Study On Ecostoichiometry Characteristics And Carbon Sequestration Of Pinus Tabulaeformis Plantations In Eastern Inner Mongolia

In the context of global climate change,research on carbon sequestration status,rate and potential of plantations has become a hot issue in the field of global climate change ecology research.Therefore,scientific assessment of carbon sequestration characteristics of different climate regions and different types of plantations,and the coupling relationship among C,N and P can be analyzed from the perspective of ecochemometrics,which can reveal the carbon fixation and maintenance mechanism of artificial forest to some extent,and provide scientific basis for the sustainable management of artificial forest.Pinus tabulaeformis plantations has outstanding ecological functions in carbon sequestration,soil conservation,and water conservation.It is one of the main tree species for artificial afforestation in Inner Mongolia.In order to explore the eco-chemometrics and carbon sequestration factors of the Pinus tabulaeformis plantations,the Pinus tabulaeformis plantations in the eastern part of Inner Mongolia was studied,and space was used instead of time and ecological model simulation.The contents of C,N and P were determined in various organs and soils of different forest ages of Pinus tabulaeformis plantations in the study area.Based on the national biomass database,the effects of forest stand characteristics and meteorological factors on carbon sequestration of Pinus tabulaeformis plantations were studied.At the same time,in order to reveal the influence of C-N coupling on carbon sequestration potential of plantations,FORECAST model was used to simulate the long-term effects of nitrogen addition treatment on carbon sequestration in Pinus tabulaeformis plantations.The main findings were as follows:?1?The carbon storage of tree layer and soil layer increased gradually with the increase of forest age,the average carbon content of each organ was 502.49 mg/g,the average carbon storage of tree layer was 39.59 t/hm²,the average carbon storage of soil layer was 60.30 t/hm²,and the total average carbon storage of vegetation and soil was 99.88 t/hm².The carbon storage of the same forest age was higher than that of tree layer.Climate characteristics,forest structure and soil depth are the main factors affecting the carbon reserves of Pinus tabulaeformis plantations in the study area.The differences between marginal and central distribution areas are mainly related to climate gradient change and plantation management measures.?2?With the increase of forest age,the average C content increased gradually,and the average P content and N content showed the characteristics of high P content and low N content in young forest.With the increase of forest age,the P content decreased and the N content increased.The highest value of leaf C:N was 61.38 in young forest and the lowest value was 37.89 in the near mature forest.The highest values of C:P and N:P were 455.03 and12.01,respectively,and both appeared in near-mature forests.The lowest values of C:P and N:P were 385.78 and 6.28,respectively,appeared in young forests.However,all the values of N:P were less than 14.Therefore,it is judged that the growth of Pinus tabulaeformis in this area was mainly limited by N content.?3?The contents of C,N and P in soil decreased with the increase of soil depth.The content of C in soil surface layer is the smallest in young forest,which increases gradually with the increase of forest age and reaches the maximum value in near mature forest,and the content of N and P is the maximum in young forest,which decreases gradually with the increase of forest age and reaches the minimum value in near mature forest.The highest values of soil C:N and C:P were 23.22 and 33.89 respectively in near-mature forest,while the lowest values of soil C:N and C:P were 4.55 and 8.75 in young forest.The highest value of soil N:P was 2.48 in mature forest and the lowest value was 1.15 in near-mature forest.?4?The relationship model between different stand characteristics,climatic factors and carbon storage of Pinus tabulaeformis plantations was established by multiple stepwise regression method.The multivariate regression model constructed are all significant by F test and T test?P<0.01?,and the variance expansion factor VIF is less than 5,indicating that there is no strong linear correlation between the relevant explanatory variables,and the multicollinearity is very weak.Therefore,the carbon storage function relationship of Pinus tabulaeformis plantations constructed by considering forest characteristic factors and meteorological factors comprehensively is more suitable than that constructed by considering each factor alone.?5?FORECAST model was used to study the different nitrogen content on the long-term effects of Pinus tabulaeformis plantations carbon sequestration.Compared with the control treatment?0 N?,with the increase of nitrogen content,the organic carbon storage in vegetation and soil basically remained stable from 90 kg N hm^-2 r^-1 treatment.To some extent,it reflects that the increase of nitrogen deposition can promote carbon sequestration of plantation forest ecosystem in northern region.It is a systematic project to realize the sustainable management of Pinus tabulaeformis plantations.Under the background of global climate change,the adaptive management of plantations has a more promising development in carbon sequestration.The study on the C-N-H2O coupling circulation mechanism of Pinus tabulaeformis is an important research direction in the future.The main technical approaches to solve such problems are to combine ecological model technology and quantitative remote sensing technology with large-scale sample survey data.