黄土丘陵区深层土壤有机碳对土地利用变化的响应

发布时间：2018-03-07 03:03

本文选题：深层土壤　切入点：有机碳储量　出处：《中国科学院研究生院（教育部水土保持与生态环境研究中心）》2015年硕士论文　论文类型：学位论文

【摘要】：土地利用变化在全球碳平衡及气候变化中起着重要作用。目前对黄土高原地区土壤有机碳库虽然已经进行了大量卓有成效的研究工作,但绝大部分仍是以浅层有机碳含量或者有机碳库大小作为研究对象,而近期一些研究表明,1m以下的深层土壤积聚的有机碳十分可观。该区天然次生林转变为人工林及农田等植被破坏过程中,土壤有机碳变化的研究还鲜见报道,还不足以科学认识该区土地利用变化对土壤有机碳的影响方式和程度。本文以黄土丘陵区子午岭为研究区,以天然乔木林、天然灌木林、人工乔木林、撂荒地、农地5种不同土地利用类型为研究对象,以浅层(0~100cm)土壤为对照,研究深层土壤有机碳储量和有机碳组分对土地利用变化响应的程度、方式、机理,以及土地利用变化后年限与土壤有机碳的关系。并且对土壤溶解性有机碳迁移特征及其动态变化进行了研究,进一步了解深层有机碳来源问题。研究取得以下主要结果:1.黄土丘陵子午岭林区天然乔木林、天然灌木林、人工乔木林、撂荒地、农地0~200cm有机碳储量分别为134.65t?hm-2、96.23t?hm-2、124.98t?hm-2、76.03t?hm-2、82.75t?hm-2,深层(100~200cm)土壤有机碳储量分别占0~200cm总有机碳储量的33%、29%、31%、34%、42%。2.不同土地利用类型间0~200cm土壤有机碳含量有一定差异,以天然乔木林和人工林地最高,其次是天然灌木林地,撂荒地和农田土壤有机碳含量最低。不同利用类型间浅层土壤有机碳含量差异显著,但深层土壤有机碳含量差异不大。3.土地利用变化对土壤有机碳储量影响显著,浅层比深层变化更敏感。天然乔木林转变为人工乔木林、天然乔木林转变为农田、天然灌木林转变为撂荒地及农田四种土地利用转变方式导致浅层土壤有机碳储量减少幅度为2%~48%,深层减少幅度为12%~22%。4.天然灌木林地转变为农田土壤有机碳储量随着开垦时间的增长而降低,开垦0~30年,有机碳含量储量下降较快,降幅为31%。浅层(0~100cm)土壤有机碳储量在开垦30~50年有略微下降,降幅为8%,50年后基本不变。而深层(100~200cm)土壤有机碳储量变化幅度较小,介于4%~15%之间。5.不同土地利用类型土壤深层(60~200cm)活性有机碳占0~200cm活性有机碳含量的8%~51%。不同土地利用转变方式不仅对浅层(0~60cm)土壤活性有机碳有影响,对深层(60~200cm)也有一定影响。天然乔木林转变为人工乔木林、天然乔木林转变为农田、天然灌木林转变为撂荒地及农田四种土地利用转变方式深层土壤易氧化性碳减少幅度为1%~21%;土壤微生物量碳减少幅度为8%~25%。6.土壤溶解性有机碳含量随土壤剖面深度的增加而逐渐降低,与有机碳含量显著相关;浅层(0~100cm)和深层(100~200cm)溶解性有机碳含量分别占0~200cm土层总含量58%和42%。灌木林地DOC淋溶10d后土壤0~200cm整个土层DOC增加量增幅为23%;入渗30d的浅层(0~100cm)和深层(100~200cm)DOC分别仅增加5%和4%。
[Abstract]:Land use change plays an important role in global carbon balance and climate change. But most of them still study the content of shallow organic carbon or the size of organic carbon pool. Some recent studies have shown that the accumulation of organic carbon in the deep soil below 1 m is considerable. In the process of the natural secondary forest being transformed into artificial forest and farmland, there are few reports on the change of soil organic carbon. This paper takes Ziwuling of loess hilly area as the research area, takes natural tree forest, natural shrub forest, artificial arbor forest, abandoned land, etc. Five different land use types of farmland were studied, and the degree, mode and mechanism of deep soil organic carbon storage and organic carbon components response to land use change were studied. The relationship between soil organic carbon (SOC) and land use change (LUCF), and the characteristics and dynamic changes of soil dissolved organic carbon (SOC) transport were also studied. The main results of the study are as follows: 1. Natural Arbor Forest, Natural shrub Forest, artificial Arbor Forest, abandoned Land, and Agricultural Land (0 ~ 200cm) in the Loess Hilly Ziwuling Forest region are respectively 134.65 t ~ (-1)? Hm-2n 96.23t? Hm-2n 124.98t? Hm-2? 