冬灌制度对膜下滴灌棉田土壤理化性质、酶活性和微生物群落的影响

Effects of winter irrigation schedule on soil physicochemical properties,enzyme activities and microbial communities in cotton fields with drip irrigation under film

为明确不同冬灌制度的应用效果,以南疆膜下滴灌棉田为研究对象,选取每年冬灌处理(CK)、不冬灌处理(H1)及隔年冬灌处理(H2)3种冬灌制度,结合高通量测序技术对冬灌后土壤的理化性质、生物学性质以及微生物群落组成进行测定与分析。结果表明:(1)各处理间0~20 cm土层土壤总盐含量无显著差异,与CK相比,H1和H2处理显著降低了脲酶(0.96%~1.35%)和转化酶活性(1.17%)以及微生物量氮含量(4.21%~7.03%),但H2处理显著提高了土壤有机质(14.30%)、全氮(14.29%)、全磷(4.55%)和全钾(7.40%)含量;H1处理显著降低了土壤有机质(6.03%)、全磷(12.5%)和水分(23.08%)含量,提高了微生物量碳氮比(7.37%)。(2)不同处理下细菌群落的丰度和多样性以及真菌群落的丰度无显著差异,但与CK相比,H1和H2处理显著提高了真菌的辛普森指数(4.12%~4.55%)。此外,H1较CK处理提高了细菌放线菌门(Actinobacteria)、酸杆菌门(Acidobacteria)、绿弯菌门(Chloroflexi)和真菌担子菌门(Basidiomycota)的相对丰度,H2较CK处理提高了细菌变形菌门(Proteobacteria)、芽单胞菌门(Gemmatimonadetes)和真菌被孢霉门(Mortierellomycota)的相对丰度。(3)相关性分析结果表明细菌的群落结构主要受微生物量碳含量的影响,真菌的群落结构和多样性分别受转化酶和脲酶活性的影响。在无法保证每年冬灌用水的情况下,隔年冬灌更有利于保障膜下滴灌棉田的土壤耕地质量。

To investigate the impact of distinct winter irrigation strategies,we selected three winter irrigation regimes:the annual winter irrigation treatment(CK),the no winter irrigation treatment(H1),and the alternate year winter irrigation treatment(H2)for examination in cotton fields located in South Xinjiang,utilizing drip irrigation under membrane cover.By employing high-throughput sequencing technology,we assessed and analyzed the physicochemical and biological characteristics,as well as the composition of soil microbial communities after winter irrigation.The findings revealed that:(1)There were no substantial disparities in soil total salt within the 0~20 cm soil layer across the treatments.In comparison to the CK treatment,both the H1 and H2 treatments resulted in significant reductions in urease activity(0.96%~1.35%),invertase activity(1.17%),and microbial nitrogen content(4.21%~7.03%).Nevertheless,the H2 treatment notably increased soil organic matter content(14.30%),total nitrogen content(14.29%),total phosphorus content(4.55%),and total potassium content(7.40%).Conversely,the H1 treatment brought about a reduction in soil organic matter(6.03%),total phosphorus(12.5%),and moisture content(23.08%),and increased the microbial biomass carbon to nitrogen ratio(7.37%).(2)While there were no significant variations in the abundance and diversity of bacterial communities and the abundance of fungal communities among the treatments,both H1 and H2 treatments substantially augmented fungal diversity(4.12%~4.55%)compared to the CK treatment.Additionally,H1 elevated the relative abundance of bacterial Actinobacteria,Acidobacteria,Chloroflexi and fungal Basidiomycota when contrasted with the CK treatment,while H2 exhibited higher relative abundance in bacterial Proteobacteria,Gemmatimonadetes,and Mortierellomycota than the CK.(3)The results of correlation analysis revealed that microbiomes carbon content primarily influenced the community structure of bacteria,while the diversity of fungi was influenced by the activities of invertase and urease,respectively.In scenarios where consistent annual winter irrigation cannot be guaranteed,adopting a biennial winter irrigation approach appears more favorable for preserving soil quality in drip-irrigated cotton fields under the film.