【作者】 王宪帅；

【导师】 黄从德；

【作者基本信息】 四川农业大学 ， 森林培育， 2010， 硕士

【摘要】 生态交错带(Ecotone)是全球气候变化的最敏感区域,对生态交错带不同土地利用类型土壤有机碳的研究,可为生态交错带土地利用和有效管理提供基础数据。岷江上游山地森林—干旱河谷交错带作为典型的生态过渡区,在抑制干旱河谷上延和延伸亚高山森林生态系统的功能等方面具有十分重要的作用。本文按典型选样的方法,研究了岷江上游山地森林-干旱河谷交错带6种不同土地利用类型的土壤有机碳、微生物生物量碳、水溶性有机碳、易氧化态碳、土壤水分物理性质及它们之间的关系。研究结果表明：(1)6种土地利用类型土壤有机碳含量介于8.86±3.99 gC·kg-1-17.52±7.77gC·kg-1之间,有机碳储量介于56.56±7.21 tC·hm-2-104.15±4.84 tC·hm-2之间,并均随土壤深度的增加而降低；有机碳含量及碳储量的大小顺序都表现为：天然川滇高山栎次生林>灌木林地>灌丛地>经济林>人工刺槐林>农耕地；其中天然川滇高山栎次生林土壤有机碳含量及有机碳储量显著高于其他5种土地利用类型(p<0.05)。这表明,在岷江上游山地森林—干旱河谷交错带不同土地利用类型中,森林土壤是最大的碳储存者。但由于人为干扰以及交错带生态系统的脆弱性及其叠加效应,导致岷江上游山地森林—干旱河谷交错带6种土地利用类型的土壤有机碳低于同区域(岷江上游米亚罗林区)土壤的平均有机碳。(2)6种土地利用类型土壤微生物生物量碳含量介于145.34±64.70mgc·kg-1-411.55±102.12mgc·kg-1之间,其大小顺序依次为：天然川滇高山栎次生林>灌木林地>灌丛地>人工刺槐林>经济林>农耕地；天然川滇高山栎次生林的土壤微生物生物量碳含量高于灌木林地,显著高于其它4种土地利用类型(p<0.05)；6种土地利用类型的土壤微生物生物量碳含量在0-40cm土层下降明显,随着土层的加深,土壤微生物生物量碳含量的降低幅度逐渐减小；6种土地利用类型的土壤微生物生物量碳占有机碳的比率都比较低,介于1.36%-2.35%之间,表明交错带内土壤有机碳有不断下降的趋势。(3)6种土地利用类型的土壤水溶性有机碳含量介于84.41±16.09 mgc·kg-1-198.27±17.75mgc·kg-1之间,其大小顺序依次为：天然川滇高山栎次生林>人工刺槐林>灌木林地>灌丛地>经济林>农耕地,且均随土层的加深而降低；天然川滇高山栎次生林的水溶性有机碳含量显著高于其它5种土地利用类型(p<0.05)；6种土地利用类型的土壤水溶性有机碳占有机碳的比率介于0.82％-1.34%之间,以人工刺槐林最高,灌木林地最低；受交错带内土壤水分特异分布规律影响,6种土地利用类型土壤水溶性有机碳占有机碳的比率在20-40cm土层较高。(4)6种土地利用类型的土壤易氧化态碳含量介于0.90±0.26gc·kg-1-1.84±0.25 gc·kg-1之间,其大小顺序依次为：天然川滇高山栎次生林>灌木林地>灌丛地>人工刺槐林>经济林>农耕地；天然川滇高山栎次生林的易氧化态含量高于灌木林地,显著高于其它4种土地利用类型(p<0.05)；各土地利用类型的土壤易氧化态碳含量均随土层的加深而降低；6种土地利用类型的土壤易氧化态碳占有机碳的比率都比较高,介于7.77%-10.50%之间,表明交错带内土壤碳的活性大,容易转化。(5)6种土地利用类型的土壤有机碳、微生物生物量碳、水溶性有机碳和易氧化态碳与土壤容重均呈极显著负相关关系(p<0.01)；受交错带自然条件和人为干扰的双重影响,6种土地利用类型的有机碳和活性有机碳与土壤含水量的相关性不同；6种土地利用类型的土壤有机碳和活性有机碳与土壤PH多呈负相关关系,且相关性不显著,但交错带内土壤PH值过高,在一定程度上不利于土壤有机碳和活性有机碳的积累。(6)农耕地转变为经济林和人工刺槐林后,土壤有机碳含量分别提高了36.73%和21.93%,有机碳储量分别提高了50.56%和25.13%,易氧化态碳含量增加了4.58%和7.53%,微生物生物量碳含量增加了13.16%和23.31%,水溶性有机碳增加的幅度较大,分别为27.28%和71.06%。这表明退耕地还林后土壤有机碳和活性有机碳都增加,但增加的程度与植被恢复的类型有关；同时土壤水溶性有机碳对土地利用变化更为敏感。更多还原

