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Detecting soil salinity with arid fraction integrated index and salinity index in feature space using Landsat TM imagery 被引量:14
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作者 Fei WANG Xi CHEN +2 位作者 GePing LUO JianLi DING XianFeng CHEN 《Journal of Arid Land》 SCIE CSCD 2013年第3期340-353,共14页
Modeling soil salinity in an arid salt-affected ecosystem is a difficult task when using remote sensing data because of the complicated soil context (vegetation cover, moisture, surface roughness, and organic matter... Modeling soil salinity in an arid salt-affected ecosystem is a difficult task when using remote sensing data because of the complicated soil context (vegetation cover, moisture, surface roughness, and organic matter) and the weak spectral features of salinized soil. Therefore, an index such as the salinity index (SI) that only uses soil spectra may not detect soil salinity effectively and quantitatively. The use of vegetation reflectance as an indirect indicator can avoid limitations associated with the direct use of soil reflectance. The normalized difference vegetation index (NDVI), as the most common vegetation index, was found to be responsive to salinity but may not be available for retrieving sparse vegetation due to its sensitivity to background soil in arid areas. Therefore, the arid fraction integrated index (AFⅡ) was created as supported by the spectral mixture analysis (SMA), which is more appropriate for analyzing variations in vegetation cover (particularly halophytes) than NDVI in the study area. Using soil and vegetation separately for detecting salinity perhaps is not feasible. Then, we developed a new and operational model, the soil salinity detecting model (SDM) that combines AFⅡ and SI to quantitatively estimate the salt content in the surface soil. SDMs, including SDM1 and SDM2, were constructed through analyzing the spatial characteristics of soils with different salinization degree by integrating AFⅡ and SI using a scatterplot. The SDMs were then compared to the combined spectral response index (COSRI) from field measurements with respect to the soil salt content. The results indicate that the SDM values are highly correlated with soil salinity, in contrast to the performance of COSRI. Strong exponential relationships were observed between soil salinity and SDMs (R2〉0.86, RMSE〈6.86) compared to COSRI (R2=0.71, RMSE=16.21). These results suggest that the feature space related to biophysical properties combined with AFII and SI can effectively provide information on soil salinity. 展开更多
关键词 soil salinity spectrum HALOPHYTES Landsat TM spectral mixture analysis feature space model
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A Method of Soil Salinization Information Extraction with SVM Classification Based on ICA and Texture Features 被引量:3
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作者 ZHANG Fei TASHPOLAT Tiyip +5 位作者 KUNG Hsiang-te DING Jian-li MAMAT.Sawut VERNER Johnson HAN Gui-hong GUI Dong-wei 《Agricultural Science & Technology》 CAS 2011年第7期1046-1049,1074,共5页
Salt-affected soils classification using remotely sensed images is one of the most common applications in remote sensing,and many algorithms have been developed and applied for this purpose in the literature.This stud... Salt-affected soils classification using remotely sensed images is one of the most common applications in remote sensing,and many algorithms have been developed and applied for this purpose in the literature.This study takes the Delta Oasis of Weigan and Kuqa Rivers as a study area and discusses the prediction of soil salinization from ETM +Landsat data.It reports the Support Vector Machine(SVM) classification method based on Independent Component Analysis(ICA) and Texture features.Meanwhile,the letter introduces the fundamental theory of SVM algorithm and ICA,and then incorporates ICA and texture features.The classification result is compared with