76.03t? Hm-2n 82.75t? The soil organic carbon reserves of 0 ~ 200cm were 3329 ~ 31C ~ (34) ~ (42cm) respectively. There were some differences in soil organic carbon contents between different land use types, among which the natural tree forest and artificial forest land were the highest, followed by natural shrub forest land, the soil organic carbon reserves of 0 ~ (200 ~ 2) cm were higher than that of the natural forest land, and the soil organic carbon storage was 100 ~ (100 ~ (200) cm) of the total organic carbon storage of 0 ~ (200 cm), respectively. The soil organic carbon content of abandoned land and farmland was the lowest. The content of organic carbon in shallow soil was significantly different among different utilization types, but there was no significant difference in organic carbon content in deep soil. 3. Land use change had a significant effect on soil organic carbon storage. The shallow layer is more sensitive than the deep layer change. The natural tree forest turns into the artificial tree forest, the natural tree forest turns into the farmland, The conversion of natural shrub forest to abandoned land and farmland has resulted in the decrease of soil organic carbon reserves in shallow layer by 248%, and in deep layer by 120.22.4. the natural shrub land is transformed into farmland soil organic carbon storage with the opening of soil organic carbon storage. With the increase of reclamation time, During the period of 0 ~ 30 years of reclamation, the content of organic carbon decreased rapidly, the decrease was 31%.) the soil organic carbon reserve decreased slightly from 30 to 50 years, the decrease was 8%, and after 50 years it was basically unchanged.) the change of soil organic carbon storage in the deep layer (100 ~ 100 cm) was relatively small. The content of active organic carbon in 0 ~ 200 cm soil is 80.51% of the total active organic carbon content of 0 ~ 200cm. Different land use transformation patterns not only affect the soil active organic carbon content in shallow layer (0 ~ (60) cm), but also have a significant effect on the soil organic carbon content of 0 ~ 200 cm in different land use types. Natural Arbor Forest is transformed into artificial Arbor Forest and Natural Arbor Forest turns into farmland. Conversion of natural shrub forest to abandoned land and farmland four types of land use transformation methods the extent of reduction of oxidizing carbon in deep soil is 1 / 21, and that of microbial biomass carbon in soil is 8 / 25.6.The content of dissolved organic carbon in soil varies with the depth of soil profile. Increasing and gradually decreasing, There was a significant correlation between organic carbon content and organic carbon content. The content of dissolved organic carbon (DOC) in the soil layer of 0 ~ 200cm was 58% and 42cm, respectively. After 10 days of DOC leaching in shrub land, the increase of DOC in the whole soil layer of 0 ~ 200cm was 23%, while that in the shallow layer of 30d infiltration was 5% and 47.The content of DOC in deep layer (100200cm) increased only 5% and 4cm, respectively.
【学位授予单位】：中国科学院研究生院（教育部水土保持与生态环境研究中心）
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S153.6;F301.2

【引证文献】