Water scarcity in arid and semiarid areas highlights the importance of developing water-saving irrigation techniques. Soil extracellular enzyme activities (EEAs) and microbes are important for soil biochemical cycles and plant growth. However, little is understood about how soil EEAs, and microbial communities respond to water-saving irrigation systems and levels. Therefore, a field experiment was carried out over four consecutive wheat-maize seasons to explore the effects of surface irrigation (SI) and drip irrigation (DI) coupled with different irrigation levels (i.e. 65, 50, 35 and 20 mm/event, represents sufficient, mild deficit, moderate deficit and serious deficit irrigation, respectively) on the plant biomass, soil properties, soil EEAs, and bacterial community. The results revealed that mild deficit irrigation showed no significant impact on plant biomass, serious and moderate deficit irrigation significantly decreased crop biomass by 49.0 % and 26.6 %, respectively, compared with sufficient irrigation. However, the crop biomass of serious and moderate deficit irrigation under DI were 15.4 % and 17.4 % higher, respectively, than that under SI. Serious and moderate deficit irrigation significantly increased soil available K accumulation and soil urease activity, decreased bacterial richness, and shifted the bacterial community structure. No significant differences were found between mild deficit and sufficient irrigation. The relative abundances of Firmicutes, Gemmatimonadota, and Myxococcota significantly increased under serious deficit irrigation, while Acidobacteriota significantly decreased. Moderate deficit irrigation under DI did not shift bacterial community structure, while under SI did. Soil pH, electrical conductivity (EC), available K, and plant biomass were the major factors influencing the bacterial community compositions. Serious deficit irrigation reduced the complexity and stability of the soil bacterial co-occurrence network. The network of DI had more significant interactions among bacteria than the SI. Therefore, DI coupled with moderate deficit irrigation is more beneficial to maintain crop yield and the stability of bacterial community structure than SI.

中文翻译：

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4个麦玉米轮作季节土壤微生物群落特征和酶活性对不同灌溉模式的响应


干旱和半干旱地区的缺水凸显了发展节水灌溉技术的重要性。土壤细胞外酶活性 （EEA） 和微生物对土壤生化循环和植物生长很重要。然而，人们对土壤 EEA 和微生物群落如何对节水灌溉系统和水平做出反应知之甚少。因此，在小麦-玉米连续四个季节进行了田间试验，探讨地表灌溉 （SI） 和滴灌 （DI） 耦合不同灌溉水平（即 65、50、35 和 20 mm/事件，分别代表充足、轻度赤字、中度赤字和重赤字灌溉）对植物生物量、土壤性质、土壤 EEA 的影响， 和细菌群落。结果表明，轻度亏缺灌溉对植物生物量没有显著影响，与充分灌溉相比，重度和中度亏缺灌显著降低了作物生物量，分别降低了 49.0 % 和 26.6 %。然而，DI 下重度和中度亏缺灌溉的作物生物量分别比 SI 下高 15.4 % 和 17.4 %。重度和中度亏缺灌溉显著增加了土壤速效钾积累和土壤脲酶活性，降低了细菌丰富度，并改变了细菌群落结构。轻度缺损和充分灌溉之间没有发现显著差异。厚壁菌门 （Firmicutes） 、 Gemmatimonadota 和 Myxococcota 的相对丰度在严重缺损灌溉下显著增加，而酸杆菌 （Acidobacteriota） 显著降低 DI 下中度缺损灌溉没有改变细菌群落结构，而在 SI 下则发生了改变。 土壤 pH 值、电导率 （EC） 、速效钾和植物生物量是影响细菌群落组成的主要因素。严重的亏缺灌溉降低了土壤细菌共生网络的复杂性和稳定性。DI 网络在细菌之间的相互作用比 SI 更显着。因此，DI 联合适度亏缺灌溉比 SI 更有利于维持作物产量和细菌群落结构的稳定性。