ICA-SVM classification,single data source SVM classification,maximum likelihood classification(MLC) and neural network classification qualitatively and quantitatively.The result shows that this method can effectively solve the problem of low accuracy and fracture classification result in single data source classification.It has high spread ability toward higher array input.The overall accuracy is 98.64%,which increases by10.2% compared with maximum likelihood classification,even increases by 12.94% compared with neural net classification,and thus acquires good effectiveness.Therefore,the classification method based on SVM and incorporating the ICA and texture features can be adapted to RS image classification and monitoring of soil salinization. 展开更多
关键词 Independent component analysis(ICA) Texture features Support vector machine(SVM) soil salinizaiton
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Different Feature Selection of Soil Attributes Influenced Clustering Performance on Soil Datasets 被引量:1
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作者 Jiaogen Zhou Yang Wang 《International Journal of Geosciences》 2019年第10期919-929,共11页
Feature selection is very important to obtain meaningful and interpretive clustering results from a clustering analysis. In the application of soil data clustering, there is a lack of good understanding of the respons... Feature selection is very important to obtain meaningful and interpretive clustering results from a clustering analysis. In the application of soil data clustering, there is a lack of good understanding of the response of clustering performance to different features subsets. In the present paper, we analyzed the performance differences between k-means, fuzzy c-means, and spectral clustering algorithms in the conditions of different feature subsets of soil data sets. The experimental results demonstrated that the performances of spectral clustering algorithm were generally better than those of k-means and fuzzy c-means with different features subsets. The feature subsets containing environmental attributes helped to improve clustering performances better than those having spatial attributes and produced more accurate and meaningful clustering results. Our results demonstrated that combination of spectral clustering algorithm with the feature subsets containing environmental attributes rather than spatial attributes may be a better choice in applications of soil data clustering. 展开更多
关键词 feature Selection K-MEANS CLUSTERING Fuzzy C-MEANS CLUSTERING Spectral CLUSTERING soil Attributes
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Effects of Soil and Rock Mineralogy on Soil Erosion Features in the Merek Watershed, Iran 被引量:1
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作者 Mosayeb Heshmati Nik M. Majid +2 位作者 Shamshuddin Jusop Mohamad Gheitury Arifin Abdu 《Journal of Geographic Information System》 2013年第3期248-257,共10页
Accelerated soil erosion is anthropogenic phenomenon and a major worldwide environmental problem. It mainly leads to removal of the clay minerals and soil nutrients and thereby reduces soil fertility because of minera... Accelerated soil erosion is anthropogenic phenomenon and a major worldwide environmental problem. It mainly leads to removal of the clay minerals and soil nutrients and thereby reduces soil fertility because of mineralogical influence on the soil. The objectives of this study were to identify the dominant soil and rock minerals and the influences of mineralogical properties on soil erosion features. This study was conducted at the Merek watershed, located in Kermanshah, Iran. There are different geological formations comprising limestone, sandstone, radiolarite, flysch, shale and marl. The border of each formation was mapped based on geology map and was checked in the field, using GPS and digitized by GIS software (ILWIS 3.5). The erosion feature map was prepared through remotely sensed data (Landsat ETM+ 2002, Path/Row and