Ziwuling Of Natural Pine Forest Soil Microbial Ecology

Natural Chinese pine forests, which is one of the important forest plant species in forest recovery and protection in the Loess Plateau, is also the significant links of forest community natural succession process in this region. Soil, which is the vital important environment factor during plant succession, is the key index of function recovery and maintain of the eco-system. Study on the relationship among soil community structure characteristic and soil fertility as well as enzyme activity could further understand the statue and effect of soil microbe in the process of natural Chinese pine forests during different succession stages, which also play an important role in the process of function recovery and maintain of the eco-system in this region.Therefore, taking the natural Chinese pine forests with different growth years in Ziwuling forest region of the Loess Plateau as research object; organic matter, total nitrogen, available nitrogen, available phosphorus, available potassium, pH,water content Catalase, Urease,Protease. lnvertase, Cellulose and Polyphenol oxidase as well as Alkaline phosphatase of soil samples were determined by traditional methods so as to investigate the change law of soil physical and chemical properties and soil enzyme activity along plant succession; the three main micro-groups and major functional groups of soil microbe was investigated based on the method of plate cultivation and MPN method, besides, the soil microbial biomass carbon (MBC) was also determined through the method of chloroform fumigation; the soil micro-community composition was studied with the method of terminal restriction fragment length polymorphism (T-RFLP), which would be helpful to further understand status and function of function recovery and maintain of the eco-system in this region.Results show that:1) Total nitrogen, organic matter, available nitrogen and available potassium as well as water content of soil samples showed an increasing trend but available phosphorus and pH were reduced as the succession prolonged.2) Catalase showed a decreasing trend but cellulose, urease and invertase increased, and polyphenol oxidase as well as alkaline phosphatase of soil samples showed forword increase and decrease afterword trend along the succession.3) Both total number of soil microbe and soil MBC showed an increasing trend as the succession prolonged. Addinationally, soil actinomycetes play the determining effect on community diversity than soil becteria.4) The three main micro-groups number of soil microbe form the natural Chinese pine forests with the growth year of 70, determined by effective components extracted form the litter fall in this region, showed an increasing trend separately; System cluster result showed that the number treated by birch and liaodong oak is extremely higher than of the chniese pine.5) There is a higher T-RFLP maps similarity between soil samlple of 40a and 70a, and both of them shows a middle similarity with 25a soil sample, and they has a lower similarity with the 10a; the soil genetic diversity show a increasing trend from 10a to 40a but decreas till70a.The results above represent that:1) As the the forest litter fall accumulation increased, the feritility, including soil organic and total N improved, show an increasing trend as the succession prolonged; Organic acid form the organic acid decomposition make the soil pH stay at lower level, which could restrict the availability of P.2) The complex the plants community structure and increased litter fall under the forest plants which are benefit for the accumulation of soil Urease and Invertase, it indicate that the soil fertility here is getting better and better; besides, the improvement of soil Urease would be helpful to the level of N, which consequently improve the Protease level; according to Chinese pine litter fall of itself characteristic, it would be benefit for the accumulation of soil Cellulose, moreover, the litter fall itself could produce more organic acid, which would interrupt the level of soil Alkaline Phosphatase.3) The distribution of three main micro-groups number of soil microbe is getting more averaged and the number of Actinomycetes play more significant role than the Bacterium in the micro-diversity; The increased litter fall under the forest plants would offer the rich C to the microbe growth, thus, the MBC level at the preliminary stage improved slowly but it showed an increasing trend as the succession time prolonged.4) Soil microbe number form the soil of natural Chinese pine forests with the growth year of 70, determined by effective components extracted form the litter fall in this region, showed an increasing trend separately; System cluster result showed that the number form hardwood litter fall is extremely higher than of the conifer and the litter fall from coriaceous was located between them; it tells us that reasonably plants setting would be extremely important to the plantation growth.5) The soil micro-community genetic diversity was studied with the method of terminal restriction fragment length polymorphism (T-RFLP), it represented that there is high diversity similarity during the earlier succession, and it shows a higher similarity as the succession develops but it sharply decreased till 70a, its pricinple is valuable and necessary to be further studied.