不同植被群落下喀斯特土壤养分及生物化学性质特征

Characteristics of Soil Nutrients and Biochemical Properties Under Different Vegetation Communities in Karst Area

为了探讨植被群落对喀斯特土壤养分和生物化学性质的影响,对贵州茂兰国家级自然保护区不同植被群落下土壤养分、基础呼吸、微生物量碳及酶活性进行比较研究。结果表明:不同植被群落之间土壤养分含量差异显著,土壤总有机碳、全氮、全磷、碱解氮和有效磷表现为裸露地<草丛<灌丛≤乔林;土壤基础呼吸表现为裸露地<灌丛<乔林<草丛,诱导微生物量碳为裸露地<灌丛<草丛=乔林,而熏蒸微生物量碳为裸露地<草丛<灌丛<乔林;不同植被群落下土壤蔗糖酶活性高于裸露地,但不同植被群落间差异不显著,土壤脲酶活性有着裸露地<草丛=灌丛<乔林的趋势,而土壤碱性磷酸酶活性表现为裸露地<灌丛<乔林<草丛;土壤呼吸商和诱导微生物量与熏蒸微生物量比值均表现为乔林=灌丛<草丛=裸露地。结果分析表明,不同植被群落下喀斯特土壤养分水平及其凋落物差异影响着土壤微生物群落结构及活性,而土壤微生物执行着土壤营养元素生物化学过程,其群落结构和活性又影响着土壤养分水平及养分有效性。

Soil nutrient pools,microbial activities and enzyme activities were studied to understand the effects of vegetation communities on soil eco-chemical properties in Maolan National Nature Reserve,Guizhou province.The results showed that soil nutrient pools,such as soil organic carbon,total N,total P,hydrolyzable N,available P,increased in the order：Bareland grass communitybush community≤forest community;soil microbial biomass carbon by fumigation-extraction（FE-Cmic） increased with same order as soil nutrient pools,while soil respiration and soil microbial biomass carbon by calculation from substrate-incubation respiration（SIR-Cmic） performed barelandbush communitygrass community≤forest community;soil invertase activities were significantly lower under bareland than those under lands with vegetation,otherwise no significant difference was found between different vegetation communities;soil urease activities were in a increasing order： Barelandgrass community=bush communityforest community,while alkaline phosphatase activities in the order：Barelandbush communityforest communitygrass community;the ratio of SIR-Cmic to FE-Cmic and of basal respiration to FE-Cmic（qCO2） under bareland and grass community was significantly higher than those under bush and forest communities.Soil nutrient status and litters under different vegetation communities drove the changes in microbial community structures and activities,in turn,which affected soil nutrient status and nutrient availabilities by controlling the biochemical transformation process of soil nutrient elements.