acquired date). About 300 soil and 28 rock samples were collected from the study area for soil and mineralogy analysis. Result shows that inter-rill, rill and snow erosion were occurred mainly at soil from Sarvak, Ilam and Gurpi Formation which are mainly containing calcite, dolomite, quartz and caolinite minerals giving moderate soil erosion intensity (5 - 10 t·ha–1·yr–1). Whereas mica/smectite was dominant clay mineral of soil from Older Terraces resulting in gully erosion and considerable 12.90 t·ha–1·yr–1 soil loss. Furthermore, smectite was found as the dominant clay mineral from both soil and parent material of Kashkan Formation (marls material) contributing to landslide occurrence and severe annual soil erosion (16.6 t·ha–1·yr–1). This study revealed that both soil erosion feature and intensity potentially are affected by mineralogical properties. 展开更多
关键词 EROSION feature Merek WATERSHED soil MINERALOGY X-RAY Diffractogram
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Microorganisms in Small Patterned Ground Features and Adjacent Vegetated Soils along Topographic and Climatic Gradients in the High Arctic, Canada 被引量:1
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作者 Grizelle González Francisco J. Rivera-Figueroa +2 位作者 William A. Gould Sharon A. Cantrell José R. Pérez-Jiménez 《Open Journal of Soil Science》 2014年第1期47-55,共9页
In this study, we determine differences in total biomass of soil microorganisms and community structure (using the most probable number of bacteria (MPN) and the number of fungal genera) in patterned ground features (... In this study, we determine differences in total biomass of soil microorganisms and community structure (using the most probable number of bacteria (MPN) and the number of fungal genera) in patterned ground features (PGF) and adjacent vegetated soils (AVS) in mesic sites from three High Arctic islands in order to characterize microbial dynamics as affected by cryoturbation, and a broad bioclimatic gradient. We also characterize total biomass of soil microorganisms and the most probable number of bacteria along a topographic gradient within each bioclimatic subzone to evaluate whether differences in topography lead to differences in microbial dynamics at a smaller scale. We found total microbial biomass C, the most probable number of heterotrophic bacteria, and fungal genera vary along this bioclimatic gradient. Microbial biomass C decreased with increasing latitude. Overall, microbial biomass C, MPN and the number of fungal isolates were higher in AVS than in PGFs. The effects which topographic position had on microbial biomass C varied across the bioclimatic gradient as there was no effect of topographic position in Isachsen (subzone A) and Mould Bay (subzone B), when compared to Green Cabin (subzone C, warmer site).There was no effect of topographic position on MPN counts at Mould Bay and Green Cabin. However, in Isachsen, MPN counts were highest in the wet topographic position as compared to the mesic and dry. In conclusion, PGFs seem to decouple the effect climate that might have on the total biomass of soil microorganisms along the bioclimatic gradient;and influence gets ameliorated as latitude increases. Similarly, the effect of topography on the total microbial biomass is significant at the warmest bioclimatic zone of the gradient. Thus, climate and topographic effects on total microbial biomass increase with warmer climate. 展开更多
关键词 soil MICROORGANISMS High Artic CANADA Patterned featureS MICROBIAL Biomass
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Improving model performance in mapping cropland soil organic matter using time-series remote sensing data
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作者 Xianglin Zhang Jie Xue +5 位作者 Songchao Chen Zhiqing Zhuo Zheng Wang Xueyao Chen Yi Xiao Zhou Shi 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2024年第8期2820-2841,共22页
