Identification Of Environmental Factors Affecting Carbon Storage In Tea Plantations And The Significance Of Carbon Sinks Promoted By Tea Trees In Municipal Green Space

The gain and loss of soil carbon in terrestrial ecosystems is very important for changes in atmospheric carbon dioxide(CO₂)concentration and environmental problems caused by it.In the face of the sharp increase in atmospheric CO₂concentration and its global warming and extreme climate events,in-depth research the influencing factors and mechanisms of soil carbon in various terrestrial ecosystems have become urgent problems for scholars.At present,there is a relatively comprehensive study of soil organic carbon(SOC)reserves and fluxes in forest ecosystems and farmland ecosystems.For plantations,such as forest and farmland,the research and understanding of the flux are few,especially the influencing factors of its SOC storage and its mechanism are rarely explored.Although altitude,temperature,rainfall,and land use types are important factors affecting SOC storage,it is difficult to change the above factors in these specific areas in land use management.These factors mainly affect SOC storage by affecting soil environmental factors.Therefore,identifying the soil environmental factors that affect SOC storage and clarifying the impact weight of each factor are significant for promoting carbon storage in the ecosystem.Tea tree is not only a widely planted economic forest,but because of its beauty,it is also used for urban road greening.In this study,we determined more than 30 soil environmental factors,such as SOC,soil basic physical and chemical properties,chemical elements,mineral types,microorganisms,etc.by stratified measurement of 0-140 cm soil layer.The structural equation model(SEM)was used to quantitatively analyze the impact of SOC primary and secondary soil environmental factors stored.Try to find out the soil environmental factors that affect the SOC storage of tea gardens in southwestern China and the weight of each factor that affects the SOC,with a view to changing these factors in the cultivation management of tea gardens to promote SOC storage,and provide low-carbon cultivation and soil management for tea gardens.The results show that the soil environmental factors affecting the SOC storage of tea gardens in this area are:water content,N,active iron(Fe_o),S,P,Ca,redox potential(Eh),clay,Br,and Mn.They accounted for 18.85%,18.74%,16.28%,13.07%,8.62%,6.16%,5.57%,4.47%,4.25%and 4%of all soil environmental factors.Unlike large-scale studies,soil temperature and p H changes in the study area are small without affecting SOC storage.The use of organic fertilizers increased C,N,S,and P,and N,S,and P helped the storage of SOC.Where conditions permit,SOC storage can be improved through proper irrigation;it is worth noting that Fe_o plays a very important role in SOC storage.According to previous studies and analysis of the data in this study,we found a set of Fe-NSP coupling mechanisms that promote SOC storage with moisture participation.We found that in soils rich in Fe content,soil moisture,N,S,and P can activate crystalline iron to increase Fe_o,and the increase in Fe_oincreases the stability of SOC.Therefore,the application of magnetic fertilizer(iron oxide)or the application of N,S,and P can promote the formation of Fe_oin the soil,and has a non-negligible effect on the promotion of SOC storage.Therefore,regardless of whether it is an economic forest tea plantation or an urban green tea plantation,the improvement of the above-mentioned soil factors is conducive to improving its SOC storage capacity.Because urban green tea gardens have regular fertilization and irrigation,it is very beneficial to increase the carbon sink of the tea garden soil in these places.Therefore,it is recommended to expand the use of tea trees in future municipal greening.