侵蚀性花岗岩坡地不同地貌部位土壤剖面风化特征研究
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摘要
为揭示发育于侵蚀性风化花岗岩坡地上不同地貌部位土壤剖面的风化发育特征,在浙江省选择了典型的风化花岗岩坡地:浙江省嵊州市水土保持监测站为研究区,在监测站同一坡面不同侵蚀强度的坡顶、坡中、坡底选取3个典型的土壤剖面(140 cm),从下至上等距离(20 cm)采集土壤样品,共采集21个土样。进行了各层土壤基本理化特性和化学全量的分析,并分别计算了3个剖面不同层次的主要化学风化系数及总的风化强度,结果表明:(1)在强烈侵蚀的花岗岩风化残积坡地发育的土壤,总体发育成熟过程较弱,其进一步的发育与典型的地带性土壤的发育有很大的差异,侵蚀过程严重地影响了土壤的进一步成熟,侵蚀强度越大,则土壤发育越差。(2)土壤剖面总的风化强度不大,上下层的递变差异很小,脱硅富铝化过程随着剖面深度的增加风化程度越来越弱。(3)土壤剖面的化学分层不明显,各种风化指标均在60 cm左右形成了一个分界层,其上受水力侵蚀影响明显,其下呈现出的特性以继承残积母质为主。(4)不同地貌部位的风化发育程度排序为:坡底<坡中<坡顶,其与采样坡面的侵蚀强度排序正好相反。(5)风化程度与有机质和黏粒含量具有较为明显的正比关系,在侵蚀环境下,土壤的物理特性对风化的影响明显,在沉积环境下土壤有机质的影响大于黏粒含量的影响。总之,由于受侵蚀的影响,坡地土壤剖面的淀积层不发育,剖面呈现出的假淀积层不是由淋溶作用形成的,而是具有一定风化程度的风化残积层,结果导致发育于山地丘陵侵蚀性坡地的土壤层次划分不同于常规的土壤层次划分。
【Objective】Strong soil erosion affects profoundly soil development on slopes. On slopes the same in parent material,but different in erosion intensity,soil varies sharply in weathering development degree. In the granite hill and mountain areas of Southeast China,the soil developed on weathering residual slopes suffers severe water erosion,and differs distinctly from other zonal soils in soil weathering development profile. 【Method】 This study in oriented to characterize weathering development of soil profiles at different landform positions of an eroded weathering granite slope. A typical weathering granite slope was selected in Shengzhou,Zhejiang province for monitoring of soil erosion with the help of the Shengzhou Soil and Water Conservation Monitoring Station. On the slope where the station sits,three typical soil profiles(140 cm in depth)were selected at sites different in erosion intensity along the slope from top to bottom,and soil samples were collected 20 cm apart from bottom to top in each soil profile. So a total of 21 soil samples were gathered for analysis of basic physicochemical properties and chemical total contents in various soil layers. On such a basis,calculation was done of main chemical weathering coefficients of the soil layers and total weathering intensity of the soil profiles,separately. As the zonal soil of the studied is red soil,of which the main chemical weathering processes are enrichment of iron and aluminum and leaching of dissolved salts. Therefore,the chemical weathering indices selected in this study were dominantly those that may reflect enrichment of iron and aluminum and leaching of dissolved salts,they are 1Al_2O_3/Si O_2,2 Fe_2O_3/Si O_2,3 R_2O_3/Si O_2,4Al_2O_3/(RO+R_2O)and 5R_2O_3/(RO+R_2O). In order to analyze weathering intensity of each soil layer relative to the bottom layer in the same soil profile and facilitate comparison between the soil layers in weathering intensity,further calculation was performed of relative weathering intensity(I relative)of each soil layer relative to the bottom one. 【Result】The following conclusions were drawn from the analysis and calculation:(1)The soil of the profile at the site of severely eroded weathering residual granite slope is on the whole rather slow in soil developing and maturing process,and differs sharply from the typical zonal soil in further development,and severe erosion greatly hinders maturing processes of the soil;and the severer the erosion,the poorer the soil developed;(2)The soil profile as a whole is not very high in weathering intensity;the variation in weathering intensity between soil layers in the soil profile is very gentle;the peak of weathering intensity appears in the 40~60cm soil layer,instead of the surface soil layer;the processes of desilication and aluminum enrichment weaken with profile depth and intensifying weathering degree;and the decreasing trends of Al2O3/Si O2,Fe2O3/Si O2 and R2O3/Si O2 are quite obvious in all the three soil profiles,which demonstrate that soil weathering degree lowers with profile depth;(3)Chemical stratification of the soil profiles is not distinct,with all the weathering indices forming a boundary layer at about 60 cm in depth;the layers above it are obviously affected by water erosion and those below mainly inherit the properties of the residual soil parent material;(4)In terms of weathering intensity,the three soil profiles display an order of bottom profile < mid profile < top profile,which is just the reverse of that in terms of erosion intensity;(5)Weathering degree is significantly and positively related to the contents of organic matter and clay,and also to physical properties of the soil under erosion;However,the influence of organic matter content is greater than that of clay content in the soil in deposition environment. 【Conclusion】Affected by erosion,the illuvial horizon of soil profile does not develop on slopes,the false illuvial horizon is a certain weathering degree weathering residual layer,but is not formed by eluviations,which leads to the division of soil layer developed from hill and mountain areas differs from conventional method.
