上海城市森林土壤理化性质

为了从植物群落角度探究城市森林土壤的理化性质，采集上海市中心城区（外环线以内）公园绿地、居住区绿地、单位附属绿地和道路绿地等4种功能区森林绿地的土壤，分6种群落类型（常绿阔叶林、落叶阔叶林、常绿针叶林、落叶针叶林、常绿灌木林和落叶灌木林），3个土壤分层（0～10，10～20和20～30cm）进行理化性质测定。结果表明，30cm以上的土壤有机质平均质量分数为15．52g·kg^-1，属于低等水平；全氮和全磷质量分数分别为3．78和1．13g·kg^-1，属于中下水平。表层土壤中有机质和全氮质量分数均较高，随着剖面深度增加逐渐减小，磷质量分数未发现有递减性规律变化。土壤密度为1．44～1．60g·cm^-3，表明人类活动使上海城市绿地土壤的紧实度增大。针对上海森林土壤的状况，提高绿地土壤尤其是新建绿地土壤的肥力水平，以增强氮磷等营养元素质量分数；疏松土壤，以利于透气保水；乔、灌植被分层布局．能更好地增加城市森林土壤有机质并收到更好的景观效果。图4表3参25

Soil physical and chemical properties in Shanghai's urban forests

To explore the soil physical and chemical properties in regards to the vegetation community of urban forest, and to inquire the relationship between soil and the vegetation from the urban ecology angle, soil was collected from park green spaces, road green belts, residential areas, and green space affiliated to units within the external circle highway of Shanghai City. Based on the community structure, a system of 6 forest types consists of evergreen broad-leaved forest, deciduous broadleaved forest, evergreen coniferous forest, deciduous needle-leaf forest, evergreen shrub forest and deciduous shrub forest was determined. And the polts were ascertained according to the fan-shaped grid method of landscape pattern. Physicochemical properties were measured at soil depths of 0 - 10, 10 - 20, and 20 - 30 cm. Results showed that average soil organic matter（SOM） above 30 cm was 15.52 g·kg^-1, average total nitrogen（TN） was 3.78 g·kg^-1, and average total phosphorus（TP） was 1.13 g·kg^-1. SOM and TN in the surface layer were rich and gradually decreased with depth, but TP did not show a gradual downward trend. Soil density was between 1.44 - 1.60 g·cm^-3. Because average SOM, TN, and TP in the top 30 cm of urban green belt soil in Shanghai were low and compaction had increased soil density, measures are needed to improve fertility levels, especially in the newly-established green belts, to enhance the nutrient content and increase the landscape effect. [Ch, 4 fig. 3 tab. 25 ref.]