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[目的]探讨保水剂不同施用量对杨树土壤物理性状与微生物活性的作用效果,为中国杨树人工林节水高产实践模式提供理论依据与技术参考。[方法]研究CK(常规灌量)、CL(60%常规灌量配施10g保水剂)、CM(60%常规灌量配施30g保水剂)和CH(60%常规灌量配施50g保水剂)4个处理对杨树苗土壤物理性状、水稳性团粒结构、微生物数量、微生物呼吸和代谢熵的影响。[结果]同CK相比,CM处理显著降低了土壤容重,并明显提高了非毛管孔隙度,其中土壤容重分别较CK,CL和CH处理显著下降13.71%,5.31%和7.76%;还明显促进了土壤大团聚体(>0.25mm团粒)的形成。同时,CM处理明显增加了土壤微生物总量和微生物量碳、氮含量,并显著增强了土壤微生物呼吸作用,其微生物呼吸速率分别比CK,CL和CH处理提高30.77%,11.84%和7.59%。此外,CM处理还降低了代谢熵,分别较CK,CL和CH处理下降4.81%,8.29%和9.74%。[结论]适宜的节水灌溉措施(60%常规灌量与30g保水剂组合)有助于改善杨树苗土壤的物理环境,并增强微生物活性。
[Objective] The research aimed to discuss the effects of different water-retaining agents on physical properties and microbial activities of poplar soil, and provide theoretical basis and technical reference for practical practices of water-saving and high-yield poplar plantation in China. [Method] The effects of CK (conventional irrigation), CL (60% normal irrigation with 10g super absorbent), CM (60% normal irrigation with 30g super absorbent) and CH (60% normal irrigation with 50g water retention) The effects of 4 treatments on soil physical properties, water stable aggregate structure, microbial population, respiration and metabolic entropy of microorganisms in poplar seedlings. [Result] Compared with CK, CM treatment significantly reduced soil bulk density and significantly increased non-capillary porosity. Soil bulk density decreased significantly by 13.71%, 5.31% and 7.76% compared with CK, CL and CH treatments, respectively, and significantly promoted The formation of large soil aggregates (> 0.25mm pellets). At the same time, CM treatment significantly increased soil microbial biomass carbon and nitrogen, and significantly enhanced respiration of soil microorganisms. The microbial respiration rate increased 30.77%, 11.84% and 7.59% higher than CK, CL and CH treatment, respectively. In addition, CM also reduced the metabolic entropy, which was 4.81%, 8.29% and 9.74% lower than that of CK, CL and CH, respectively. [Conclusion] The suitable water-saving irrigation measures (combination of 60% conventional irrigation and 30g water-holding agent) could help to improve the physical environment of poplar seedlings soil and enhance the microbial activity.