Soil Nutrient And Microorganism As Well As Enzyme Activity In Hippophae Rhamnoides And Platycladus Orientalis Mixed Forest

The biomass, root distribution character, soil physical property, soil nutrient ,the main soil biological properties, such as the populations of soil-inhabiting microorganisms and enzyme activity in soils under the mixed forest of Hippophae rhamnoides and Platycladus orientalis , pure forest of Platycladus orientali,were analyzed and compared.The results showed:(1) The mean height, DBH, individual volume and stand biomass were higher in the mixed stand than those in the pure stand. The distribution of total stand biomass in the mixed stand were more reasonable and evener than that in the pure stand .And aboveground biomass in the mixed stand were higher than that in the pure stand. The biomass of arbor layer distributed in both stands in the order: trunk>branch>leaf. But the percentage of distribution of arbor layer were different in the two stands. The percentage of trunk was lower in the mixed stand than that in the pure stand, while the percentage of branch and leaf were higher in the mixed stand than those in the pure stand respectively;(2) The vertical distribution of Platycladus orientalis root system (diameter≤1 mm and 1~3 mm ) in the pure stand were mainly distributed over soil 0~60cm soil layers, yet those in the mixed stand were distributed deeper and evener in 0~180cm soil layers. And the vertical distribution of the Platycladus orientalis root system(diameter≥3mm) in the mixed stand was the same as that in the pure one. The extents of horizontal distribution of the Platycladus orientalis root system (diameter≤1mm and 1~3mm) in the mixed stands were broader than those in the pure stand, yet the extent of horizontal distribution of the other one (diameter≥3mm) in the mixed stands was narrower than that in the pure stand;(3) Compared with the pure stand, soil bulk density of each layers in the mixed stand were respectively reduced. On the contrary, soil porosity and water capacity were increased to a certain extent;(4) Compared with pure Platycladus orientalis, Platycladus orientalis mixed stand could improved soil organic matter, soil N, P and K contents.And the pH values of each soil layers in the mixed stand were higher than those in the pure stand generally. The every kind of nutrient content showed the trend of decreasing gradually with the increasing soil depth in profilers;(5) Compared with pure Platycladus orientalis, Platycladus orientalis mixed stand increased the amounts of bacteria , actinomyces, fungi and azotobacter. The total amount of microorganisms were higher in Summer than Sping in the growing season;(6) The activity of invertase, urease, catalase, protease, and polyphenol oxidase of the mixed stand were higher than those of the pure stand. The five kinds of enzyme activity showed the significantly seasonal dynamics, and it depended on the sorts of enzyme itself; (7) Correlation analysis indicated that there were significant correlations among soil organic matter and soil bulk density with almost all soil physical and chemical and biological properties. And it demonstrated that the explanations for soil physical and chemical and biological properties and their change tendency based on soil organic matter and soil bulk could be reasonable. Significant correlations were showed between soil chemical properties and the populations of soil-inhabiting microorganisms and enzyme activity. So the populations of soil-inhabiting microorganisms and enzyme activity could be used as appraisal indictors for soil fertility.