Mulching is widely adopted in arid regions to improve soil environment and crop productivity. However, our understanding of the underlying mechanisms of such improvements from enzyme activity and rhizosphere microbial community structure perspectives remain poor. To fill the gap, soil zymography was coupled with high-throughput sequencing to investigate enzyme activities and bacterial community structure in a 10-year field experiment in a semi-arid region. We examined the effects of two mulching measures (plastic film mulching [FM] and straw mulching [SM], with no mulching as the control [CK]) on the maize rhizosphere extent of β-glucosidase and leucine aminopeptidase activities and the abundance of the bacterial genes encoding these two enzymes. The enzyme activity in the SM and FM measures was higher compared to the CK measures (P < 0.05). SM had higher influence than FM on β-glucosidase activity and its rhizosphere extent. This was related to the increase in soil organic carbon (SOC) content and the stable bacterial community structure and interactions under SM. In contrast, leucine aminopeptidase activity was the highest under FM due to the higher soil temperature and moisture content under FM which further intensified nutrient competition among microorganisms or between microorganisms and plants. In addition, Proteobacteria and Acidobacteria were the major contributors to β-glucosidase activity despite their genes encoding β-glucosidase not increasing under SM. Conversely, the copy number of genes encoding leucine aminopeptidase and the genes encoded by Proteobacteria (the main contributor) decreased under FM. Therefore, total gene number is not a stable indicator of microbial function (such as enzyme activity) and cannot explain enzyme activity adequately. Overall, this study establishes a connection between rhizosphere enzyme activity and bacterial communities, revealing the mechanisms by which changes in environmental nutrient supply and bacterial community composition under straw mulching and plastic film mulching measures lead to variations in enzyme efficiency.

干旱地区广泛采用覆盖来改善土壤环境和提高作物生产力。然而，我们从酶活性和根际微生物群落结构的角度对这种改善的潜在机制的理解仍然很差。为了填补这一空白，我们在半干旱地区进行了为期 10 年的田间实验，将土壤酶谱与高通量测序相结合，研究酶活性和细菌群落结构。我们研究了两种覆盖措施（地膜覆盖 [FM] 和秸秆覆盖 [SM]，不覆盖作为对照 [CK​​]）对玉米根际 β-葡萄糖苷酶和亮氨酸氨肽酶活性程度以及编码这两种酶的细菌基因。SM 和 FM 测量中的酶活性高于 CK 测量（ P < 0.05）。SM对β-葡萄糖苷酶活性及其根际范围的影响高于FM。这与SM下土壤有机碳（SOC）含量的增加以及稳定的细菌群落结构和相互作用有关。相反，FM下亮氨酸氨肽酶活性最高，因为FM下土壤温度和含水量较高，进一步加剧了微生物之间或微生物与植物之间的养分竞争。此外，变形菌门和酸杆菌门是β-葡萄糖苷酶活性的主要贡献者，尽管它们编码β-葡萄糖苷酶的基因在SM下没有增加。相反，FM 下编码亮氨酸氨肽酶的基因和变形菌（主要贡献者）编码的基因的拷贝数减少。因此，基因总数并不是微生物功能（如酶活性）的稳定指标，不能充分解释酶活性。总体而言，本研究建立了根际酶活性与细菌群落之间的联系，揭示了秸秆覆盖和地膜覆盖措施下环境养分供应和细菌群落组成的变化导致酶效率变化的机制。