摘要:本文通过区域调查采样和统计分析，探讨了川西平原土壤微生物生物量碳（MBC）、土壤微生物生物量氮（MBN）和土壤微生物生物量磷（MBP）含量特征及其对气候、海拔、母质和土地利用等因素的响应，揭示了其关键影响因素，以期为川西平原地区土壤质量管理提供参考。结果表明，不同土壤类型的MBC、MBN和MBP含量表现为冲积土显著高于水稻土、潮土和黄壤（P < 0.05），潮土MBC/MBN显著高于水稻土。气候和海拔的影响为：MBC、MBN和MBP含量随着≥ 0℃积温、≥ 10℃积温、年均温和年均降水量的增加呈指数减少，而随干燥度和海拔增加呈线性增加。不同成土母质中，MBC、MBN和MBP含量均为灰色冲积物显著高于老冲积物。不同土地利用方式下，三者含量为草地显著高于水田和旱地，水田、旱地和林地差异不显著。皮尔森相关分析和冗余分析表明，MBC和MBN均与≥ 0℃积温、年均温呈极显著负相关（P < 0.01），与海拔呈极显著正相关关系，MBP与母质呈现极显著负相关关系。逐步回归分析表明，MBC主要受年均温、干燥度、年均降水量和母质的影响；MBN主要受海拔、干燥度和年均降水量的综合影响；MBP主要受母质、年均温、≥ 10℃积温和年均降水量的调控。因此，川西平原土壤MBC、MBN、MBP能灵敏地反映不同采样点气候的变化，可为该区气候变化下土壤碳、氮、磷的响应预测提供参考。
Abstract:The characteristics of soil microbial biomass carbon (MBC), soil microbial biomass nitrogen (MBN), and soil microbial biomass phosphorus (MBP) contents, and their responses to climate, altitude, parent material and land use in the western Sichuan plain were investigated by regional survey and statistical analysis. The key influencing factors were subsequently revealed, which provided theoretical guidance for soil quality management in western Sichuan plain. Results showed that MBC, MBN and MBP were significantly higher in alluvial soil than in paddy soil, fluvo-aquic soil, and yellow earth (P < 0.05); moreover, MBC/MBN of fluvo-aquic soil was significantly higher than that of paddy soil. With respect to the influence of climate and elevation, MBC, MBN, and MBP exponentially declined with increasing accumulated temperature above 0℃, accumulated temperature above 10℃, mean annual temperature (MAT) and mean annual precipitation (MAP). However, they were augmented with increasing aridity and altitude. For different parent soil materials, the soil that developed from gray alluvial soil had higher MBC, MBN and MBP contents than those developed from glacial till. Meanwhile, they were significantly higher in the grassland than in paddy field and dry land. However, there were no significant differences between paddy field, dry land, and forest land. Pearson correlation and redundancy analyses revealed that the MBC and MBN had highly significant negative relationships with accumulated temperature above 0℃ and MAT, while, they had highly significant positive relationships with altitude (P < 0.01). In addition, MBP had a highly significant negative relationship with parent material. Furthermore, stepwise regression analysis showed that the main impact factors for MBC were MAT, MAP, and parent material, and aridity; MBN was affected by altitude, aridity, and MAP; MBP was primarily controlled by parent material, accumulated temperature above 10℃, and MAP. Therefore, soil MBC, MBN and MBP can sensitively reflect the climate change in different sampling points in western Sichuan plain, providing an essential basis for predicting the response of soil carbon, nitrogen, and phosphorus to climatic changes.
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