Effects of Stand Age and Soil Layer on Soil Nutrients and Readily Oxidizable Organic Carbon Concentrations of Eucalyptus citriodora Plantations
[Objective]To investigate the effects of stand age and soil layer on soil nutrient contents and readily oxidizable organic carbon(ROC),and provide scientific reference for improving soil C sequestra-tion quality of plantation.[Method]This study measured the soil physical and chemical properties and ROC contents of two kinds of Eucalyptus citriodora Hook.plantations with two ages(3a and 20a)and soil layers(0～10,10～20,20～40,40～60,and 60～100 cm)in Suixi,Zhanjiang City,Guangdong Province.[Result]The results showed that the stand age significantly affected the soil physical properties,C,nitro-gen(N),and phosphorus(P)contents and C∶N,C∶P and N∶P,but the soil layer only had significant ef-fects on soil water content(SWC),total organic C(TOC),total N(TN),total P(TP)and ROC.The soil TOC,TN,and TP of 20a plantation were 138.60%,29.77%,and 56.99%higher than those of 3a planta-tion,respectively,indicating that soil TOC,TN,and TP increased with the increase of stand age.In addi-tion,the soil ROC content of 20a plantation was 49.52%higher than that of 3a plantation,while the ROC/TOC ratio was 30.17%lower than that of 3a plantation,indicating that soil C stability of 20a planta-tion increases with the increase of stand age,which is attributed to the higher accumulation of TOC while less accumulation of ROC with the increase of stand age.Correlation analysis showed that the TOC and ROC contents of two plantations with different ages were significantly influenced by TN,TP,C∶N,and C∶P,but the TOC and ROC of 3a plantations also affected by SWC,total porosity,and capillary porosity.[Conclusion]The results of this study show that the stability of soil organic C increases with the increase of stand age,and is easily affected by the supply of soil N and P nutrients.Therefore,in the plantation management practices,the stability of soil C can be effectively improved by properly prolonging the rota-tion periods,as well as the regulation of soil N and P supplement of Eucalyptus plantations.
NETL
NSTL
万方数据
