Study On Soil Physical And Chemical Properties And Carbon Storage Of Different Red Cone Plantations In South Subtropical Region

Global climate issues are increasingly prominent,affecting human life.As the main body of terrestrial ecosystems,forests have an important regulatory role for the climate.This paper takes four kinds of 15-year-old red cone plantations(Castanopsis hystrix plantation n Castanopsis hystrix + Pinus elliottii mixed forest?Castanopsis hystrix + Michelia macclurei mixed forest?Castanopsis hystrix + Mytilaria laosensis mixed forest)A in the state-owned peak forest farm in Guangxi as the research object.By means of potassium dichromate oxidation-heating method and conventional physical and chemical analysis,etc.The carbon storage allocation,soil physical and chemical properties and microbial biomass differences of different red cone plantations were studied.Designed to provide a scientific basis for improving forest ecosystem services and sustainable management.The main findings are as follows:(1)there were significant differences in SOC,TN,pb,?g and MBC and MBN among different Castanopsis hystrix plantations.With the increase of soil depth,SOC,TN,TP,?g of the 4 forest types decreased gradually,while pb increased gradually.When lowered,pb appears to increase gradually.The SOC,TN,TP,?g,pH and pb of the four forest types in 0-60 cm soil layer were significantly different.And the soil SOC,TN,TP,?g,MBC and MBN were the largest in the mixed forest of C.hystrix +M.laosensis mixed forest.The pH value and pb are the smallest,and the SOC,TN,TP,MBC and MBN of the C.hystrix plantation soil are the smallest,and the pH value and pb are the largest.Correlation analysis showed that MBC was significantly positively correlated with SOC and TP,and negatively correlated with pb.MBN was significantly positively correlated with SOC,TN and TP,and negatively correlated with pb;SOC,TN,TP and pb showed a significant negative correlation.The above results showed that the C.hystrix mixed forest could effectively improve soil nutrient and soil texture.Especially the C.hystrix broadleaf mixed forest could improve soil nutrient and soil texture more than the C.hystrix plantation and C.hystrix coniferous mixed forest.(2)Among the different red cone plantations,the red cone mixed forest can increase the carbon storage of the forest and increase the carbon sink compared with the pure red cone forest.Castanopsis hystrix + Pinus elliottii mixed forest(274.111 t/hm2).?Castanopsis hystrix + Michelia macclurei mixed forest(260.566 t/hm2)?Castanopsis hystrix + Mytilaria laosensis mixed forest(272.774 t/hm2)carbon are much higher than Castanopsis hystrix plantation(213.908 t/hm2).This is due to the reasonable spatial distribution pattern of the three mixed forests,which can make full use of the nutrient space and make full use of the light.Therefore,it can improve the biomass of forest ecosystems and improve soil nutrients and structure,promote carbon accumulation,and increase carbon storage.(3)Among the different red cone plantations,the carbon storage in the arbor layer and soil layer accounted for 99.11%-99.72%of the total carbon storage of the ecosystem.The shrub layer,the herb layer and the litter layer account for only 0.28%-0.89%of the total carbon storage of the ecosystem.The carbon storage of the arbor layer is mainly distributed in the trunk,and the carbon storage of the trunk accounts for 56.77%-62.74%of the carbon storage of the arbor layer.Dry skin,branches,leaves and roots accounted for 37.26%-42.33%of the carbon storage of the tree layer.The carbon storage of the arbor layer of the Castanopsis hystrix + Pinus elliottii mixed forest is the most among the four forest types,and the plant diversity of the shrub layer and the herb layer is also the highest.It indicated that the mixed of Pinus elliottii and Castanopsis hystrix can effectively improve the biodiversity of the red cone plantation ecosystem,the accumulation of carbon storage in the vegetation layer and the yield of wood.The carbon storage in the soil layer(0-100 cm)is mainly distributed in the 0-40 cm soil layer,accounting for 58.55%-62.32%of the total carbon storage in the soil layer.The 40-100 cm soil carbon storage accounts for 37.68%-41.45%of the total carbon storage.The carbon storage in the soil layer of the Castanopsis hystrix + Michelia macclurei mixed forest is the most among the four forest types,followed by the Castanopsis hystrix + Mytilaria laosensis mixed forest.It indicates that the combination of Michelia macclurei,Mytilaria laosensis and Castanopsis hystrix can significantly increase the soil carbon storage of red cone plantation.