Faced with increasing global soil degradation,spatially explicit data on cropland soil organic matter(SOM)provides crucial data for soil carbon pool accounting,cropland quality assessment and the formulation of effect... Faced with increasing global soil degradation,spatially explicit data on cropland soil organic matter(SOM)provides crucial data for soil carbon pool accounting,cropland quality assessment and the formulation of effective management policies.As a spatial information prediction technique,digital soil mapping(DSM)has been widely used to spatially map soil information at different scales.However,the accuracy of digital SOM maps for cropland is typically lower than for other land cover types due to the inherent difficulty in precisely quantifying human disturbance.To overcome this limitation,this study systematically assessed a framework of“information extractionfeature selection-model averaging”for improving model performance in mapping cropland SOM using 462 cropland soil samples collected in Guangzhou,China in 2021.The results showed that using the framework of dynamic information extraction,feature selection and model averaging could efficiently improve the accuracy of the final predictions(R^(2):0.48 to 0.53)without having obviously negative impacts on uncertainty.Quantifying the dynamic information of the environment was an efficient way to generate covariates that are linearly and nonlinearly related to SOM,which improved the R^(2)of random forest from 0.44 to 0.48 and the R^(2)of extreme gradient boosting from 0.37to 0.43.Forward recursive feature selection(FRFS)is recommended when there are relatively few environmental covariates(<200),whereas Boruta is recommended when there are many environmental covariates(>500).The Granger-Ramanathan model averaging approach could improve the prediction accuracy and average uncertainty.When the structures of initial prediction models are similar,increasing in the number of averaging models did not have significantly positive effects on the final predictions.Given the advantages of these selected strategies over information extraction,feature selection and model averaging have a great potential for high-accuracy soil mapping at any scales,so this approach can provide more reliable references for soil conservation policy-making. 展开更多
关键词 CROPLAND soil organic matter digital soil mapping machine learning feature selection model averaging
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Environmental geochemical features of arsenic in soil in China
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《Journal of Environmental Sciences》 SCIE EI CAS CSCD 1997年第4期3-13,共11页
EnvironmentalgeochemicalfeaturesofarsenicinsoilinChinaWengHuanxin,LiuYunfengDepartmentofEarthSciences,Zhejia... EnvironmentalgeochemicalfeaturesofarsenicinsoilinChinaWengHuanxin,LiuYunfengDepartmentofEarthSciences,ZhejiangUniversity,Hang... 展开更多
关键词 soil Environmental geochemical features of arsenic in soil in China
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Effect of microrelief features of tillage methods under different rainfall intensities on runoff and soil erosion in slopes 被引量:1
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作者 Xinkai Zhao Xiaoyu Song +3 位作者 Lanjun Li Danyang Wang Pengfei Meng Huaiyou Li 《International Soil and Water Conservation Research》 SCIE CSCD 2024年第2期351-364,共14页
Tillage methods play a crucial role in controlling rainwater partitioning and soil erosion.This study utilized rainfall simulation experiments to investigate the impact of four tillage methods(manual digging(MD),manua... Tillage methods play a crucial role in controlling rainwater partitioning and soil erosion.This study utilized rainfall simulation experiments to investigate the impact of four tillage methods(manual digging(MD),manual hoeing(MH),traditional ploughing(TP),and ridged ploughing(RP))on runoff and soil erosion at the plot scale.The smooth slope(SS)was used as a benchmark.Rainfall intensities of 30,60,90,and 120 mm h−1 were considered.The study revealed