Study On Carbon Sequestration Capacity And Soil Carbon Storage Of Typical Plant Communities In Huixian Wetland

Guilin Huixian Wetland is the largest karst original ecological wetland in the Lijiang River Basin.As the"kidney"of the Lijiang River Basin,its ecological status is important and special.However,in recent years,long-term human activities in wetlands have increased their damage,and the wetland environment is not optimistic,resulting in a sharp decrease in the area of wetlands,making it impossible to realize some of the original ecosystem functions.Therefore,the related research on carbon sequestration function in wetland ecosystem is particularly important.In this study,typical plant communities in Huixian wetland and soil under different land types were selected as the research objects.Through sample collection and experimental data analysis,the carbon sequestration capacity and influencing factors of typical wetland plant communities are analyzed.Sampling method is used to determine the soil organic carbon content of different soil layers,layered sampling method and potassium dichromate external heating method,and combined with Quick Bird remote sensing image interpretation and field investigation,the area of each land type in Huixian Wetland was obtained,and the wetland was obtained.Soil carbon storage.The evaluation of the soil carbon sequestration value of Huixian wetland combined with the ecosystem value evaluation method provides a reference for strengthening the ecological restoration work and environmental governance of the wetland.The main research results are as follows:（1）The biomass of typical plant communities in Huixian Wetland has obvious differences in the growth season（summer）,and the biomass variation between communities is relatively small.The maximum above-ground biomass of the plant community is Huakrasha community（1902.40g/m²）,and the minimum is lotus community（959.10g/m²）.The maximum underground biomass is the Huakrasha community（1796.15g/m²）,and the minimum is the lotus community（683.56g/m²）.The change trend of community biomass with seasons is similar.In summer,the above-ground biomass is at its maximum.In autumn,the above-ground part gradually withers and the biomass decreases.In winter,the above-ground biomass reaches the lowest.For the underground part,the underground biomass of the lotus community reaches its maximum in summer,and the biomass of the rest of the plant community reaches its maximum in winter.（2）When the single-best plant community is mixed with two or three species or the community type is two and three mixed,the plant community type has a significant impact on plant biomass.Plant community biomass is negatively correlated with p H and water depth H,organic matter and nitrate nitrogen NO3-N are significantly positively correlated（P<0.05）,total nitrogen TN,ammonia nitrogen NH4-N are extremely significantly positively correlated（P<0.01）The effect of total phosphorus TP is not significant.According to the analysis based on the stepwise regression equation,ammonia nitrogen and nitrate nitrogen are the most important environmental factors for the biomass of plant communities.The carbon sequestration capacity of wetland plant communities is the largest in the Chinese Krasha community and the lowest in the lotus community.Compared with the carbon sequestration capacity of typical plant communities in other wetlands in China,the carbon sequestration capacity of most plant communities in Huixian wetland is higher than the domestic average level,and higher than the carbon sequestration capacity of typical plant communities in most typical domestic wetlands.The typical plant communities in the fairy wetland have strong carbon sequestration ability.（3）Based on the random forest algorithm,the accuracy of the typical plant community in the sample is judged.The prediction accuracy is 84.62%for long bud cattail,92.31%for wild rice,92.59%for Hua Krasa,and 93.75%for lotus.The accuracy of reed discrimination is96.30%.Huakrasha is closely related to total phosphorus,ammonia nitrogen and nitrate nitrogen in soil;reed is closely related to p H,total nitrogen and organic matter in soil;lotus is closely related to total phosphorus,ammonia nitrogen and organic matter in soil;wild rice is closely related to soil The total nitrogen,nitrate nitrogen,and p H are closely related;the cattail long bud is closely related to the total phosphorus,nitrate nitrogen and p H in the soil.Wakratha distribution is positively correlated with total phosphorus and negatively correlated with other soil factors;reed distribution is positively correlated with p H,nitrate nitrogen,total phosphorus,ammonia nitrogen,and total nitrogen;lotus distribution is positively correlated with nitrate nitrogen and organic matter The relationship is negatively correlated with total phosphorus and p H;the distribution of wild rice is positively correlated with p H,and is negatively correlated with organic matter and total nitrogen;the distribution of cattail longibracteata is negatively correlated with p H and nitrate nitrogen,and is positively correlated with organic matter.（4）The variation range of soil organic carbon content in Huixian Wetland is8.73g·kg^-1-35.15g·kg^-1,and the order of the average soil organic carbon content in descending order is:forest land,lake wetland,swamp wetland,Farmland,artificial fish ponds.The content of soil organic carbon is not significantly different between 0-10cm and 10-20cm,and there are significant differences between 20-30cm,30-40cm,and 40-50cm（P<0.005）.The content of soil organic carbon is vertical The direction distribution is quite different,and the trend of change decreases with the increase of soil depth,and fluctuates at 10-20cm.The organic carbon density of Huixian wetland varies from 11.90kg/m²-51.70kg/m².The order of organic carbon density is forest land,swamp wetland,lake wetland,farmland and artificial fish pond.Soil organic carbon density of 0-30cm soil layer Accounted for relatively high.（5）The core area of Huixian Wetland is 533.10hm²,with the largest utilization area of farmland,reaching 216.33hm²,accounting for 36.70%.Artificial fish ponds,woodlands,lake wetlands and marsh wetlands account for 17.51%,17.28%,11.97%and 6.97%respectively.The total amount of soil carbon sequestered in Huixian Wetland is 78463.37t C,in order of total carbon sequestration,they are farmland（29226.09t C）,woodland（21905.51t C）,lake wetland（10466.71t C）,artificial fish pond（10388.08t C）,marsh wetland（6476.98t C）.Based on the market value method,carbon tax method,afforestation cost method,combined afforestation cost method and carbon tax method average method,the soil carbon sequestration value of Huixian Wetland was 6,627,700 yuan,81,204,900 yuan,85,981,600yuan,and 83,592,900 yuan,respectively,per unit area The carbon sequestration value is12,400,152,300,161,300,and 156,800 respectively.