半干旱草原型流域表层土壤饱和导水率传递函数及遥感反演研究
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摘要
为了进一步探究遥感与表层土壤导水率的联系,以内蒙古锡林河流域为研究区,对厚栗黄土、草甸沼泽土、荒漠风沙土、石灰性草甸砂土、淡黑土5种土壤类型下的表层土壤进行采样,测定其粒径组成、容重、有机质、饱和导水率等理化特征。使用Saxton、Cosby、Wosten三种土壤饱和导水率传递函数及非线性多元经验回归模型对点尺度上0～30 cm表层土壤每10 cm土层的饱和导水率进行拟合,并利用这些点的土壤参数均值进行验证,结果显示Saxton模型效果最好,拟合及验证结果与实测值的拟合系数R~2分别为0.985、0.988。在此基础上,利用Radarsat-2四极化后向散射数据将模型中的表层土壤参数均值进行了8 m精度的面尺度扩展,并对遥感影像研究区范围内表层土壤饱和导水率进行预测。研究表明,土壤传递函数可以很好地刻画半干旱草原型流域表层土壤的饱和导水率,且土壤传递函数的结果与模型中包含的参数个数并不存在直接联系,人类活动对研究区表层土壤的饱和导水率影响极大。
【Objective】Remote sensing technology has successfully been applied to monitoring and inversion of soil parameters. In order to further promote application of the Synthetic Aperture Radar(SAR) technology to less-destructive soil monitoring and environmental management, based on the field survey and sampling, laboratory experiments and interpretation of microwave radar images, this study explored possibilities of inverting and predicting soil hydraulic parameters of semi-arid grassland basins on the premise of no large scaled damage.【Method】In this paper, the Xilin River Basin, Inner Mongolia was set as subject for the study. The study area had 5 major types of soils, i.e. Thick chestnut soil, Meadow swamp soil, Desert aeolian soil, Limy meadow sandy soil, and Pale black soil. From the surface layers of the soils, soil samples were collected for analysis of particle size composition, bulk density, organic matter content, saturated hydraulic conductivity(KS) and some other physical and chemical properties. First of all,distributions of soil parameters in soil layers, 10 cm each, of the five types of soils were characterized. Then Saxton, Cosby, and Wosten models, three saturated soil hydraulic conductivity pedo-transfer functions(PTFs)and nonlinear multivariate empirical regression models, were used for fitting of KS in soil layers, 10 cm each, within the 0～30 cm soil layers of the 32 sampling sites for modeling. Based on the averages of the soil parameters of these 32 sampling sites for modeling and backscattering of quadrupolarized Radarsat-2,a multivariate linear equation was established, using the radar data of the 10 sampling sites for validation to validate the fitting of KS.【Result】Results show that the study area is extremely high in soil sand content, almost nil in clay content and low in organic matter content. The parameters do not vary much with soil depth from layer to layer. In terms of PTFs, the four models reach 0.778, 0.985, 0.958, and 0.966 in modeling accuracy separately. Among them, Saxton model is the highest, with RMSE being 0.262 and layer average validation accuracy reaching 0.989. In terms of inversion of surface soil parameters based on back scattering coefficient of quadrupolarized RADARSAT-2, the inversions of bulk density and sand content are the best. In using the backscattering coefficient of the 10 validating sampling sites to validate PTFs,Saxton model is superior in fitting, with simulation coefficient reaching as high as 0.964. Consequently,this study has finally chosen Saxton model to predict surface soil saturated hydraulic conductivity on an 8 meter precision extended scale based on remote-sensing images of the study area, by combining Radarsat-2 radar data.【Conclusion】All the findings indicate that compared with inversion directly using SAR to predict surface soil KS in a large-scale, PTFs may better depict saturated conductivity of the surface soil layer in semi-arid grassland watersheds. However, the effect of PTFs are not directly related to the number of parameters contained in the model. Surface soil KS in the degraded grassland varies generally in the range of 4～8 m·d-1. Under natural conditions, the region lacks vegetation and high in sand content, which are the main reasons for rapid water transfer. In developed areas, like irrigation zones or urbanized regions, surface soil KS declines by a large margin, indicating that human activity is one of the main influencing factors of its change. The use of remote sensing to predict surface soil KS over a region is still not fully developed, so more efforts should be done to perfect and validate it.