【Abstract】 Ecotone is a sensitive region for global climate change, and study on soil organic carbon under different land use types at ecotone could provide basal data for land management.The mountain forest-drought valley ecotone in the upper reaches of Minjiang River is a typical tension zone,It can inhibit the extension of the drought valley and extension the function of subalpine forest ecosystem.This paper usethe method of sampling by the typical, research on soil organic carbon、microbial biomass carbon、water-soluble organic carbon、readily oxidation carbon、soil water physical property and the relationship between them at mountain forest-drought valley ecotone in the upper reaches of Minjiang River. the results show that:(1) Soil organic carbon content under Six kinds of land use lies between 8.86±3.99 gC·kg-1-17.52±7.77gC·kg-1,Soil organic carbon storage lies between 56.56±7.21 tC·hm-2-104.15±4.84 tC·hm-2,soil organic carbon content and storage were decreased with the soil depth increment.Soil organic content and storage followed the order of Quercus semicarpifolia secondary forest>shrubbery > shrub> economic forest> Robinia pseudoacacia plantation> farmland.Among them, the Soil organic carbon storage under Quercus semicarpifolia secondary forest higher than the other five kinds of land use(p<0.05); show that the forest Soil is the largest carbon storage under different land use types at mountain forest-drought valley ecotone in the upper reaches of Minjiang River. However, because of the Jamming and frangibility of ecotone, soil organic carbon of mountain forest-drought valley ecotone in the upper reaches of Minjiang River under six kinds of land use was lower than the same area(Miyaluo forest area in the upper reaches of Minjiang River).(2) Soil microbial biomass carbon content under six kinds of land use lies between 145.34±64.70mgc·kg-1-411.55±102.12 mgc·kg-1,they followed the order of Quercus semicarpifolia secondary forest> shrubbery> shrub> Robinia pseudoacacia plantation >economic forest> farmland .Soil microbial biomass carbon content of Quercus semicarpifolia secondary forest higher than the shrubbery, it were much higher than the other four types of land use(p<0.05).The extent of reduction were significantly in the 0-40cm soil layer under Six kinds of land use,it were decreases gradually with the soil depth increment.The percentage was lower which of Soil microbial biomass carbon to soil organic carbon under Six kinds of land use lies between 1.36%-2.35%, show that the Soil organic carbon have downward trend at ecotone.(3) water-soluble organic carbon content of soil profile under six kinds of land use lies between 84.41±16.09mgc·kg-1-198.27±17.75mgc·kg-1,they followed the order of Quercus semicarpifolia secondary forest>Robinia pseudoacacia plantation>shrubbery>shrub>economic forest> farmland,water-soluble organic carbon were decreased with the soil depth increment.water-soluble organic carbon content of Quercus semicarpifolia secondary forest were much higher than the other five types of land use(p<0.05);The percentage of soil water-soluble organic carbon to Soil organic carbon under Six kinds of land use lies between 0.82%-1.34%,the robinia pseudoacacia plantation presents a maximum conductivity and a minimum shrubbery.Effect of specific distribution of soil moisture at the ecotone,the percentage were higher in the 20-40cm soil layer which of water-soluble organic carbon to soil organic carbon under six kinds of land use.(4)Readily oxidation carbon content under six kinds of land use lies between0.90±0.26gc·kg-1-1.84±0.25 gc·kg-1,they followed the order of Quercus semicarpifolia secondary forest>shrubbery>shrub>Robinia pseudoacacia plantation>economic forest> farmland; Readily oxidation carbon content of Quercus semicarpifolia secondary forest higher than the shrubbery, it were much higher than the other four types of land use(p<0.05); soil readily oxidation carbon content were decreased with the soil depth increment under all kinds of land use types.The percentage was higher which of Soil readily oxidation carbon to soil organic carbon under Six kinds of land use lies between 7.77%-10.50%, show that the Soil organic carbon have high reactivity and easy conversion at ecotone.(5)soil organic carbon,microbial biomass carbon,water-soluble organic carbon and readily oxidation carbon under six kinds of land use showed a significant negative correlation with Soil bulk density (p<0.01);Soil organic carbon and soil active organic carbon of six kinds of land use have different correlation with soil water content under the double influence which natural conditions of ecotone and human disturbance.Soil organic carbon and soil active organic carbon of Six kinds of land use have negative correlation with soil PH and they had a great closely correlation.The ecotone of the soil PH is too high but go against accumulation in soil organic carbon and soil active organic carbon at a certain extent.(6)Arter farmland transformed into robinia pseudoacacia plantation and economic forest ,Soil organic carbon content increased by36.73% and 21.93%, Soil organic carbon storage increased by 50.56% and 25.13%, readily oxidation carbon content increased by 4.58% and 7.53%, microbial biomass carbon content increased by 13.16% and 23.31%, there was a big rate of increase amplitude of the water-soluble organic carbon,increased by 27.28% and 71.06%.It shows that the soil organic carbon and soil active organic carbon is increased after conversion of cropland to forest, but the degree of this increase is related to vegetation types.The water-soluble organic carbon is more sensitive to land use change at mountain forest-drought valley ecotone.更多还原