Estimation Of Soil Organic Carbon Storage In Bamboo Forests And Its Influencing Factors

As an important part of forest resources in China,bamboo forest has important significance in forest carbon sink function and carbon cycle with its unique biological characteristics.This paper takes ChangNing county of SiChuan province as an example,to investigate the forest soil on the county scale,use the ArcGIS to analyze the spatial and vertical distribution of bamboo forest soil organic carbon,and estimated the soil carbon storage in bamboo forests,that we can enrich China's forest soil carbon storage database,and provide basic data for the simulation,prediction of bamboo forest carbon cycle and its environmental impact.At the same time,the correlation analysis between the soil organic carbon density of bamboo forest and elevation,AN,TN,AK,TK,AP,TP,different types of bamboo forest,different slope directions,different elevation gradients and bamboo forest soil organic carbon were analyzed to explore the influence of different factors on the storage of bamboo forest soil organic carbon.The results show that:(1)The organic carbon storage in the 0-20 cm soil layer of bamboo forest in ChangNing county was estimated by type method to be about 1.05 Tg,and the organic carbon storage in the 0-60 cm soil layer of bamboo forest was 2.43 Tg.The soil organic carbon reserves of bamboo forest in the 0-20cm and 0-60cm soil layers in ChangCing county were estimated by geostatistics as 1.08 Tg and 2.39 Tg.The method of geostatistics to estimate the soil organic carbon storage of bamboo forest is suitable for the study of county scale,and can better reflect the spatial distribution characteristics and spatial progressive law of soil organic carbon density.The general characteristics of the horizontal distribution of soil organic carbon density in the bamboo forest are consistent with the changes of altitude gradient and the characteristics of dense distribution of bamboo forest,which all increase from northwest to southeast,indicating that the soil carbon content is closely related to the altitude and forest density.Meanwhile,the density and content of organic carbon in the 0-20cm soil layer accounted for 43.54%and 44.80%of that in the 0-60cm soil layer,indicating that soil organic carbon was mainly distributed in the surface of the soil,with obvious surface accumulation.(2)The spatial spatial interpolation data of geostatistics showed that the soil organic carbon density of bamboo forest in each soil layer was significantly positively correlated with the altitude,which increased with the elevation,while the measured data of sample points were only significantly correlated with the surface layer.It indicates that the change of elevation gradient has a greater impact on surface soil and the organic carbon cycle in deep soil is longer.The difference of soil organic carbon density of bamboo forest was not significant at all elevations,while the difference of soil organic carbon density of bamboo forest based on spatial interpolation data was significant at all elevations.The analysis results are inconsistent,which may be due to the fact that there are few samples in the higher altitude area due to the limitation of the conditions,and the measured data of sample points vary greatly in each altitude area.The soil organic carbon content of 8 types of bamboo forests was significantly different only in the 20-40cm soil layer between bamboo and four seasons bamboo,while the soil organic carbon content of all bamboo species in other soil layers was not significantly different.It is speculated that the bamboo penis of MAO bamboo forest is deeper because of its larger morphology,thus contributing more to soil carbon in the 20-40 cm soil layer.On the whole,it can be concluded that the soil organic carbon content of bamboo forest is not significantly different among bamboo species,but the contribution of bamboo species with large biomass to soil carbon sequestration may be larger.Moreover,bamboo species with larger shape and deeper distribution have more help to carbon fixation in deep soil.There was no significant difference in soil organic carbon content between the slopes of bamboo forests in different geographical orientations,and the slopes of Yin and Yang were not consistent in different topographies.Therefore,the slope orientation study in geographical orientations was not suitable for the study of soil carbon reserves.(3)The content of soil elements was significantly correlated with the content of soil organic carbon,while the available potassium was negatively correlated with the content of soil organic carbon.In addition,the effect of soil nitrogen on soil organic carbon was higher than that of soil phosphorus and soil potassium.There was a close correlation between total phosphorus and total potassium content in soil,but the correlation weakened with the increase of soil depth.Because organic carbon density is also affected by bulk density and other factors,the influence of nutrient elements on soil organic carbon is greater than that of organic carbon density.Soil organic carbon in each soil layer is more affected by nutrient elements in each soil layer than in other soil layers.Moreover,the influence of soil nitrogen on soil organic carbon in the 20-40cm soil layer is greater than that in the surface and deep soil layer.It is speculated that the reason is that the respiration of bamboo penis is mainly carried out in the 20-40cm soil layer,and the absorption of soil nitrogen promotes the growth and respiration of bamboo forest,thus increasing the soil carbon content.Difference in nitrogen,phosphorus,and potassium in mainly ion form soluble salts or adsorbed on the surface plasma,and promote bamboo after potassium absorbed by ZhuBian photosynthesis to speed up the accumulation of soil carbon,so lead to the negative correlation between,and bamboo forest of rapidly-available potassium absorbed mainly in the soil,and for potash requires further experiments to explore the bamboo forest of potassium absorption threshold.