Studies On Soil Organic Carbon Content Content Of Alnus Formosana Forest-grass Compound Ecosystem

Forest-grass compound ecosystem, refers to the multi-level artificial vegetations which forms by the forest and the lawn union. In the forestry which is called to mix the junction, or to interplant the Forest-grass. Forest-grass compound ecosystem is a farming and forestry compound ecosystem part, which is a compound name of land utilizable system and the project applied technology, and it has the destination to use the perennial xylophyte and the agriculture, the animal husbandry in the identical land Management unit and adopts the space and time distribution or the short-term interaction modes of business operation, referring to the multi-level artificial vegetations which is formed by the forest and the lawn union. Forest-grass compound ecosystem is also one kind of artificial ecosystem, in system's discussion, which should follow the order of nature, define beneficial Forest-grass multiplexed system, and impel the implementation of Returning farmland to forest project better. In view of this, in order to have the efficiency, stability and endurance in the Forest-grass mode of the Returning farmland to forest project, we must study the natural and technical rule of the management and operation, to guarantee the pattern's status and function in improving the ecological environment, to maintain the soil fertility, to increase the farmers' income and regulate the diversification of the economic structure, to provide the theory basis of instructing the production practice of Returning farmland to forest, drawing up the management measure for the Forest-grass compound mode. This article selected three beneficial taking back from agriculture modes as the object of study in Sichuan Danleng County Forest-grass compound ecosystem 's Alnus formosana+Lolium multiflorum Lam, Alnus formosana+ Hemarthria compressa, the Alnus formosana pure crop natural grass pattern, used the method of soil drilling to systematically study these three modes in different seasons, the organic carbon content of different soil layer, C/N and the microorganism quantity, the water-solubility, and the carbon content of readily oxidation, and discussed the influence of the implantation of Lolium multiflorum Lam, Hemarthria compressa to the organic carbon content of the forest land soil and the component. The result indicated:(1)the average soil organic carbon content of these three kinds of modal soil is situated between 13.80～5.98 g·kg-1, and displays the rule:Alnus formosana+ Lolium multiflorum Lam>the Alnus formosana+Hemarthria compressa>the pure crop, Forest-grass compound pattern, between the Alnus formosana pure crop pattern soil profile average organic carbon content the difference not remarkable (P>0.05), the basic trend of the organic carbon content of three kinds of modal soil in different seasons is:Summer>spring>winter>autumn. the average C/N difference is remarkable among three kinds of modal soil's profile (P<0.05).(2)the average content of the microorganism quantity carbon of each soil layers of three kinds of model shows that Alnus formosana+Lolium multiflorum Lam pattern >Alnus formosana pure crop pattern>Alnus formosana+Hemarthria compressa pattern. the difference of the average microbial biomass carbon content between the profile's of the Forest-grass model and the Alnus formosana pure crop pattern is not remarkable (P>0.05), the seasonal variation of SMBC is the fall>the spring>the season>the summer, and there is an obvious synchronized changing tendency between the microbial biomass carbon and the microbial biomass nitrogen.(3) the order for the average water-solubility organic carbon content of three kinds of modal soil is Alnus formosana+Hemarthria compressa> Alnus formosana+ Lolium multiflorum Lam>Alnus formosana pure crop. the difference of the average water-solubility organic carbon content of the soil profile between the Forest-grass pattern and the Alnus formosana pure crop pattern is remarkable (P<0.05), under various patterns,the seasonal variation of the soil water-solubility organic carbon is:Winter>fall>spring>summer.(4) the difference of the average easily oxidizing organic carbon content between the soil profile of the Forest-grass pattern and the Alnus formosana pure crop pattern is not remarkable (P>0.05), the change of the readily oxidation carbon of three kinds of modal soil is small, the biggest difference of different value is 2.18 g·kg-1, the biggest difference of the average profile value is 0.04 g·kg-1; In the 0-10cm soil level, the readily oxidation carbon of the Forest-grass compound pattern is bigger than the Alnus formosana pure crop.there is not an obvious regularity beween the other level Forest-grass compound pattern and the Alnus formosana pure crop,the seasonal variation of the easily oxidation carbon is the fall >the winter>the spring>the summer.(5) After the Pearson correlation analysis among the soil organic carbon content quantity and various activated carbons as well as each kind of activated carbon, finally the result indicated that there is a strong relevance among the edaphon quantity.At the same time, the soil organic carbon content also has the very strong relevance with three kind of soil activeness organic carbon between.The generalized analysis indicated that the Alnus formosana+Lolium multiflorum Lam/Hemarthria compressa Forest-grass compound pattern and the Alnus formosana pure crop compares, because Alnus formosana+Lolium multiflorum Lam/Hemarthria compressa Forest-grass superposable die in the formula the Lolium multiflorum Lam/Hemarthria compressa implanted improved the soil micro environment to a certain extent, increased the soil organic carbon content accumulation, raised the soil organic carbon content active constituent content, according to the above evidence the Forest-grass compound pattern to increased the organic carbon content and the soil fertility aspect has the very big potential.