| This thesis studied six main coastal protective forest models in Shanghai through measuring the soil enzyme activity and fertility characteristics. The results were described as follows:(1)The regularity of seasonal variation of Soil invertase activity in different forest land was different. The seasonal variety of soil urease was December> March> June> September. The seasonal variety of soil alkaline phosphatase was March> December> September> June. The seasonal variety of soil catalase was June> March> September> December. The seasonal variety of soil protease was March> June> December> September. The soil invertase had different seasonal variation regularity in different forests.(2)The activity of soil urease, alkaline phosphatase,protease and invertase decreased with the increased depth of the soil layer, and the soil surface had the largest ration. However, the distribution of soil catalase was not obvious in the soil layer and the difference among them is tiny.(3)The enzyme activity as well as soil physical and chemical properties of the forest land were better than beach land, which means the coastal protection forest could improve the soil fertility.(4)All of the five soil enzymes had close relationship, and all of them were deeply affected by the soil physical and chemistry characters.(5)The main factor that effect soil urease activity was the total porosity. The main factor that both effect soil alkaline phosphatase activity and protease activity was the pH value. The main factors that effect soil catalase activity were the soil salt content and total phosphorus content. The main factors that effect soil invertase activity were the pH value and available potassium content. |