【Objective】Strong soil erosion affects profoundly soil development on slopes. On slopes the same in parent material,but different in erosion intensity,soil varies sharply in weathering development degree. In the granite hill and mountain areas of Southeast China,the soil developed on weathering residual slopes suffers severe water erosion,and differs distinctly from other zonal soils in soil weathering development profile. 【Method】 This study in oriented to characterize weathering development of soil profiles at different landform positions of an eroded weathering granite slope. A typical weathering granite slope was selected in Shengzhou,Zhejiang province for monitoring of soil erosion with the help of the Shengzhou Soil and Water Conservation Monitoring Station. On the slope where the station sits,three typical soil profiles(140 cm in depth)were selected at sites different in erosion intensity along the slope from top to bottom,and soil samples were collected 20 cm apart from bottom to top in each soil profile. So a total of 21 soil samples were gathered for analysis of basic physicochemical properties and chemical total contents in various soil layers. On such a basis,calculation was done of main chemical weathering coefficients of the soil layers and total weathering intensity of the soil profiles,separately. As the zonal soil of the studied is red soil,of which the main chemical weathering processes are enrichment of iron and aluminum and leaching of dissolved salts. Therefore,the chemical weathering indices selected in this study were dominantly those that may reflect enrichment of iron and aluminum and leaching of dissolved salts,they are 1Al_2O_3/Si O_2,2 Fe_2O_3/Si O_2,3 R_2O_3/Si O_2,4Al_2O_3/(RO+R_2O)and 5R_2O_3/(RO+R_2O). In order to analyze weathering intensity of each soil layer relative to the bottom layer in the same soil profile and facilitate comparison between the soil layers in weathering intensity,further calculation was performed of relative weathering intensity(I relative)of each soil layer relative to the bottom one. 【Result】The following conclusions were drawn from the analysis and calculation:(1)The soil of the profile at the site of severely eroded weathering residual granite slope is on the whole rather slow in soil developing and maturing process,and differs sharply from the typical zonal soil in further development,and severe erosion greatly hinders maturing processes of the soil;and the severer the erosion,the poorer the soil developed;(2)The soil profile as a whole is not very high in weathering intensity;the variation in weathering intensity between soil layers in the soil profile is very gentle;the peak of weathering intensity appears in the 40~60cm soil layer,instead of the surface soil layer;the processes of desilication and aluminum enrichment weaken with profile depth and intensifying weathering degree;and the decreasing trends of Al2O3/Si O2,Fe2O3/Si O2 and R2O3/Si O2 are quite obvious in all the three soil profiles,which demonstrate that soil weathering degree lowers with profile depth;(3)Chemical stratification of the soil profiles is not distinct,with all the weathering indices forming a boundary layer at about 60 cm in depth;the layers above it are obviously affected by water erosion and those below mainly inherit the properties of the residual soil parent material;(4)In terms of weathering intensity,the three soil profiles display an order of bottom profile < mid profile < top profile,which is just the reverse of that in terms of erosion intensity;(5)Weathering degree is significantly and positively related to the contents of organic matter and clay,and also to physical properties of the soil under erosion;However,the influence of organic matter content is greater than that of clay content in the soil in deposition environment. 【Conclusion】Affected by erosion,the illuvial horizon of soil profile does not develop on slopes,the false illuvial horizon is a certain weathering degree weathering residual layer,but is not formed by eluviations,which leads to the division of soil layer developed from hill and mountain areas differs from conventional method.
