亏缺灌溉对河套灌区向日葵土壤微生物群落结构多样性的影响

Effects of deficit irrigation on soil microbial community structure diversity of sunflower in Hetao Irrigation District

为明确亏缺灌溉对向日葵生育期内土壤微生物群落的影响,在河套灌区开展田间试验.以当地灌水水平为对照CK(330 mm),设置2个水分亏缺处理:轻度水分亏缺W1(210 mm)和重度水分亏缺W2(120 mm),分析亏缺灌溉对向日葵各生育期土壤表层(0~20 cm)微生物群落和理化性质的影响,并揭示土壤微生物与理化性质的内在联系.结果表明:处理W1提高了土壤微生物多样性及土壤细菌中变形菌门、绿弯菌门、酸杆菌门、真菌中被孢霉门等优势菌门的相对丰度.与CK相比,W1的土壤pH值平均降低了0.13,温度和硝态氮质量比分别平均提高了1.44℃和14.2%.Pearson相关性分析表明土壤含水率、温度、pH,EC、硝态氮是影响细菌多样性的主要因子;温度、铵态氮和硝态氮是影响真菌多样性的主要因子.冗余分析表明土壤含水率、EC和温度是影响细菌群落结构的主要因子;含水率、EC和铵态氮是影响真菌群落结构的主要因子.综上,轻度水分亏缺(W1)是适宜微生物生长的水分条件.

In order to clarify the effect of deficit irrigation on soil microbial communities during the growth period of sunflowers,field experiments were carried out in Hetao Irrigation District.The local irrigation level was taken as the control(330 mm,CK),set mild water deficit(210 mm,W1)and severe water deficit(120 mm,W2).The effects of deficit irrigation on soil microbial community and physicochemical properties in the surface layer(0-20 cm)at different growth stages of sunflower were analyzed,and the internal relationship between soil microbe and physicochemical properties was revealed.The results show that the treatment of W1 increases soil microbial diversity and the relative abundance of dominant phyla,such as Proteobacteria,Chloroflexi and Acidobacteria in bacteria,and Mortierellomycota in fungi.Compared with CK,the soil pH value decreases by an average of 0.13 units,temperature and nitrate nitrogen content increase by an average of 1.44℃and 14.2%,respectively.Pearson correlation analysis shows that soil water content,temperature,pH,EC and nitrate nitrogen are the key factors affecting bacterial diversity.The temperature,ammonium nitrogen and nitrate nitrogen are the key factors affecting fungal diversity.Redundancy analysis shows that soil water content,EC and temperature are the main important factors affecting bacterial community structure.The soil water content,EC and ammonium nitrogen are the main important factors affecting fungal community structure.In summary,mild water deficit(W1)is the suitable water condition for microbial growth.