【作者】 池丽娟；

【导师】 毛艳玲；

【作者基本信息】 福建农林大学 ， 土壤学， 2012， 硕士

【摘要】 本研究以本底条件比较一致的地处亚热带地区的天然林（阿丁枫）、人工林（杉木和木荷以及封育林）、园地（桔园和茶园）、坡耕地为研究对象，通过研究土地利用变化对土壤、团聚体结合态有机碳的影响，以及结合态有机碳与土壤全碳之间的相关关系分析，来揭示亚热带山地红壤固碳的团聚体保护和化学键合机制，通过比较干筛和湿筛法在研究两种结合态有机碳的差异，了解在亚热带地区土壤团聚体的干、湿筛法的适用性，分析土壤团聚体易氧化态有机碳、矿物保护态以及化学抗性有机碳对全碳的贡献以及与土地利用变化的关系，了解有机碳在土壤中的保护过程和矿化过程，这些都涉及土壤有机碳的固定与稳定，阐明土地利用变化对土壤有机碳固定的影响，从而为调整我国亚热带山地土地科学的利用方式、增强碳汇能力提供思路。主要有如下结论：1天然林转化为人工林、园地、坡耕地以后，土壤中的结合态有机碳出现一定程度的下降，其中，钙键结合态有机碳的下降幅度高于铁铝键结合态有机碳，但是下降幅度的差异不显著，且0-10cm土层的结合态有机碳含量大于10-20cm土层。对于团聚体内部的结合态有机碳来说，土地利用变化对它们的影响也比较大，天然林转化为其他利用土地以后，铁铝键结合态有机碳的下降幅度极显著高于钙键结合态有机碳的下降水平，特别是天然林转化为坡耕地后，团聚体内部的结合态有机碳的损失率最高达到97.18%，其差异原因可能在于铁铝键结合态有机碳主要为松结态，钙键结合态有机碳主要为稳结态，因此，土地利用方式的转变，使铁铝键合态有机碳的下降程度更大。而且对于不同粒径的团聚体，结合态有机碳在<0.25mm微团聚体内部的降低幅度最大，也就是说微团聚体中结合态有机碳对全碳的贡献最为突出。2干筛和湿筛两种不同的团聚体筛分方法对不同粒径团聚体两种结合态有机碳的影响不一致。对团聚体钙键结合态有机碳含量造成一定差异，但是差异不显著。铁铝键结合态有机碳，湿筛相对于干筛来讲，造成了其含量的降低。而两种筛分方法对结合态有机碳造成两种迥异的结果可能是与它们具有不一致的热稳定性，以及与腐殖物质不一致的络合力有关。3天然林转化为其他利用土地以后，土壤各粒径团聚体的易氧化态有机碳含量都发生大幅度的损失，特别是开垦为农用耕地后，易氧化态有机碳储量损失高达约87%，这表明易氧化态有机碳对土地利用变化响应比较敏感。同一利用方式土壤不同粒径团聚体中，微团聚体里的易氧化态有机碳的含量大于大团聚体中的相应含量，因此，土地管理过程中，更应该注意减少对微团聚体的干扰，以减少有机碳的损失。4林地转化为园地或是坡耕地，土壤团聚体的各个粒径中矿物保护态有机碳出现很大程度的降低，特别是开垦为坡耕地后，损失量高达97%。同样，化学抗性有机碳含量也出现比较大的损失，但幅度小于矿物保护态有机碳，其最大损失量也达70%左右。同一利用方式不同粒径团聚体中的矿物保护态以及化学抗性有机碳都表现为微团聚体大于大团聚体（杉木林除外）。5不同土地利用方式下，团聚体中结合态有机碳与全碳均有极显著的相关关系。土壤中结合态有机碳与全碳的相关关系则变化不一，其中，天然林、人工林中钙键结合态有机碳与全碳有极显著正相关关系，但是园地无相关关系，对于铁铝键合态有机碳，在各个利用方式土壤中，均和全碳无相关关系，所以，团聚体中结合态有机碳可以作为表征全碳含量的指标之一。各个土地利用方式团聚体的易氧化态有机碳含量与全碳含量均有显著性相关，全碳含量的增加会带动易氧化态有机碳含量的上升。因此，土壤团聚体中易氧化态有机碳可以作为反映土地利用变化的敏感指标之一。不同粒径团聚体中化学抗性有机碳、矿物保护态有机碳与全碳含量均无显著性相关。更多还原

