Main Characteristics and Spatial Distribution of Urban Soils in Kaifeng

Urban soils,a special soil type,formed along with the development of city,have unique characteristics. With the method of square grid,137 surface soils samples were set in Kaifeng City. On the basis of field investigation and laboratory analysis,the basic characteristics of urban soils was studied,and the results showed that: soil density,water content,pH,organic matter and total nitrogen of urban soils are different from rural soils and were spatially heterogeneous. Soil density in topsoil followed the order of recreational district traffic district residential district cultural /educational district administrative district industrial district,and the value declined from the northwestern area to southeastern area. The value of pH was above 8,increasing from southeastern area to northwestern area. The content of soil organic matter followed the order of industrial district administrative district traffic district residential district cultural /educational district recreational district,taking on the annular shape in horizontal distribution,which decreasing from eastern area to western area. The order of content of total nitrogen was industrial district administrative district traffic district residential district cultural /educational district recreational district,decreasing from southeastern area to northwestern area.