为研究城市功能分区对绿地土壤活性碳氮的影响,选择合肥市不同功能区(老商业区、老工业区、居民服务区、近郊森林公园)绿地土壤为研究对象,分析了土壤微生物量碳氮(MBC、MBN)、溶解性碳氮(DOC、DON)、有机碳(SOC)、全氮(TN)以及土壤基本理化性质的差异及其相互关系。结果表明,功能区类型对土壤微生物量碳氮及溶解性碳氮影响显著(P〈0.05),且0~30 cm土层含量均为近郊森林公园高于城区内各功能区。土层厚度对MBC、DOC、DON含量影响显著,MBC、DON在各功能区中均随土层深度增加而递减,森林公园MBN、DOC均为10~20 cm含量最高。不同功能区MBC/MBN在6~14间波动,以此预测本研究范围内土壤微生物可能以真菌和放线菌为主,细菌较少。本研究未证实DOC与MBC、MBC与DON、DON与MBN间的相关性,MBC+DOC、MBN+DON比MBC、DOC、DON、MBN更能反应土壤活性碳氮库与土壤微生物量。总体来说,相比城区内各功能区,近郊森林公园更利于土壤生物量碳氮及溶解性有机碳氮的积累。
In order to evaluate the influence of urban function partitioning on the contents of soil available carbon and nitrogen, soil microbial biomass carbon (MBC) and nitrogen (MBN), dissolved organic carbon (DOC) and nitrogen (DON), soil organic carbon (SOC), total nitrogen (TN) and soil basic physicochemical characteristics were determined in four urban functional areas (primary shopping center, primary industrial estate, the science, culture and education center, suburban forest park). The results showed that the types of functional areas had significant effects on MBC, MBN, DOC and DON (P 〈 0.05), and their contents in 0 - 30 cm soil layer were higher in suburban forest park than those in the other three functional areas within the city. Soil layer had significant influence on the contents of MBC, DOC and DON (P 〈 0.05). The contents of MBC and DON decreased with increasing soil depth. In addition, the values of MBN and DOC at 10 - 20 cm soil layer were the highest in forest park. The ratio of MBC to MBN (MBC / MBN) in the four types of functional areas ranged from 6 to 14, indicating that fungi and actinomycetes may be the main constituents of soil microbial biomass compared with bacteria. There were no correlation between DOC and MBC, MBC and DON, DON and MBN in the study areas. The sum of MBC and DOC (MBC + DOC) was better to reflect soil available carbon than MBC and DOC alone; similarly, the sum of MBN and DON (MBN + DON) was better to reflect soil available nitrogen than DON and MBN alone. Overall, compared to the functional areas within the city, suburban forest park was more conducive to the accumulation of soil microbial biomass carbon and nitrogen and dissolved organic carbon and nitrogen.