【Abstract】 In this study,select the same conditions of the natural forests (Altingia gracilipes),plantation(Cunninghamia lanceolata and Schima and seal silviculture),orchard (citrus orchard and teagarden),slope farmland which located in the subtropical regions as the research objects,throughresearching the land use changes to influence on soil,aggregates speciation organic carbon,and therelationship between speciation organic carbon and soil carbon to reveal the protection ofmountain soils carbon sequestration aggregates and chemical bonding mechanism insubtropical,through comparing dry sieving with wet sieving to study the differences between twokinds of speciation organic carbon to understand the applicability of dry and wet sieving methodin soil aggregates in the subtropical regions，analysis soil aggregates easily oxidized organiccarbon.Mineral protected organic carbon and chemical recalcitranced organic carbon madecontribution to the total carbon and the relationship between land use changes,provide ideas forthe adjustment of mountain land used in scientific way,and enhance the capacity of carbon sink insub-tropical area in our Country,so as to further illustrate the impact of land use change on soilorganic carbon sequestration,these are all of great significance to promote the ecological cycle forachieving sustainable use of the northern Fujian land. Mainly the following conclusions:1After natural forest conversion to plantation,orchard and slope farmland,the whole soilorganic carbon decreased in some extent, the Ca-SOC decline more than Fe（Al）-SOC,but thedescender was not significant， and the content of soil organic carbon in0-10cm soil horizon wasmore than10-20cm. For the internal aggregates speciation organic carbon,the land use changeshave an effect on them,after natural forest converted to other used land， the decline of theFe（Al）-SOC was significantly higher than the Ca-SOC,especially in natural forest conversion tothe sloping land,the loss rate of the internal aggregates speciation organic carbon is up to97.18%，the difference may be due to the Fe（Al）-SOC is mainly loose state,Ca-SOC is mainly steadystate,therefore,land use change in the pattern,so that a greater degree of Fe（Al）-SOC declinedorganic carbon knot steady state,therefore,the change in land use make a greater descender inFe（Al）-SOC.The different size of Aggregates,speciation organic carbon make the greatestdescender of internal aggregates speciation organic carbon in the <0.25mm, which means thatSOC in soil aggregates made the greatest contribution to the total carbon.2Two different aggregates screening method of dry sieving and wet sieving make differenceinfluence on two different kinds of particle size aggregate speciation organic carbon.It causedsome differences in Aggregates Ca-SOC content， but was not significant.For Fe（Al）-SOC,interms of the wet sieving and dry sieving,the wet sieving resulting in a reduction of its content. Twoscreening methods make the two very different results,may be attribute to their inconsistencthermal stability, and inconsistent with the bond of humic substances.3After natural forest conversion for other use of land, the content of LOC in soil aggregates have undergone a significant loss,especially reclamation for the arable land,the loss of LOCreserves up to about87%,it is suggest that LOC is more sensitive to the changes of land use. In thesame way use of different soil particle size aggregates,the content of LOC in micro-reunion ismore than large aggregates. So that,in the process of land management,should pay attention toreduce the interference of micro-aggregates in order to reduce the loss of organic carbon.4The conversion of forest land to the garden or sloping land,appeared a large extentreduction in the particle size of soil aggregates,mineral protected organic carbon,especiallyreclaimed to sloping land,the rate of loss is up to97%. Similarly,the content of chemicalrecalcitranced organic carbon is relatively large loss,but the magnitude is less than the mineralprotected organic carbon,the maximum loss amount is up to about70%. in the same use patternsof different size aggregates mineral protection of state,and chemical recalcitranced organic carbonare both assume the micro-aggregates are greater than large aggregates (except for Cunninghamialanceolata).5Under different land use pattern,there are very significant correlation between bond-organiccarbon and total carbon of soil aggregates,but varied in soil.In natural forest and plantation,thereare highly significant positive correlation between the Ca-SOC and SOC，and no correlation inorchard.There is no correlation between Fe（Al）-SOC and SOC in each soil of different land usepattern.Therefore,bounded organic carbon in soil aggregates can be used as one of the indicatorsthat characterize the total carbon content.Sililarly,the content of LOC significantly related to thecontent of SOC,the increasing in SOC will lead to the rising of the content of LOC,LOC in soilaggregates can be used as a sensitive indicator reflects the land use change.Mineral protectedorganic carbon and chemical recalcitranced organic carbon were not significantly correlated toSOC in different size of soil aggregates.更多还原