【Objective】Remote sensing technology has successfully been applied to monitoring and inversion of soil parameters. In order to further promote application of the Synthetic Aperture Radar(SAR) technology to less-destructive soil monitoring and environmental management, based on the field survey and sampling, laboratory experiments and interpretation of microwave radar images, this study explored possibilities of inverting and predicting soil hydraulic parameters of semi-arid grassland basins on the premise of no large scaled damage.【Method】In this paper, the Xilin River Basin, Inner Mongolia was set as subject for the study. The study area had 5 major types of soils, i.e. Thick chestnut soil, Meadow swamp soil, Desert aeolian soil, Limy meadow sandy soil, and Pale black soil. From the surface layers of the soils, soil samples were collected for analysis of particle size composition, bulk density, organic matter content, saturated hydraulic conductivity(KS) and some other physical and chemical properties. First of all,distributions of soil parameters in soil layers, 10 cm each, of the five types of soils were characterized. Then Saxton, Cosby, and Wosten models, three saturated soil hydraulic conductivity pedo-transfer functions(PTFs)and nonlinear multivariate empirical regression models, were used for fitting of KS in soil layers, 10 cm each, within the 0～30 cm soil layers of the 32 sampling sites for modeling. Based on the averages of the soil parameters of these 32 sampling sites for modeling and backscattering of quadrupolarized Radarsat-2,a multivariate linear equation was established, using the radar data of the 10 sampling sites for validation to validate the fitting of KS.【Result】Results show that the study area is extremely high in soil sand content, almost nil in clay content and low in organic matter content. The parameters do not vary much with soil depth from layer to layer. In terms of PTFs, the four models reach 0.778, 0.985, 0.958, and 0.966 in modeling accuracy separately. Among them, Saxton model is the highest, with RMSE being 0.262 and layer average validation accuracy reaching 0.989. In terms of inversion of surface soil parameters based on back scattering coefficient of quadrupolarized RADARSAT-2, the inversions of bulk density and sand content are the best. In using the backscattering coefficient of the 10 validating sampling sites to validate PTFs,Saxton model is superior in fitting, with simulation coefficient reaching as high as 0.964. Consequently,this study has finally chosen Saxton model to predict surface soil saturated hydraulic conductivity on an 8 meter precision extended scale based on remote-sensing images of the study area, by combining Radarsat-2 radar data.【Conclusion】All the findings indicate that compared with inversion directly using SAR to predict surface soil KS in a large-scale, PTFs may better depict saturated conductivity of the surface soil layer in semi-arid grassland watersheds. However, the effect of PTFs are not directly related to the number of parameters contained in the model. Surface soil KS in the degraded grassland varies generally in the range of 4～8 m·d-1. Under natural conditions, the region lacks vegetation and high in sand content, which are the main reasons for rapid water transfer. In developed areas, like irrigation zones or urbanized regions, surface soil KS declines by a large margin, indicating that human activity is one of the main influencing factors of its change. The use of remote sensing to predict surface soil KS over a region is still not fully developed, so more efforts should be done to perfect and validate it.
引文
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[2]Zou G H,Li Y,Wang Y,et al.Pedo-transfer functions for estimating the hydraulic properties of paddy soils in subtropical central China.Archives of Agronomy and Soil Science,2016,62(7):982-993