引文
[1]吴能森.花岗岩残积土的分类研究.岩土力学,2006,27(12):2299—2304Wu N S.The research of granite residual soil classification(InChinese).Rock and Soil Mechanics,2006,27(12):2299—2304
[2]宋全杰,李海波,李俊如,等.强风化花岗岩动力学参数的试验研究.岩土力学,2013,34(4):1031—1036Song Q J,Li H B,Li J R,et al.The experimental study of strong weathering granite kinetics parameters(In Chinese).Rock and Soil Mechanics,2013,34(4):1031—1036
[3]尚彦军,王思敬,岳中琦,等.全风化花岗岩孔径分布-颗粒组成-矿物成分变化特征及指标相关性分析.岩土力学,2004,25(10):1545—1550Shang Y J,Wang S J,Yue Z Q,et al.The correlation analysis of change features and indicators of pore distribution,particle composition and mineral component indicators of completely weathered granite(In Chinese).Rock and Soil Mechanics,2004,25(10):1545—1550
[4]张抒,唐辉明.非饱和花岗岩残积土崩解机制试验研究.岩土力学,2013,34(6):1668—1674Zhang S,Tang H M.The experimental research of disintegration mechanism of unsaturated granite residual soil(In Chinese).Rock and Soil Mechanics,2013,34(6):1668—1674
[5]周小文,刘攀,胡黎明,等.结构性花岗岩残积土的剪切屈服特性试验研究.岩土力学,2015,36(S2):157—163Zhou X W,Liu P,Hu L M,et al.The experimental research of shear and yield properties of structural granite residual soil(In Chinese).Rock and Soil Mechanics,2015,36(S2):157—163
[6]陈晓平,周秋娟,蔡晓英.高液限花岗岩残积土的物理特性和剪切特性.岩土工程学报,2011,33(6):901—908Chen X P,Zhou Q J,Cai X Y.Physical property and shear property of high liquid limit granite residual soil(In Chinese).Chinese Journal of Geotechnical Engineering,2011,33(6):901—908
[7]赵建军,王思敬,尚彦军,等.全风化花岗岩抗剪强度影响因素分析.岩土力学,2005,26(4):624—628Zhao J J,Wang S J,Shang Y J,et al.The effect factors analysis of completely weathered granite shear strength(In Chinese).Rock and Soil Mechanics,2005,26(4):624—628
[8]张丽萍,朱大奎,杨达源.长江三峡坝区花岗岩风化壳化学元素迁移特征.地理学报,2001,56(5):514—521Zhang L P,Zhu D K,Yang D Y.Chemical element transferring features of weathering granite regolith in Three Gorges Dam Region(In Chinese).Acta Geographica Sinica,2001,56(5):514—521
[9]齐岩辛,万治义,陈美君,等.浙江大明山花岗岩地貌景观特征与演化.科技通报,2016,32(2):66—70Qi Y X,Wan Z Y,Chen M J,et al.Granite landscape characteristics and evolution in Zhejiang Daming Mountain(In Chinese).Bulletin of Science and Technology,2016,32(2):66—70
[10]杨骏雄,刘丛强,赵志琦,等.不同气候带花岗岩风化过程中稀土元素的地球化学行为.矿物学报,2016,36(1):125—137Yang J X,Liu C Q,Zhao Z Q,et al.The geochemical behavior of rare earth elements of granite weathering process in different climatic zone(In Chinese).Acta Mineralogica Sinica,2016,36(1):125—137
[11]李建武,张甘霖,李德成,等.强烈风化条件下玄武岩发育土壤的元素地球化学特征.地球与环境,2012,40(4):491—498Li J W,Zhang G L,Li D C,et al.Basalt development soil elements geochemistry characteristics under strong weathering conditions(In Chinese).Earth and Environment,2012,40(4):491—498
[12]陈文,万渝生,李华芹,等.同位素地质年龄测定技术及应用.地质学报,2011,85(11):1917—1947Chen W,Wan Y S,Li H Q,et al.Isotope geological age determination technique and application(In Chinese).Acta Geologica Sinica,2011,85(11):1917—1947
[13]Guicharnaud R,Paton G I.An evaluation of acid deposition on cation leaching and weathering rates of an Andosol and a Cambisol.Journal of Geochemical Exploration,2006,88(1/3):279—283