that tillage altered rainwater distribution into depression storage,infiltration,and runoff.Tillage reduces runoff and increases infiltration.The four tillage methods(30–73%)increased the proportion of rainwater converted to infiltration to varying degrees compared to the SS(22–53%).Microrelief features influenced the role of tillage methods in soil erosion.Surface roughness and depression storage accounted for 79%of the variation in sediment yield.The four tillage methods reduced runoff by 2.1–64.7%and sediment yield by 2.5–77.2%.Moreover,increased rainfall intensity weakens the ability of tillage to control soil erosion.When rainfall intensity increased to 120 mm h−1,there was no significant difference in runoff yield among RP,TP,MH,and SS.Therefore,assessing the effectiveness of tillage in reducing soil erosion should consider changes in rainfall intensity.Additionally,the cover management(C)factor of the RUSLE was used to assess the effects of different tillage methods on soil loss.Overall,the C factor values for tilled slopes are in the order MH>TP>RP>MD with a range of 0.23–0.97.As the surface roughness increases,the C factor tends to decrease,and the two are exponential functions(R2=0.86).These studies contribute to our understanding of how different tillage methods impact runoff and soil erosion in sloped farmland and provide guidance for selecting appropriate local manual tillage methods. 展开更多
关键词 Simulated rainfall Tillage methods Microrelief features RUNOFF soil erosion
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The Formation Mechanism of Hydrogeochemical Features in a Karst System During Storm Events as Revealed by Principal Component Analysis
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作者 Pingheng Yang Daoxian Yuan Kuang Yinglun,Wenhao Yuan,Peng Jia,Qiufang He 1.School of Geographical Sciences,Southwest University,Chongqing 400715,China. 2.Laboratory of Geochemistry and Isotope,Southwest University,Chongqing 400715,China 3.The Karst Dynamics Laboratory,Ministry of Land and Resources,Institute of Karst Geology,Chinese Academy of Geological Sciences,Guilin 541004,China 《地学前缘》 EI CAS CSCD 北大核心 2009年第S1期33-34,共2页
The hydrogeochemical parameters of Jiangjia Spring,the outlet of Qingrnuguan underground river system(QURS) in Chongqing,were found responding rapidly to storm events in late April,2008.A total of 20 kinds of hydrogeo... The hydrogeochemical parameters of Jiangjia Spring,the outlet of Qingrnuguan underground river system(QURS) in Chongqing,were found responding rapidly to storm events in late April,2008.A total of 20 kinds of hydrogeochemical parameters,including discharge,specific conductance,pH,water tempera- 展开更多
关键词 RAINFALL principal component analysis(PCA) soil EROSION AGRICULTURAL activities KARST hydrogeochemical feature Qingmuguan
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Improved Soil Quality Prediction Model Using Deep Learning for Smart Agriculture Systems
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作者 P.Sumathi V.V.Karthikeyan +1 位作者 M.S.Kavitha S.Karthik 《Computer Systems Science & Engineering》 SCIE EI 2023年第5期1545-1559,共15页
Soil is the major source of infinite lives on Earth and the quality of soil plays significant role on Agriculture practices all around.Hence,the evaluation of soil quality is very important for determining the amount ... Soil is the major source of infinite lives on Earth and the quality of soil plays significant role on Agriculture practices all around.Hence,the evaluation of soil quality is very important for determining the amount of nutrients that the soil require for proper yield.In present decade,the application of deep learning models in many fields of research has created greater impact.The increasing soil data availability of soil data there is a greater demand for the remotely avail open source model,leads to the incorporation of deep learning method to predict the soil quality.With that concern,this paper proposes a