[3]姚娇转,刘廷玺,王天帅,等.科尔沁沙地土壤水分特征曲线传递函数的构建与评估.农业工程学报,2014,30(20):98-108Yao J Z,Liu T X,Wang T S,et al.Development and evaluation of pedo-transfer functions of soil water characteristic curves in Horqin sandy land(In Chinese).Transactions of the Chinese Society of Agricultural Engineering,2014,30(20):98-108
[4]黄元仿,李韵珠.土壤水力性质的估算土壤转换函数.土壤学报,2002,39(4):517-523Huang Y F,Li Y Z.Estimation of soil hydraulic properties pedo-transfer functions(In Chinese).Acta Pedologica Sinica,2002,39(4):517-523
[5]Xu L,He N P,Yu G R,et al.Methods of evaluating soil bulk density:Impact on estimating large scale soil organic carbon storage.Catena,2016,144:94-121
[6]Aimrun W,Amin M S M.Pedo-transfer function for saturated hydraulic conductivity of lowland paddy soils.Paddy and Water Environment,2016,7(3):217-225
[7]Xu C H,Xu X L,Liu M X,et al.Enhancing pedotransfer functions(PTFs)using soil spectral reflectance data for estimating saturated hydraulic conductivity in southwestern China.Catena,2017,158:350-356
[8]李震,廖静娟,等.合成孔径雷达地表参数反演模型与方法.北京:科学出版社,2011Li Z,Liao J J,et al.Surface parameter inversion model and method of SAR(In Chinese).Beijing:Science Press,2011
[9]Sepuru T K,Dube T.An appraisal on the progress of remote sensing applications in soil erosion mapping and monitoring.Remote Sensing Applications:Society and Environment,2018,9:1-9
[10]Stamenkovic J,Guerriero L,Ferrazzoli P,et al.Soil moisture estimation by SAR in Alpine fields using Gaussian Process Regressor trained by Model Simulations.IEEE Transactions on Geoscience and Remote Sensing,2017,55(9):4899-4912
[11]Bertoldi G,Chiesa S D,Notamicola C,et al.Estimation of soil moisture patterns in mountain grasslands by means of SAR Radarsat2 images and hydrological modeling.Journal of Hydrology,2014,516(6):245-257
[12]Pasolli L,Notarnicola C,Bertoldi G,et al.Estimation of soil moisture in mountain areas using SVR technique applied to Multiscale active radar images at C-Band.IEEE Journal of Selected Topics in Applied Earth Observations&Remote Sensing,2015,8(1):262-283
[13]李杨,贾德彬,朱仲元,等.融雪的水量平衡模型在内蒙古锡林河流域水文模拟中的应用.水资源与水工程学报,2012,23(5):138-141Li Y,Jia D B,Zhu Z Y,et al.Hydrological simulation of Xil inhe River Bas in in Inner-Mongolia using snowmelt-based water balance model(In Chinese).Journal of Water Resources&Water Engineering,2012,23(5):138-141
[14]段利民,李玮,刘廷玺,等.半干旱草原型流域径流变化特征及其影响因子定量分析.干旱区资源与环境,2017,31(10):125-130Duan L M,Li W,Liu T X,et al.Runoff variation and driven factors qualification for a semi-arid steppe watershed(In Chinese).Journal of Arid Land Resources and Environment,2017,31(10):125-130
[15]Li W,Duan L M,Luo Y Y,et al.Spatiotemporal characteristics of extreme precipitation regimes in the eastern Inland River Basin of Inner Mongolian Plateau,China.Water,2018,10(1):1-16
[16]Cosby B J,Hornberger G M,Clapp R B,et al.A statistical exploration of the relationships of soil moisture characteristics to the physical properties of soils.Water Resources Research,1984,20(6):682-690
[17]Saxton K E,Rawls W J,Romberger J S,et al.Estimating generalized soil water characteristics from texture.Soil Science Society of America Journal,1986,50(4):1031-1036
[18]Wosten J H M.Pedo-transfer functions to evaluate soil quality//Gregorich E G,Carter M R.Soil quality for crop production and ecosystem health.Amsterdam:Elsevier Science Publishers,1997:221-245
[19]孙丽,刘廷玺,段利民,等.科尔沁沙丘-草甸相同地区表土饱和导水率的土壤传递函数研究.土壤学报,2015,52(1):68-76Sun L,Liu T X,Duan L M,et al.Prediction of saturated hydraulic conductivity of surface soil in sand-dune-and-meadow interland region of Horqin with pedo-transfer functions method(In Chinese).Acta Pedologica Sinica,2015,52(1):68-76
[20]Zhang J,Zuo X A,Zhou X,et al.Long-term grazing e ff e c t s o n v e g e t a t i o n c h a r a c t e r i s t i c s a n d s o i l properties in a semiarid grassland,northern China.Environmental Monitoring&Assessment,2017,189(5):1-13
[21]Yu Y,Wei W,Chen L D,et al.Land preparation and vegetation type jointly determine soil conditions after long-term land stabilization measures in a typical hilly catchment,Loess Plateau of China.Journal of Soils and Sediments,2017,17(1):144-156
