Study On The Response Of Carbon And Nitrogen Content Of Forest Vegetation To Environmental Factors In Dabie Mountain

Based on multivariate statistical analysis method,in order to jinzhai county in the dabie mountain area of different forest types(coniferous mixed forest,mixed coniferous and broad-leaved mixed forest)needle of forest community as the research object,this paper discusses the dabie mountain area of each elevation range forest soil and litter-tree leaf carbon and nitrogen content and litter and the correlation of soil carbon reserves and environmental factors,the main results were as follows:(1)Soil physical and chemical properties of different forest fractions differ greatly,and soil bulk density increases with altitude;The total porosity and capillary porosity decrease with the increase of soil depth.Non-capillary porosity has no obvious law with soil layer change.The permeability and water content of capillary decrease with the increase of altitude.Respectively,the variation ranges of soil bulk density,capillary porosity and non-capillary porosity in different altitude gradients were:0.58-1.50g/cm~3,36.20%-55.47%and 5.20%-24.87%.(2)Soil carbon reserves were 44.24~119.6t/ha,with an average value of 82.05t/ha,and soil nitrogen reserves were within the range of 0.75~6.89t/ha,with an average value of 3.98t/ha.The soil carbon and nitrogen reserves are in line with the positive correlation with the altitude,which increases with the increase of the altitude.The change trend is obvious,and the change range of carbon and nitrogen ratio is 7.84-51.49.Soil carbon and nitrogen reserves vary greatly among different forest types.There was no significant difference in total nitrogen and alkali-dissociated nitrogen content at different altitude gradients.The difference of soil nitrate nitrogen content was significant.There was a significant correlation between alkaline nitrogen,total organic carbon and total nitrogen content in soil(P<0.01).The pH value was positively correlated with basic nitrogen and total organic carbon.Ammonium nitrogen has a significant negative correlation with pH.(3)The content of carbon,nitrogen and carbon/nitrogen in most leaves of plants showed a trend of decreasing with altitude.The carbon content of the whole community decreased with the increase of altitude,and the change of nitrogen content and carbon/nitrogen ratio was small.The annual mean temperature has certain influence on carbon and nitrogen content and carbon/nitrogen ratio of vegetation community and main plant leaves.(4)The carbon content of litters increases with the increase of altitude,but the carbon content of forest litters is high in some low-lying areas.There is a significant positive correlation between the content of soil organic carbon and the content of litter nitrogen and the content of litter carbon.The dominant tree species had a great influence on the accumulation of litter,while the carbon content of litter was higher in deciduous trees and lowest in coniferous forests.