novel model called Improved Soil Quality Prediction Model using Deep Learning(ISQP-DL).The work considers the chemical,physical and biological factors of soil in particular area to estimate the soil quality.Firstly,pH rating of soil samples has been collected from the soil testing laboratory from which the acidic range has been categorized through soil test and the same data has been taken as input to the Deep Neural Network Regression(DNNR)model.Secondly,soil nutrient data has been given as second input to the DNNR model.By utilizing this data set,the DNNR method is used to evaluate the fertility rate by which the soil quality has been estimated.For training and testing,the model uses Deep Neural Network Regression(DNNR),by utilizing the dataset.The results show that the proposed model is effective for SQP(Soil Quality Prediction Model)with efficient good fitting and generality is enhanced with input features with higher rate of classification accuracy.The results show that the proposed model achieves 96.7%of accuracy rate compared with existing models. 展开更多
关键词 soil quality CLASSIFICATION ACCURACY deep learning neural network soil features training and testing
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基于Sentinel-1/2改进极化指数和纹理特征的土壤含盐量反演模型 被引量:1
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作者 张智韬 贺玉洁 +3 位作者 殷皓原 项茹 陈俊英 杜瑞麒 《农业机械学报》 EI CAS CSCD 北大核心 2024年第1期175-185,共11页
目前Sentinel-1/2协同反演植被土壤含盐量的研究大多是基于Sentinel-2光谱信息和Sentinel-1后向散射系数,没有考虑Sentinel-2光谱信息容易受土壤亮度等信息影响,Sentinel-1后向散射系数容易受土壤粗糙度和水分影响。为进一步提高Sentine... 目前Sentinel-1/2协同反演植被土壤含盐量的研究大多是基于Sentinel-2光谱信息和Sentinel-1后向散射系数,没有考虑Sentinel-2光谱信息容易受土壤亮度等信息影响,Sentinel-1后向散射系数容易受土壤粗糙度和水分影响。为进一步提高Sentinel-1/2协同反演植被土壤含盐量的精度,用水云模型对雷达卫星后向散射系数进行校正,消除植被影响;然后协同Sentinel-2纹理特征,基于VIP、OOB、PCA 3种变量筛选和RF、ELM、Cubist 3种机器学习回归模型构建植被土壤含盐量反演模型。研究结果表明:经过水云模型去除植被影响后的雷达后向散射系数及其极化组合指数与土壤含盐量的相关性有一定程度的提高。不同变量选择方法与不同机器学习方法耦合模型在反演土壤含盐量中,OOB变量筛选方法与RF、ELM和Cubist 3种机器学习方法的耦合模型精度最佳,建模集和验证集的R2都在0.750以上,且验证集的RMSE和MAE均最小;其中OOB-Cubist耦合模型精度最高,且R_(v)^(2)/R_(c)^(2)为0.955,具有良好的鲁棒性。研究可为机器学习协同物理模型、光学卫星协同雷达卫星在土壤含盐量反演中的进一步应用提供思路。 展开更多
关键词 土壤含盐量 Sentinel-1/2 纹理特征 水云模型 机器学习 改进极化指数
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融合无人机光谱信息与纹理特征的大豆土壤含水率估测模型研究
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作者 李志军 陈国夫 +4 位作者 支佳伟 向友珍 李冬梅 张富仓 陈俊英 《农业机械学报》 EI CAS CSCD 北大核心 2024年第9期347-357,共11页
及时获取大田作物根区土壤含水率(Soil moisture content,SMC)对于实现精准灌溉至关重要。本研究采用无人机多光谱技术,通过连续2年(2021—2022年)田间试验,采集了大豆开花期不同土壤深度的SMC数据以及相应的无人机多光谱图像,建立了与... 及时获取大田作物根区土壤含水率(Soil moisture content,SMC)对于实现精准灌溉至关重要。本研究采用无人机多光谱技术,通过连续2年(2021—2022年)田间试验,采集了大豆开花期不同土壤深度的SMC数据以及相应的无人机多光谱图像,建立了与作物参数具有较强相关性的植被指数及冠层纹理特征。通过分析植被指数和纹理特征与各深度土层SMC的相关性,分别筛选出与各深度土层SMC相关系数达显著相关(P<0.05)的参数作为模型的输入变量(组合1:植被指数;组合2:纹理特征;组合3:植被指数结合纹理特征),分别利用支持向量机(Support vector machine,SVM)、梯度提升模型(Extreme gradient boosting,XGBoost)和梯度提升决策树(Gradient boosting decision tree,GDBT)对各深度土层SMC进行建模。结果表明,与20~40 cm和40~60 cm土层深度相比,植被指数和纹理特征在0~20 cm土层深度中与SMC表现出更高的相关性。XGBoost模型为SMC估算的最佳建模方法,特别是对于0~20 cm土层深度。该深度估计模型验证集决定系数为0.881,均方根误差为0.7%,平均相对误差为3.758%。本研究结果为大豆根区SMC无人机多光谱监测提供了基础,为水分胁迫条件下作物生长的快速评估提供了参考。 展开更多
关键词 大豆 土壤含水率 无人机 多光谱 植被指数 纹理特征
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Features of Tropical Volcanic Rock and Soil of Jakarta-Bandung HSR and Engineering Countermeasures
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作者 ZHAO Dou WANG Shujie ZHENG Mingda(Translated) 《Chinese Railways》 2024年第1期30-37,共8页