[22]Mermoud A,Xu D.Comparative analysis of three methods to generate soil hydraulic functions.Soil&Tillage Research,2006,87(1):89-100
[23]Zimmermann E D,Basile P A.Estimation of hydraulic parameters in silty soils using different pedotransfer functions.Tecnologia Y Ciencias Del Agua,2011,2(1):99-116
[24]Medina H,Chirico G B,Romano N.Uncertainty in predicting soil hydraulic properties at the hillslope scale with indirect methods.Journal of Hydrology,2007,334(3):405-422
[25]Huang M B,Fredlund D G,Fredlund M D.Comparison of measured and PTF predictions of SWCCs for loess soils in China.Geotechnical and Geological Engineering,2010,28(2):105-117
[26]Wang Y,Gao G Y,Yang J,et al.Transient dynamic response of a shallow buried lined tunnel in saturated soil.Soil Dynamics and Earthquake Engineering,2017,94:13-17
[27]王子龙,赵勇钢,赵世伟,等.退耕典型草地土壤饱和导水率及其影响因素研究.草地学报,2016,24(6):1254-1262Wang Z L,Zhao Y G,Zhao S W,et al.Study on soil saturated hydraulic conductivity and its influencing factors in typical grassland of farmland conversion(In Chinese).Acta Agrestia Sinica,2016,24(6):1254-1262
[28]Bian H B,Isam S,Jia Y.Influence of soil saturation on the free field response of liquefiable soils.Underground Space,2017,2(1):30-37
[29]Buccigrossi F,Caliandro A,Rubino P,et al.Testing some pedo-t ransfer funct ions(PTFs)in Apul ia Region.Evaluation on the basis of soil particle size distribution and organic matter content for estimating field capacity and wilting point.Italian Journal of Agronomy,2010,5(4):367-382
[30]Millard K,Richardson M.Quantifying the relative contributions of vegetation and soil moisture conditions to polarimetric C-Band SAR response in a temperate peatland.Remote Sensing of Environment,2018,206(1):123-138
[31]Liao J J,Xu T,Shen G Z.Simulating microwave scattering for wetland vegetation in Poyang Lake,Southeast China,Using a Coherent Scattering Model.Remote Sensing,2015,7(8):9796-9821
[2]Zou G H,Li Y,Wang Y,et al.Pedo-transfer functions for estimating the hydraulic properties of paddy soils in subtropical central China.Archives of Agronomy and Soil Science,2016,62(7):982-993
[3]姚娇转,刘廷玺,王天帅,等.科尔沁沙地土壤水分特征曲线传递函数的构建与评估.农业工程学报,2014,30(20):98-108Yao J Z,Liu T X,Wang T S,et al.Development and evaluation of pedo-transfer functions of soil water characteristic curves in Horqin sandy land(In Chinese).Transactions of the Chinese Society of Agricultural Engineering,2014,30(20):98-108
[4]黄元仿,李韵珠.土壤水力性质的估算土壤转换函数.土壤学报,2002,39(4):517-523Huang Y F,Li Y Z.Estimation of soil hydraulic properties pedo-transfer functions(In Chinese).Acta Pedologica Sinica,2002,39(4):517-523
[5]Xu L,He N P,Yu G R,et al.Methods of evaluating soil bulk density:Impact on estimating large scale soil organic carbon storage.Catena,2016,144:94-121
[6]Aimrun W,Amin M S M.Pedo-transfer function for saturated hydraulic conductivity of lowland paddy soils.Paddy and Water Environment,2016,7(3):217-225
[7]Xu C H,Xu X L,Liu M X,et al.Enhancing pedotransfer functions(PTFs)using soil spectral reflectance data for estimating saturated hydraulic conductivity in southwestern China.Catena,2017,158:350-356
[8]李震,廖静娟,等.合成孔径雷达地表参数反演模型与方法.北京:科学出版社,2011Li Z,Liao J J,et al.Surface parameter inversion model and method of SAR(In Chinese).Beijing:Science Press,2011
[9]Sepuru T K,Dube T.An appraisal on the progress of remote sensing applications in soil erosion mapping and monitoring.Remote Sensing Applications:Society and Environment,2018,9:1-9
[10]Stamenkovic J,Guerriero L,Ferrazzoli P,et al.Soil moisture estimation by SAR in Alpine fields using Gaussian Process Regressor trained by Model Simulations.IEEE Transactions on Geoscience and Remote Sensing,2017,55(9):4899-4912
[11]Bertoldi G,Chiesa S D,Notamicola C,et al.Estimation of soil moisture patterns in mountain grasslands by means of SAR Radarsat2 images and hydrological modeling.Journal of Hydrology,2014,516(6):245-257
[12]Pasolli L,Notarnicola C,Bertoldi G,et al.Estimation of soil moisture in mountain areas using SVR technique applied to Multiscale active radar images at C-Band.IEEE Journal of Selected Topics in Applied Earth Observations&Remote Sensing,2015,8(1):262-283
