林龄和土层对柠檬桉林土壤养分和易氧化有机碳的影响  

Effects of Stand Age and Soil Layer on Soil Nutrients and Readily Oxidizable Organic Carbon Concentrations of Eucalyptus citriodora Plantations

作　　者：何普林 徐其贤 王忠林 张振源 刘悦 顾晓娟 周庆 莫其锋 HE Pu-lin;XU Qi-xian;WANG Zhong-lin;ZHANG Zhen-yuan;LIU Yue;GU Xiao-juan;ZHOU Qing;MO Qi-feng(China Forestry Group Leizhou Forestry Bereau Co.,Ltd,Zhanjiang 524043,Guangdong,China;College of Forestry and Landscape Architecture,South China Agricultural University,Guangzhou 510642,Guangdong,China)

机构地区：[1]中林集团雷州林业局有限公司,广东湛江524043 [2]华南农业大学林学与风景园林学院,广东广州510642

出　　处：《林业科学研究》2024年第2期115-123,共9页Forest Research

基　　金：广东省林业科技创新项目“粤西地区优质高产林分碳封存潜力提升的施肥技术体系构建”(2022KJCX017);“碳中和背景下广东省典型优势树种大径材培育关键技术体系构建与示范”(2022KJCX015)。

摘　　要：[目的]人工林土壤的地力维持和有机碳稳定性受到林龄和土层的极大影响。本文旨在探明林龄和土层对柠檬桉人工林土壤养分含量和易氧化有机碳(Readily oxidizable organic carbon,ROC)的影响,为人工林土壤固碳质量的提升提供科学参考。[方法]本文测定了广东省湛江市遂溪县2种林龄柠檬桉人工林的土壤理化性质和易氧化有机碳含量及其垂直分布特征,探讨林龄(3年生和20年生)和土层(0~10、10~20、20~40、40~60和60~100 cm)对柠檬桉人工林土壤碳稳定性的影响及其调控因素。[结果]林龄显著影响柠檬桉人工林土壤的物理性质、碳氮磷含量及C∶N、C∶P和N∶P,但土层仅对自然含水量(SWC)、总有机碳(TOC)、全氮(TN)、全磷(TP)和ROC存在显著影响。20年生柠檬桉人工林土壤TOC、TN和TP比3年生分别高138.60%、29.77%和56.99%,说明土壤有机碳和氮磷养分随着林龄的增加而增加。这是由于随着人工林林龄的增加,地表凋落物和根系提高了土壤有机质的输入进而改善了土壤肥力。20年生柠檬桉林土壤ROC含量比3年生高49.52%,而土壤ROC/TOC值比3年生低30.17%,说明随着林龄的增加,土壤TOC积累的量更多而ROC积累的量相对较少,因而土壤碳稳定性增强。相关分析表明,两种林龄柠檬桉人工林土壤TOC和ROC受到土壤TN、TP、C∶N和C∶P的显著影响,而3年生柠檬桉人工林土壤TOC和ROC还受到土壤毛管持水量、总孔隙度和通气孔隙度的影响,说明柠檬桉幼龄林土壤碳储量及稳定性同时受到土壤物理性质和氮磷养分供应的调控,而成熟林则更容易受到土壤养分供应水平的调控。[结论]柠檬桉人工林土壤有机碳稳定性随着林龄的增加而提高,且容易受到土壤氮磷养分供应的影响。因此,在人工林经营实践中,适当延长轮伐期,并注意调控土壤氮磷养分供应,可以有效提高柠檬桉人工林土壤有机碳的稳定性。[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 sequestration 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,nitrogen(N),and phosphorus(P)contents and C∶N,C∶P and N∶P,but the soil layer only had significant effects 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 plantation,respectively,indicating that soil TOC,TN,and TP increased with the increase of stand age.In addition,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 plantation 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 rotation periods,as well as the regulation of soil N and P supplement of Eucalyptus plantations.

关 键 词：碳稳定性 土壤养分 易氧化有机碳 柠檬桉人工林 粤西地区 

分 类 号：S714.5[农业科学—林学]