The Succesion Of Soil Properties In Urban Economic Radius Area

Base on the soil in urban economic radius of Harbin, the soil fertility was found not onlyincreased in general, but aIso decreased in some case. Because the use of the soil is usuallyvery intensified, a huge sum of input of urban fertilizers such as composted urban waste,garbage and sewage etc would increase the soil fertility, which made an enrichment of certainmaterials such as organic matter, N, P etc in urban areas. But in the view of excessiveuti1ization and improper fertilization, it has also caused some decline in soil nutrientcondition.Soil enzyme activity could be used as the important evaluation index of soil fertiIity. Soilenzyme play a very important role in the transformation of organic matter, N, P into availablenutrient forms that can be used by plants. The results showed that the correlations of organicmatter, N, P with urease/ protease were positively significant, the correlations betweennutrient content and hydrogen peroxidase/ peroxydase was insignificant, but the nutrientcontent and poIyphenol oxidase was found inversely correlated.