【作者】 郭永清；

【导师】 阮宏华； 郎南军；

【作者基本信息】 南京林业大学 ， 生态学， 2010， 博士

【摘要】 随着全球气候变暖,森林碳循环成为当前研究的热点,而人工林土壤碳循环也是全球碳循环的重要组成部分之一,本研究对全面了解我国人工林土壤有机碳的动态具有重要的意义。本文采用固定样地监测与室内实验相结合的方法,对云南红河流域干热河谷3种不同密度膏桐人工林以及膏桐人工林地、香蕉地和草地3种不同土地利用方式下不同类型土壤活性有机碳含量、土壤碳密度、土壤活性有机碳和矿质氮的时间和空间变化动态、膏桐人工林生物量、生产力、不同器官含碳率、碳分配特征进行了研究,结果表明:(1)3种不同密度膏桐人工林,随着土层厚度的增加,土壤活性有机碳含量逐渐减小。土壤总有机碳(TOC)和易氧化碳(ROC)含量大小顺序均为:株行距1.5m×2m>株行距3m×3m>株行距2m×3m;土壤水溶性有机碳(WSOC)大小顺序为:株行距1.5m×2m>株行距2m×3m>株行距3m×3m;土壤微生物生物量碳(MBC)大小顺序为:株行距3m×3m>株行距1.5m×2m>株行距2m×3m。全氮、总有机碳和土壤温度是影响土壤活性有机碳含量的主要因子,适当密植可以提高土壤有机碳的含量。(2)3种不同土地利用方式下土壤TOC、WSOC、MBC和ROC含量变化较复杂。0～10cm土层TOC、WSOC和ROC含量以膏桐人工林地最大,香蕉地次之,草地最小;10～25cm和25～40cm土层TOC、WSOC和ROC含量以香蕉地最大,膏桐人工林地次之,草地最小;而MBC含量在0～10cm、10～25cm和25～40cm土层均为香蕉地最大,草地次之,膏桐人工林地最小,土壤总有机碳、全磷是影响土壤活性有机碳含量的主要因子。(3)在3种不同密度膏桐人工林地和3种不同土地利用方式下,土壤活性有机碳含量表现都具有明显的季节变化特征,即WSOC和ROC平均含量均为干季>雨季,而MBC平均含量均为雨季>干季。(4)土壤矿质氮(NO3--N和NH4+-N)含量在3种不同密度膏桐人工林地和3种不同土地利用方式下均表现出明显的空间和季节变化特征。随着土层厚度的增加,硝态氮和铵态氮含量逐渐减小;膏桐林地和草地土壤硝态氮雨季初期含量最大,干季平均含量>雨季平均含量;膏桐林地和草地土壤铵态氮含量在干季末期最小,在雨季最大,雨季平均含量>干季平均含量;香蕉地受人为干扰较大,硝态氮和铵态氮含量季节变化不明显。(5)建立了膏桐人工林生物量估算模型Y=25.005(D2H)0.952,根据样方调查资料,估算出膏桐人工林生态系统的生物量为26.025t·hm-2,年平均净初级生产力为10.827t·hm-2·a-1,林分碳密度为5.54t·hm-2。(6)膏桐人工林不同器官含碳率大小顺序为:果实(56.74%)>干枝(45.87%)>根(45.12%)>叶(45.12%),全株平均含碳率为47.27%;土壤表层0～10cm有机碳含量和碳密度分别为16.61g·kg-1和22.76t·hm-2。更多还原

【Abstract】 The dynamics and characteristics of soil labile organic carbon(MBC,WSO,ROC),mineral nitrogen and the biomass of Jatropha curcas were studied in 3 different densities Jatropha curcas plantation and 3 different land use types(Jatropha curcas plantation, banana plantation and grassland)by the fixed plots combined with laboratory mtthods in dry-hot valley of Honghe river region,Yunnan Province,China. The results showed as follows.(1)The sequence of TOC and ROC conten were planting spacing 1.5m×2m>3m×3m>2m×3m; The sequence of WSOC content were planting spacing 1.5m×2m>2m×3m>3m×3m; The sequence of MBC content were planting spacing 3m×3m>1.5m×2m>2m×3m; The soil labile organic carbon content decreased with the increasing of soil depth in the same planting density. The correlationship analysis showed that, soil total nitrogen ,total organic carbon and soil temperature is the main ecological facrors. Three factrors have an effect on soil labile organic carobn content and accumulative contribution rates of these 3 factors accounted for 93.67%.(2)The variation of TOC、WSOC、MBC and ROC content in different soil depth were inconsistent at 3 different land use types. The sequence of TOC、WSOC and ROCcontent at 0～10cm soil depth were Jatropha curcas plantation >banana plantation>grassland. The sequence of TOC、WSOC and ROCcontent at 10～25cm and 25～40cm soil depth were banana plantation > Jatropha curcas plantation >grassland; The sequence of MBC content at 0～10cm,10～25cm and 25～40cm soil depth were banana plantation > grassland > Jatropha curcas plantation; the correlationship analysis showed that, soil organic carbon and total phosphorus were the main ecological factors and there has an effect on soil organic carbon content and the accumulative contribution rates of these 2 factors accounted for81.27%.(3)There was a same variation characteristic of the soil labile organic carbon content at 3 different planting spacing Jatropha curcas plantations and 3 different land use types in dry-hot valley. The mean content of WSOC and ROC in the dry season were higher than that in the rain season; the mean content of MBC in the rain season was higher than that in the dry season;(4)There was a obvious temporal and seasonal variation characteristic of soil mineral nitrogen(NO3--N and NH4+-N)content at 3 different planting spacing Jatropha curcas plantations and 3 ifferent land use types. NO3--N and NH4+-N content decreased with the soil depth increasing. Soil NO3--N content was the highest at the beginning of rain season and mean content in the dry season was higher than that in the rain season at the grassland. The NH4+-N content was the lowest in the end of dry season and the highest in the rain season and mean content in the rain season was higher than that in the dry season at the Jatropha curcas plantations and grassland. (5)The biomass Regression model Y=25.005(D2H)0.952 was set up and applied. The biomass and annual net primary productivity were 26.025t·hm-2 and 10.827t·hm-2·a-1 of Jatropha curcas ,respectively.(6)The sequence of carbon ratio in different organs of Jatropha curcas were fruit(56.74%)>stem(45.87%)>root(45.12%)>leaf(45.12%) and the whole tree carbon ratio was 47.27%. the soil organic carbon content and carbon density were 16.61g·kg-1 and 22.76t·hm-2,respectively.更多还原