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选择福州市南江滨公园内建植年龄(10 a)相当的阔叶树黄花槐(Sophora xanthantha C.Y.Ma)林、针叶树南洋杉(Araucaria cunninghamii)林以及较为常见的沟叶结缕草(Zoysia matrella)草坪为研究对象,以建园之前遗留林木番石榴(Psidium guajava Linn.)林为对照,采用吸管分散分离法提取土壤微团聚体,分析了城市公园不同植被土壤微团聚体组成、平均质量直径(MWD)、平均质量比表面积(MWSSA)等.结果显示:保留林土壤以粗微团聚体(0.25~2 mm)为主,而后建3种植被土壤以<0.02 mm粒级的微团聚体为主体,保留林MWSSA和分形维数显著低于后建林地,MWD显著高于后建林地,大粒级颗粒含量越多,分形维数(D)越小.可见,公园绿化过程中若保留原有林木,可以保护土壤微团聚体稳定性.后建3种植被土壤的分形维数,阔叶林低于草坪和针叶林,但差异尚未达到显著水平,这可能与建植年龄还较短有关.不同植被类型土壤微团聚体的分形维数越低,土壤有机质和碱解氮含量越高,说明分形维数可以作为城市绿地土壤定量化描述土壤肥力水平的指标.
Choosing the Sophora xanthantha CYMa forest, the Araucaria cunninghamii forest and the more common Zoysia matrella lawn in Nanjiangbin Park of Fuzhou City, Taking the Psidium guajava Linn. Forest before the establishment of the park as a control, soil microaggregates were extracted by pipette dispersive separation. The composition of soil microaggregates, the average mass diameter (MWD) ), Average specific surface area (MWSSA), etc. The results showed that mainly coarse aggregates (0.25-2 mm) were the main soil in the reserved forests, and then the three kinds of vegetation soils were mainly composed of microaggregates with grain size <0.02 mm, The MWSSA and the fractal dimension of the reserved forest were significantly lower than those of the post-built forest, and the MWD was significantly higher than that of the post-built forest. The larger the content of the large-sized particles and the smaller the fractal dimension (D) Can protect the stability of soil micro-aggregates.The fractal dimension of the soil after the establishment of three kinds of vegetation is lower than that of the lawn and the coniferous forest, but the difference has not reached the significant level, which may be related to the shorter age of planting. Vegetation type soil The lower the fractal dimension of the aggregates, the higher the soil organic matter and nitrogen content, the fractal dimension can be described as a quantitative description urban green areas soil fertility indicator.