Surface Litters Nutrient Returning And Carbon Fix For Five Different Kinds Of Forest Types In Alpine Region,Qinghai

In this study, five different types of forest were selected to study birch litter of the nutrient return and carbon fix and investigate the characteristics of nutrient return and carbon fix according to the climatic characteristics of alpine region and carries on the research analysis to soil respiration and its influencing factors of different types of forest in order to provide evidence for nutrient management and material cycle more accurate in alpine region.The results show that:1)with the deepening of litter decomposition level, litter of five stands in the organic carbon content, availablephosphorus, the ratio of carbon and nitrogen, and carbon phosphorus ratio showed a decreasing trend, the litter nutrient of Betula platyphylla and mixed forest of picea crassifolia and Betula platyphylla were affected by nitrogen while Larixprincipis-rupprechtii, picea crassifolia, mixed forest of picea crassifolia and Larixprincipis-rupprechtii were affected bu nitrogen and phosphorus co-limit of two elements;2)withered leaves is the major component of litter in five stands, the elemental concentration of nitrogen and phosphorusget maximal value on flower and fruit litter, litter fall and returning nutrient amount in growing season have significant influence on watercontentofsoil, besides, as same as nutrient return, although the density distribution of carbon elementof various litter fractions and different stands are respectively different,return amount of carbon element is directly effected by litter fall which is the major dominant factor;3)soil respiration rate isreduced evidently by stripping the litter(p<0.05), there is no significant liner correlation between watercontentofsoil and soil respiration, the contribution of respiration of litter in mixed forest of P.crassifolia and B.platyphylla(44.9%) is higher than mixed forest of P.crassifolia and L.principis-rupprechtii(41.9%), L.principis-rupprechtii(38.5%), P. crassifolia(35.9%) and B.platyphylla(19.3%), the litter of B.platyphylla in growing season is mainly manifested as carbon fix which the rate was 0.915t/hm2,while the rest of four stands manifested as emission, which the rate were L.principis-rupprechtii(0.057t/hm2), P. crassifolia(0.198t/hm2), mixed forest of P.crassifolia and L.principis-rupprechtii(0.458t/hm2), mixed forest of P.crassifolia and B.platyphylla(0.882t/hm2).