The geological features of three types of tropical volcanic rock and soil distributed along Jakarta-Bandung high-speed railway(HSR),including pozzolanic clayey soil,mud shale and deep soft soil,are studied through fie... The geological features of three types of tropical volcanic rock and soil distributed along Jakarta-Bandung high-speed railway(HSR),including pozzolanic clayey soil,mud shale and deep soft soil,are studied through field and laboratory tests.The paper analyzes the mechanism and causes of engineering geological problems caused by tropical volcanic rock and soil and puts forward measures to control subgrade slope instability by rationally determining project type,making side slope stability control and strengthening waterproofing and drainage.The“zero front slope”tunneling technology at the portal,the simplified excavation method of double-side wall heading and the cross brace construction method of arch protection within the semi-open cut row pile frame in the“mountainside”eccentrically loaded soft soil stratum are adopted to control the instability of tunnel side and front slopes,foundation pits and working faces;CFG or pipe piles shall be used to reinforce soft and expansive foundation or replacement measures shall be taken,and the scheme of blind ditch+double-layer water sealing in ballastless track section shall be put forward to prevent arching deformation of foundation;the treatment measures of CFG pile,pipe pile and vacuum combined piled preloading are adopted to improve the bearing capacity of foundation in deep soft soil section and solve the problems of settlement control and uneven settlement.These engineering countermeasures have been applied during the construction of Jakarta-Bandung HSR and achieved good results. 展开更多
关键词 Jakarta-Bandung HSR tropical volcanic rock and soil engineering geological features engineering geological problems engineering countermeasures
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基于特征变量筛选的无人机多光谱遥感土壤含水量反演
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作者 张成才 王蕊 +2 位作者 侯佳彤 姜明梁 祝星星 《中国农村水利水电》 北大核心 2024年第5期147-154,共8页
土壤含水量是影响农作物生长的重要因素之一,对作物估产和旱情监测具有重要作用。在土壤含水量反演时,一般是提取多个光谱变量进行反演,但变量之间包含的光谱信息可能存在冗余重叠,为提取有效特征变量,使其相互独立,论文选取特征变量筛... 土壤含水量是影响农作物生长的重要因素之一,对作物估产和旱情监测具有重要作用。在土壤含水量反演时,一般是提取多个光谱变量进行反演,但变量之间包含的光谱信息可能存在冗余重叠,为提取有效特征变量,使其相互独立,论文选取特征变量筛选方法,并验证其在土壤含水量反演中的适用性。研究基于无人机多光谱影像计算归一化植被指数(Normalized Difference Vegetation Index,NDVI)等12种植被指数,结合无人机热红外数据计算地表温度(Land Surface Temperature,LST)和对应温度植被干旱指数(Temperature Vegetation Dryness Index,TVDI),以及miniSAR数据处理得到的4种后向散射系数,采用XGBoost特征变量和最优子集选择算法(Best Subset Selection,BSS)筛选最优变量组合,然后利用偏最小二乘回归(Partial Least Squares Regression,PLSR)和随机森林回归(Random Forest Regression,RFR)算法反演实验区冬小麦抽穗期的土壤含水量。研究结果表明:①0~20 cm深度的反演结果均优于0~10 cm深度;②对比XGBoost-PLSR、XGBoost-RFR、BSS-PLSR以及BSS-RFR四种土壤含水量反演模型,BSS-RFR模型不同深度下的反演精度最高;③0~10 cm土壤深度下XGBoost-PLSR模型的反演精度优于XGBoost-RFR,0~20 cm深度下则两者相反,0~20 cm深度下,BSS-RFR模型的反演精度均高于BSS-PLSR。研究成果可为无人机多光谱遥感反演土壤含水量提供理论和技术支撑,为卫星遥感大范围土壤水分监测提供检验依据。 展开更多
关键词 土壤含水量 无人机 XGBoost特征筛选 最优子集选择 偏最小二乘回归 随机森林回归
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覆盖型岩溶区高速铁路综合选线研究
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作者 王俊冬 《山西建筑》 2024年第3期90-93,共4页
南玉高铁沿线覆盖型岩溶和膨胀岩(土)广泛发育,岩溶发育程度强烈,膨胀岩(土)多呈弱—中等膨胀性,给高速铁路勘察设计、施工运营全生命周期均带来较大风险和挑战。通过分析沿线地形地貌、特殊的岩溶地质特征和工程环境特点,提出针对性的... 南玉高铁沿线覆盖型岩溶和膨胀岩(土)广泛发育,岩溶发育程度强烈,膨胀岩(土)多呈弱—中等膨胀性,给高速铁路勘察设计、施工运营全生命周期均带来较大风险和挑战。通过分析沿线地形地貌、特殊的岩溶地质特征和工程环境特点,提出针对性的勘察方法和选线原则,前期选线贯彻“短距通过,傍山绕避”原则,针对确实无法绕避的岩溶强烈发育区,提出“双向跨越”思路,安全、经济地跨越深溶槽,以期为覆盖型岩溶区高速铁路勘察设计及工程建设提供借鉴。 展开更多
关键词 南玉高铁 工程地质特征 覆盖型岩溶 膨胀岩(土) 选线
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基于采样点光谱信息窗口尺度优化的土壤含水率无人机多光谱遥感反演 被引量:2
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作者 靳亚红 吴鑫淼 +3 位作者 甄文超 崔晓彤 陈丽 郄志红 《农业机械学报》 EI CAS CSCD 北大核心 2024年第1期316-327,共12页
针对空间异质性导致的土壤含水率反演误差较大的问题,分别以玉米灌浆期和小麦苗期的土壤含水率反演为例,利用无人机多光谱遥感技术获取喷灌和畦灌灌溉方式下的正射影像。将34组光谱特征变量按照滑动窗口法提取不同空间尺度的光谱信息平... 针对空间异质性导致的土壤含水率反演误差较大的问题,分别以玉米灌浆期和小麦苗期的土壤含水率反演为例,利用无人机多光谱遥感技术获取喷灌和畦灌灌溉方式下的正射影像。将34组光谱特征变量按照滑动窗口法提取不同空间尺度的光谱信息平均值,通过极端梯度提升(Extreme gradient boosting, XGBoost)、支持向量机回归(Support vector machine regression, SVR)以及偏最小二乘回归(Partial least squares regression, PLSR)3种机器学习模型确定采样点光谱信息最优窗口尺度;然后,采用皮尔逊相关系数特征变量筛选法(Pearson correlation coefficient feature variable screening method, R)结合XGBoost和SVR模型对提取的34组光谱特征变量进行筛选,选取与土壤含水率敏感的特征变量;最后,估算土壤含水率。结果表明:喷灌方式下所选择的采样点最优光谱信息窗口尺度比畦灌小,其最优窗口尺度范围分别为11×11~21×21和15×15~29×29;采用皮尔逊相关系数特征变量筛选方法结合机器学习模型可有效提高土壤含水率反演精度;5种机器学习模型(R_XGBoost、R_SVR、XGBoost、SVR、PLSR)中R_XGBoost模型估算土壤含水率精度最优,在喷灌和畦灌方式下玉米灌浆期R_XGBoost模型的测试集决定系数R2分别为0.80、0.83,均方根误差(Root mean square error, RMSE)分别为1.27%和0.98%,小麦苗期R2分别为0.76、0.79,RMSE分别为1.68%和0.85%;土壤含水率反演模型在畦灌条件下的精度优于喷灌条件下。该研究可为基于无人机多光谱影像分析的信息挖掘和土壤水分监测提供参考。 展开更多