[14]Riebe C S,Kirchner J W,Finkel R C.Long-term rates of chemical weathering and physical erosion from cosmogenic nuclides and geochemical mass balance.Geochimica et Cosmochimica Acta,2003,67(22):4411—4427
[15]黄成敏,龚子同.海南岛北部玄武岩上土壤发生研究Ⅲ.元素地球化学特征.土壤学报,2002,39(5):643—652Huang C M,Gong Z T.Study on genesis of soils derived from basalt in northern hainan islandⅢ.Element geochemistry(In Chinese).Acta Pedologica Sinica,2002,39(5):643—652
[16]张瑾,李德成,张甘霖,等.热带地区玄武岩发育时间序列土壤中石英颗粒微形态特征.土壤,2012,44(1):111—117Zhang J,Li D C,Zhang G L,et al.Quartz particles micro-morphological features in the soil of basalt development time series in the tropics(In Chinese).Soils,2012,44(1):111—117
[17]何跃,张甘霖.热带地区玄武岩发育土壤中的生物硅及其发生学意义.土壤学报,2010,47(3):385—392He Y,Zhang G L.Biological silicon and genetics significance in the soil of basalt development in the tropics(In Chinese).Acta Pedologica Sinica,2010,47(3):385—392
[18]杨金玲,张甘霖,黄来明.典型亚热带花岗岩地区森林流域岩石风化和土壤形成速率研究.土壤学报,2013,50(2):253—259Yang J L,Zhang G L,Huang L M.The research of rock weathering and in soil formation rate typical subtropical granite region forest basin(In Chinese).Acta Pedologica Sinica,2013,50(2):253—259
[19]张丽萍,杨达源,朱大奎.母岩的风化剥蚀速率与土壤允许流失量的关系—以长江三峡坝区风化花岗岩土壤为例.长江流域资源与环境,2003(4):382—387Zhang L P,Yang D Y,Zhu D K.The relationship between weathering denudation rate of the mother rock and soil loss tolerance—weathering granite soil in Three Gorges Dam Region as an example(In Chinese).Resources and Environment in the Yangtze Basin,2003(4):382—387
[20]刘成禹,何满潮.对岩石风化程度敏感的化学风化指数研究.地球与环境,2011,39(3):349—354Liu C Y,He M C.The research of sensitive chemical weathering index for the degree of rock weathering(In Chinese).Earth and Environment,2011,39(3):349—354
[2]宋全杰,李海波,李俊如,等.强风化花岗岩动力学参数的试验研究.岩土力学,2013,34(4):1031—1036Song Q J,Li H B,Li J R,et al.The experimental study of strong weathering granite kinetics parameters(In Chinese).Rock and Soil Mechanics,2013,34(4):1031—1036
[3]尚彦军,王思敬,岳中琦,等.全风化花岗岩孔径分布-颗粒组成-矿物成分变化特征及指标相关性分析.岩土力学,2004,25(10):1545—1550Shang Y J,Wang S J,Yue Z Q,et al.The correlation analysis of change features and indicators of pore distribution,particle composition and mineral component indicators of completely weathered granite(In Chinese).Rock and Soil Mechanics,2004,25(10):1545—1550
[4]张抒,唐辉明.非饱和花岗岩残积土崩解机制试验研究.岩土力学,2013,34(6):1668—1674Zhang S,Tang H M.The experimental research of disintegration mechanism of unsaturated granite residual soil(In Chinese).Rock and Soil Mechanics,2013,34(6):1668—1674
[5]周小文,刘攀,胡黎明,等.结构性花岗岩残积土的剪切屈服特性试验研究.岩土力学,2015,36(S2):157—163Zhou X W,Liu P,Hu L M,et al.The experimental research of shear and yield properties of structural granite residual soil(In Chinese).Rock and Soil Mechanics,2015,36(S2):157—163
[6]陈晓平,周秋娟,蔡晓英.高液限花岗岩残积土的物理特性和剪切特性.岩土工程学报,2011,33(6):901—908Chen X P,Zhou Q J,Cai X Y.Physical property and shear property of high liquid limit granite residual soil(In Chinese).Chinese Journal of Geotechnical Engineering,2011,33(6):901—908
[7]赵建军,王思敬,尚彦军,等.全风化花岗岩抗剪强度影响因素分析.岩土力学,2005,26(4):624—628Zhao J J,Wang S J,Shang Y J,et al.The effect factors analysis of completely weathered granite shear strength(In Chinese).Rock and Soil Mechanics,2005,26(4):624—628