[13]李杨,贾德彬,朱仲元,等.融雪的水量平衡模型在内蒙古锡林河流域水文模拟中的应用.水资源与水工程学报,2012,23(5):138-141Li Y,Jia D B,Zhu Z Y,et al.Hydrological simulation of Xil inhe River Bas in in Inner-Mongolia using snowmelt-based water balance model(In Chinese).Journal of Water Resources&Water Engineering,2012,23(5):138-141
[14]段利民,李玮,刘廷玺,等.半干旱草原型流域径流变化特征及其影响因子定量分析.干旱区资源与环境,2017,31(10):125-130Duan L M,Li W,Liu T X,et al.Runoff variation and driven factors qualification for a semi-arid steppe watershed(In Chinese).Journal of Arid Land Resources and Environment,2017,31(10):125-130
[15]Li W,Duan L M,Luo Y Y,et al.Spatiotemporal characteristics of extreme precipitation regimes in the eastern Inland River Basin of Inner Mongolian Plateau,China.Water,2018,10(1):1-16
[16]Cosby B J,Hornberger G M,Clapp R B,et al.A statistical exploration of the relationships of soil moisture characteristics to the physical properties of soils.Water Resources Research,1984,20(6):682-690
[17]Saxton K E,Rawls W J,Romberger J S,et al.Estimating generalized soil water characteristics from texture.Soil Science Society of America Journal,1986,50(4):1031-1036
[18]Wosten J H M.Pedo-transfer functions to evaluate soil quality//Gregorich E G,Carter M R.Soil quality for crop production and ecosystem health.Amsterdam:Elsevier Science Publishers,1997:221-245
[19]孙丽,刘廷玺,段利民,等.科尔沁沙丘-草甸相同地区表土饱和导水率的土壤传递函数研究.土壤学报,2015,52(1):68-76Sun L,Liu T X,Duan L M,et al.Prediction of saturated hydraulic conductivity of surface soil in sand-dune-and-meadow interland region of Horqin with pedo-transfer functions method(In Chinese).Acta Pedologica Sinica,2015,52(1):68-76
[20]Zhang J,Zuo X A,Zhou X,et al.Long-term grazing e ff e c t s o n v e g e t a t i o n c h a r a c t e r i s t i c s a n d s o i l properties in a semiarid grassland,northern China.Environmental Monitoring&Assessment,2017,189(5):1-13
[21]Yu Y,Wei W,Chen L D,et al.Land preparation and vegetation type jointly determine soil conditions after long-term land stabilization measures in a typical hilly catchment,Loess Plateau of China.Journal of Soils and Sediments,2017,17(1):144-156
[22]Mermoud A,Xu D.Comparative analysis of three methods to generate soil hydraulic functions.Soil&Tillage Research,2006,87(1):89-100
[23]Zimmermann E D,Basile P A.Estimation of hydraulic parameters in silty soils using different pedotransfer functions.Tecnologia Y Ciencias Del Agua,2011,2(1):99-116
[24]Medina H,Chirico G B,Romano N.Uncertainty in predicting soil hydraulic properties at the hillslope scale with indirect methods.Journal of Hydrology,2007,334(3):405-422
[25]Huang M B,Fredlund D G,Fredlund M D.Comparison of measured and PTF predictions of SWCCs for loess soils in China.Geotechnical and Geological Engineering,2010,28(2):105-117
[26]Wang Y,Gao G Y,Yang J,et al.Transient dynamic response of a shallow buried lined tunnel in saturated soil.Soil Dynamics and Earthquake Engineering,2017,94:13-17
[27]王子龙,赵勇钢,赵世伟,等.退耕典型草地土壤饱和导水率及其影响因素研究.草地学报,2016,24(6):1254-1262Wang Z L,Zhao Y G,Zhao S W,et al.Study on soil saturated hydraulic conductivity and its influencing factors in typical grassland of farmland conversion(In Chinese).Acta Agrestia Sinica,2016,24(6):1254-1262
[28]Bian H B,Isam S,Jia Y.Influence of soil saturation on the free field response of liquefiable soils.Underground Space,2017,2(1):30-37
[29]Buccigrossi F,Caliandro A,Rubino P,et al.Testing some pedo-t ransfer funct ions(PTFs)in Apul ia Region.Evaluation on the basis of soil particle size distribution and organic matter content for estimating field capacity and wilting point.Italian Journal of Agronomy,2010,5(4):367-382
[30]Millard K,Richardson M.Quantifying the relative contributions of vegetation and soil moisture conditions to polarimetric C-Band SAR response in a temperate peatland.Remote Sensing of Environment,2018,206(1):123-138
[31]Liao J J,Xu T,Shen G Z.Simulating microwave scattering for wetland vegetation in Poyang Lake,Southeast China,Using a Coherent Scattering Model.Remote Sensing,2015,7(8):9796-9821