关键词 土壤含水率 窗口尺度 无人机多光谱遥感 机器学习 特征变量 反演
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基于递归特征消除−随机森林模型的江浙沪农田土壤肥力属性制图 被引量:4
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作者 李安琪 杨琳 +4 位作者 蔡言颜 张磊 黄海莉 吴琪 王雯琪 《地理科学》 CSSCI CSCD 北大核心 2024年第1期168-178,共11页
以江苏省、浙江省、上海市农田为研究区,选用气候、地形、植被、土壤属性等自然环境协变量,及农业机械总动力、每公顷农用化肥施用量、农业总产值、农村用电量等农业活动变量,利用递归特征消除方法(RFE)对环境协变量进行筛选,基于筛选... 以江苏省、浙江省、上海市农田为研究区,选用气候、地形、植被、土壤属性等自然环境协变量,及农业机械总动力、每公顷农用化肥施用量、农业总产值、农村用电量等农业活动变量,利用递归特征消除方法(RFE)对环境协变量进行筛选,基于筛选后的最优变量组合建立随机森林(RF)模型,进行表层土壤pH、有机碳、全氮、全磷、全钾、铵态氮、硝态氮、有效磷、速效钾、交换性钙、交换性镁11种主要土壤肥力属性的空间分布预测,并采用100次重复的十折交叉验证法进行验证。结果表明:①11个模型筛选出的环境协变量类型主要集中在气候、地形与植被变量,表征人类农业活动的变量在有机碳、全磷、全钾、铵态氮和有效磷预测中体现重要作用。②11个模型的决定系数(R^(2))在0.27~0.53,pH、速效钾、交换性镁和交换性钙的预测模型决定系数(R^(2))均在0.45以上。本研究表明人类活动变量对于土壤肥力预测具有重要意义,而递归特征消除−随机森林模型(RFE-RF)可以用于农田主要土壤肥力属性制图,为农业生产提供准确的土壤肥力属性空间分布信息。 展开更多
关键词 递归特征消除 随机森林 土壤肥力属性 农田土壤 数字土壤制图 江浙沪
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基于特征筛选算法的数字土壤制图研究 被引量:1
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作者 张晓婷 黄魏 +2 位作者 傅佩红 孟可 王苏放 《土壤学报》 CAS CSCD 北大核心 2024年第3期635-647,共13页
平缓地带数字土壤制图中,环境协变量的选择是提高制图精度的关键。已有研究证明遥感影像可作为推理制图的辅助因子,而如何确定环境因子推理制图时各自的权重已成为现阶段研究的重点。选取湖北省麻城市乘马岗镇为研究区,采用3种特征筛选... 平缓地带数字土壤制图中,环境协变量的选择是提高制图精度的关键。已有研究证明遥感影像可作为推理制图的辅助因子,而如何确定环境因子推理制图时各自的权重已成为现阶段研究的重点。选取湖北省麻城市乘马岗镇为研究区,采用3种特征筛选方法进行有效环境变量筛选,探索参与平原-丘陵混合区域制图的因子并确定其重要性,依据选择的相对稳定的指标,进一步探索提高土壤类型制图准确性的途径。根据141个野外独立样点的检验结果表明:在推理制图中,遥感因子在平原区域的重要性程度高于丘陵区域,且遥感因子中归一化植被指数(NDVI)和均值(Mean)较为稳定;基于递归特征算法的按地形推理制图精度最高为75.89%,分别高于ReliefF算法和基于Tree的特征筛选算法13.48%和4.97%;此外3种特征筛选算法制图结果中,按地形因子分区制图的精度均高于整体区域制图。因此,遥感因子作为辅助手段参与推理过程可有效提高制图精度。本研究采用的特征挖掘与机器学习算法对提升土壤制图精度具有一定的理论意义。 展开更多
关键词 土壤-环境知识获取 特征筛选 数字土壤制图 贝叶斯优化 梯度提升树
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基于多时相土壤线一致性修正的土壤含水率反演
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作者 徐冉 文铭 +3 位作者 赵红莉 郝震 王镕 贺君彦 《农业工程学报》 EI CAS CSCD 北大核心 2024年第14期73-80,共8页
传统上依赖改进型垂直干旱指数(modified perpendicular dryness index,MPDI)进行土壤水分反演时每个时期的影像反演都需要依赖于地面实测数据进行校准。为降低土壤含水率反演对实测数据的依赖,该研究利用2020—2021年间的哨兵2号卫星数... 传统上依赖改进型垂直干旱指数(modified perpendicular dryness index,MPDI)进行土壤水分反演时每个时期的影像反演都需要依赖于地面实测数据进行校准。为降低土壤含水率反演对实测数据的依赖,该研究利用2020—2021年间的哨兵2号卫星数据,分析了近红外与红光波段特征空间中土壤线斜率的变化及其影响因素。并推导了土壤线斜率变化对土壤含水率反演的影响,揭示了MPDI反演土壤含水率时每期都依赖实测数据校准的根本原因,最终提出了一种土壤线一致性修正方法。基于这种修正,该研究构建了一个能够多时相比较的再修正干旱指数(re-modified perpendicular drought index,RPDI)。结果表明,经过统一率定的RPDI与土壤含水率的回归方程在不同时相的影像上均适用,反演结果显示了良好的精度,率定集决定系数R^(2)为0.49,无偏均方根误差为2.88%,验证集决定系数R^(2)为0.54,无偏均方根误差为3.05%,与MPDI每期单独构建回归方程反演相比,RPDI基于统一方程反演与其保持了相近的精度水平,极大减少了在遥感土壤含水率估算中对地面实测数据的依赖,有效提升了遥感技术在土壤水分监测中的应用价值。研究可为光学遥感数据在大范围连续土壤水分反演领域的应用研究提供参考。 展开更多
关键词 土壤含水率 修正 遥感 RPDI MPDI 特征空间 土壤线斜率
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基于SOFM与随机森林的大别山区水土保持空间管控分区
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作者 常耀文 杜晨曦 +4 位作者 刘霞 郭家瑜 张春强 黎家作 姚孝友 《农业工程学报》 EI CAS CSCD 北大核心 2024年第20期250-258,共9页
水土保持是国家生态文明建设的重要内容,水土保持空间管控分区是水土流失区域科学治理的前提与关键。然而,目前水土保持管控区域划分研究还未形成成熟的空间划定方法,且以小流域为单元的水土保持空间管控研究较少。为探索水土保持空间... 水土保持是国家生态文明建设的重要内容,水土保持空间管控分区是水土流失区域科学治理的前提与关键。然而,目前水土保持管控区域划分研究还未形成成熟的空间划定方法,且以小流域为单元的水土保持空间管控研究较少。为探索水土保持空间管控分区的方法,落实差别化保护治理措施,该研究利用通用土壤流失方程(universal soil loss equation,USLE)计算研究区潜在土壤侵蚀模数与实际土壤侵蚀模数,并通过随机森林确定了土壤侵蚀的主要影响因子,基于小流域单元的土壤侵蚀及其影响因子利用自组织映射神经网络(self-organizing feature map,SOFM)确定了大别山区的水土保持空间管控分区。结果显示:1)大别山区的平均潜在土壤侵蚀为84 415.7 t/(km^(2)·a),平均实际土壤侵蚀为210.25 t/(km^(2)·a)。小流域的实际土壤侵蚀主要分布于0~300 t/(km^(2)·a),小流域尺度上潜在土壤侵蚀与实际土壤侵蚀空间分布格局基本一致,高值区主要分布于研究区中部与东部海拔较高的山区腹地;2)植被覆盖度、坡度分别为小流域尺度上潜在土壤侵蚀与实际土壤侵蚀的主要影响因子,植被覆盖度、坡度与土壤侵蚀呈显著正相关(P<0.01)。高植被覆盖区主要分布于林地占比较高的大别山区腹地,坡度较大的区域沿大别山山脊线自西向东分布。3)SOFM结果显示,小流域尺度上的大别山水土保持空间管控区域划分为重点预防区、一般预防区与其他区域,其中重点预防区涉及小流域710个,面积15 287.4 km^(2)。一般预防区共890个小流域,面积18 874.4 km^(2)。两个预防区面积共占研究区61.2%。各区域间的实际土壤侵蚀、潜在土壤侵蚀与坡度差异明显,可作为大别山水土保持空间管控各区域的主要划分指标。研究结果为水土保持空间管控分区提供了思路,为分区域进行水土保持空间管控提供了理论支持与决策依据。 展开更多
关键词 土壤侵蚀 大别山区 SOFM 随机森林 水土保持空间管控
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