[8]张丽萍,朱大奎,杨达源.长江三峡坝区花岗岩风化壳化学元素迁移特征.地理学报,2001,56(5):514—521Zhang L P,Zhu D K,Yang D Y.Chemical element transferring features of weathering granite regolith in Three Gorges Dam Region(In Chinese).Acta Geographica Sinica,2001,56(5):514—521
[9]齐岩辛,万治义,陈美君,等.浙江大明山花岗岩地貌景观特征与演化.科技通报,2016,32(2):66—70Qi Y X,Wan Z Y,Chen M J,et al.Granite landscape characteristics and evolution in Zhejiang Daming Mountain(In Chinese).Bulletin of Science and Technology,2016,32(2):66—70
[10]杨骏雄,刘丛强,赵志琦,等.不同气候带花岗岩风化过程中稀土元素的地球化学行为.矿物学报,2016,36(1):125—137Yang J X,Liu C Q,Zhao Z Q,et al.The geochemical behavior of rare earth elements of granite weathering process in different climatic zone(In Chinese).Acta Mineralogica Sinica,2016,36(1):125—137
[11]李建武,张甘霖,李德成,等.强烈风化条件下玄武岩发育土壤的元素地球化学特征.地球与环境,2012,40(4):491—498Li J W,Zhang G L,Li D C,et al.Basalt development soil elements geochemistry characteristics under strong weathering conditions(In Chinese).Earth and Environment,2012,40(4):491—498
[12]陈文,万渝生,李华芹,等.同位素地质年龄测定技术及应用.地质学报,2011,85(11):1917—1947Chen W,Wan Y S,Li H Q,et al.Isotope geological age determination technique and application(In Chinese).Acta Geologica Sinica,2011,85(11):1917—1947
[13]Guicharnaud R,Paton G I.An evaluation of acid deposition on cation leaching and weathering rates of an Andosol and a Cambisol.Journal of Geochemical Exploration,2006,88(1/3):279—283
[14]Riebe C S,Kirchner J W,Finkel R C.Long-term rates of chemical weathering and physical erosion from cosmogenic nuclides and geochemical mass balance.Geochimica et Cosmochimica Acta,2003,67(22):4411—4427
[15]黄成敏,龚子同.海南岛北部玄武岩上土壤发生研究Ⅲ.元素地球化学特征.土壤学报,2002,39(5):643—652Huang C M,Gong Z T.Study on genesis of soils derived from basalt in northern hainan islandⅢ.Element geochemistry(In Chinese).Acta Pedologica Sinica,2002,39(5):643—652
[16]张瑾,李德成,张甘霖,等.热带地区玄武岩发育时间序列土壤中石英颗粒微形态特征.土壤,2012,44(1):111—117Zhang J,Li D C,Zhang G L,et al.Quartz particles micro-morphological features in the soil of basalt development time series in the tropics(In Chinese).Soils,2012,44(1):111—117
[17]何跃,张甘霖.热带地区玄武岩发育土壤中的生物硅及其发生学意义.土壤学报,2010,47(3):385—392He Y,Zhang G L.Biological silicon and genetics significance in the soil of basalt development in the tropics(In Chinese).Acta Pedologica Sinica,2010,47(3):385—392
[18]杨金玲,张甘霖,黄来明.典型亚热带花岗岩地区森林流域岩石风化和土壤形成速率研究.土壤学报,2013,50(2):253—259Yang J L,Zhang G L,Huang L M.The research of rock weathering and in soil formation rate typical subtropical granite region forest basin(In Chinese).Acta Pedologica Sinica,2013,50(2):253—259
[19]张丽萍,杨达源,朱大奎.母岩的风化剥蚀速率与土壤允许流失量的关系—以长江三峡坝区风化花岗岩土壤为例.长江流域资源与环境,2003(4):382—387Zhang L P,Yang D Y,Zhu D K.The relationship between weathering denudation rate of the mother rock and soil loss tolerance—weathering granite soil in Three Gorges Dam Region as an example(In Chinese).Resources and Environment in the Yangtze Basin,2003(4):382—387
[20]刘成禹,何满潮.对岩石风化程度敏感的化学风化指数研究.地球与环境,2011,39(3):349—354Liu C Y,He M C.The research of sensitive chemical weathering index for the degree of rock weathering(In Chinese).Earth and Environment,2011,39(3):349—354