Characteristics And Evaluation Of Soil Organic Carbon In Guansi River Basin Of Mianyang

Sichuan basin hilly region is the most important agricultural land is the upper Yangtze river,water conservation and one of the key regions of biodiversity protection,in the national economic and social development strategy has the important status and role.To explore the regional vegetation restoration on SOC and carbon library management,the influence of the enhanced stability of soil ecosystem,improve the function of soil and water conservation,soil carbon emission reduction,etc all have important significance.In mianyang lawsuit river basin based on this,this research within five kinds of main vegetation types and different slope located in 0 to 40 cm depth of SOC particles,easy oxidation of organic carbon,organic carbon,soil nitrogen content were determined,the organic carbon density and SOC,soil C/N and carbon management index indicators for this paper.Results are as follows:1)5 kinds of different plant types in the basin is 0?20 cm,20-40 cm depth SOC content are significant(P<0.05).SOC content present a tendency of decreasing with the increase of soil depth,0 to 20 cm SOC content were greater than 20-40 cm soil.In 0 to 40 cm the whole soil profile,organic carbon content order:EF>CF>T>FL>CMF.Due to surface runoff erosion of SOC,CMF SOCcontent is lower than the other 4 kinds of plant.Different slope positions and SOC content were significant(P<0.05).CF and EF the single species forest 0 to 40 cm SOC content in the whole change trend is shown as:down>middle>up,and SOC content was significantly correlated(P<0.01),r of 0.731 and 0.859.T,CMF in different slope positions 0?20 cm no obvious correlation between SOCcontent.20-40 cm SOC content and 0?20 cm under the organic carbon content in the same position of the distribution agreement.In addition to the economic forest in slope located in 0?20 cm and 20-40 cmSOC content of different depth gap is not big,the variation coefficient was 3%,other forest types under different slope positions 0-20 cm and significant difference was found in 20-40 cm SOC content,the discrete degree is higher.2)The ROC content between different plant types reached extremely significant level(P<0.01).ROC content decrease with soil deepen and overall performance,different plant types between 0 to 40 cm ROC content is high and low order do not agree with SOC performance,the average ROCcontent order:EF>T>CF>CMF>FL,significant(P<0.05).The SOC and ROC content show a certain linear relationship.Significant between different slope position and ROC content.In addition to the CMF,CF,EF slope positions related to the ROC content was not significant(p>0.05).20-40 cm ROC content with 0-20 cm ROC content under the same slope of distribution,roughly the same slope a ROC content is focused on the 0?20 cm depth,and decrease with the soil deepen.3)0 to 40 cm depth POC content in the basin is average performance:FL>EF>T>CMF>CF,significant(P<0.05).0-20 cm and POC content differences between 20-40 cm significantly(P<0.05),all show the decrease with the increase of soil depth.FL 0?20 cm average POC content(8.15 g/kg)4 plant types are significantly higher than the other.POC content differences between different slope positions significantly(P<0.05),EF 0 to 20 cm,20-40 cm POC content under different slope positions significantly(P<0.01),r of-0.620,0.527.Hill plant POC content of discrete degree is higher,higher than the slope and hill;Different plant types of organic carbon of soil particles distribution ratio in each of the significant difference between soil layer;There were significant correlation between different plant types and POC or SOC(P<0.05).4)0?20 cm of SOCdensity of not less than 20-40 cm soil layer.Average 0?20 cm soil layer SOC density:T>CF>EF>FL>CMF,20-40 cm SOC density distribution features are:EF>FL>CF>T>CMF.Guansi basin area 0 to 40 cm SOC storage of 8.88×104 t,organic carbon in the 0 to 40 cm soil profile on the order:FL>CF>CMF>T>EF,the distribution pattern is closely related to the class around the area.5)5 kinds of different plant types in the basin is the RR/c value range of 7.8%to 7.8%,the artificial planting of EF and T RR/c value is bigger,human disturbance to SOC activity and stability of variation;Agricultural soils because of frequent ploughing,soil permeability good,active organic matter easy to break down the RR/C value is the lowest;ICM is significant between different forest types(P<0.05),with the increase of soil depth of ICM,6)Different plant types TN content of significant(P<0.05).0?20 cm depth TN content in the basin is average performance is:EF>T>FL>CF>CMF,20-40 cm TN content average order is same;TN content extremely significant(P<0.01),all show the decrease with the increase of soil depth;Two layer TN content latterly discrete degree is higher;Different slope TN content significant(P<0.05);0-20 cm of the slope surface and the 20-40 cm soil slope in TN content to reduce the rate of the fastest,uphill and downhill TN change rate is low;C/N in the position and the downhill in different forest types between different soil layer change range is not big,hill and slope positions in different forest types of soil C/N shows the tendency of decrease with the increase of soil depth.