteristics,enzyme activities,and nutrient contents of mining desert soils in areas with no alfalfa plant-ing(MO)and those that had been planted for four years(M4)and five years(M5)were analyzed by 16S rRNA high-throughput sequencing,redundancy analysis(RDA),correlation analysis,and other methods.The results showed that:The Sobs and Chao indices of soil microorganisms in the three groups were ranked as MO<M5<M4,with M5 having the lowest Shannon index and the highest Simpson index.①The dominant phyla in the M4 and M5 conditions were Actinobacteria,Proteobacteria,and Chloroflexi,while Actinobacteria and Chloroflexi dominated in Mo.②Affer alfalfa planting,the activities of alkaline phosphatase and urease in the soil increased,while those of catalase and sucrase decreased.The soil contents of alkalinehy-drolyzed nitrogen,available phosphorus,available potassium,and organic matter were ranked as M0<M5<M4.③The abun-dance of both Actinobacteria and Chloroflexi was reduced after alfalfa planting and was negatively correlated with nutrients,while the abundance of Proteobacteria increased and was positively correlated with nutrients.The abundance of Acidobacte-ria was increased,together with reduced relative abundance of Bacteroidetes.The abundance of metabolic bacteria involved in heterotrophic and photoautotrophic functions,as well as carbon and nitrogen cycling,was raised.In conclusion,planting alfal-fa can increase the bacterial contents in desert mine soils,together with altering the abundance of the dominant bacterial phyla,enhancing the metabolic functions of the bacteria,thereby effectively improving the soil quality.