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为了建立面域三维土壤盐分信息精准解译与表征技术方法,该研究以反距离权重空间数据插值方法结合电磁感应式表观土壤电导率快速测定技术为基础,成功构建出典型干旱区土壤盐分分层精确解译模型,对研究区土壤盐分进行了精度解析与评估,以三维图形方式直观揭示了土壤盐分空间分布特征。研究区不同区位土壤盐分呈现出不同的剖面分布类型特征,研究区主体土壤属于中度以上盐渍化。该研究将为土壤盐分三维空间分布特征解析与评估提供可靠技术方法。 相似文献
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《Land Degradation u0026amp; Development》2018,29(6):1768-1781
To generate baseline data for the purpose of monitoring the efficacy of remediation of a degraded landscape, we demonstrate a method for 3‐dimensional mapping of electrical conductivity of saturated soil paste extract (ECe) across a study field in central Haryana, India. This is achieved by establishing a linear relationship between calculated true electrical conductivity (σ) and laboratory measured ECe at various depths (0–0.3, 0.3–0.6, 0.6–0.9, and 0.9–1.2 m). We estimate σ by inverting DUALEM‐21S apparent electrical conductivity (ECa) data using a quasi‐3‐dimensional inversion algorithm (EM4Soil‐V302). The best linear relationship (ECe = −11.814 + 0.043 × σ) was achieved using full solution (FS), S1 inversion algorithm, and a damping factor (λ) of 0.6 that had a large coefficient of determination (R2 = 0.84). A cross‐validation technique was used to validate the model, and given the high accuracy (RMSE = 8.31 dS m−1), small bias (mean error = −0.0628 dS m−1), large R2 = 0.82, and Lin's concordance (0.93), between measured and predicted ECe, we were well able to predict the ECe distribution at all the four depths. However, the predictions made in the topsoil (0–0.3 m) at a few locations were poor due to limited data availability in areas where ECa changed rapidly. In this regard, improvements in prediction can be achieved by collection of ECa in more closely spaced transects, particularly in areas where ECa varies over short spatial scales. Also, equivalent results can be achieved using smaller combinations of ECa data (i.e., DAULEM‐1S, DUALEM‐2S), although with some loss in precision, bias, and concordance. 相似文献
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Mohammad Farzamian Maria Catarina Paz Ana Marta Paz Ndia Luísa Castanheira Maria Conceio Gonalves Fernando A. Monteiro Santos John Triantafilis 《Land Degradation u0026amp; Development》2019,30(12):1393-1406
Soil salinization limits agricultural productivity and can ultimately cause desertification and land abandonment. One approach to assess soil salinity over large areas efficiently is to use electromagnetic instruments to measure the soil apparent electrical conductivity (ECa, mS m−1). ECa data can be then inverted to generate electromagnetic conductivity images (EMCIs), which provide the vertical distribution of the soil electrical conductivity (σ, mS m−1). In this study, we collected ECa data using an EM38 instrument across four locations with different levels of salinity in an important agricultural area of alluvial origin in Portugal. Using an inversion algorithm, we generated EMCIs and evaluated the potential for prediction of the electrical conductivity of the saturated soil paste extract (ECe). The main aim of our study is to compare regional and location‐specific calibrations in terms of ability to predict ECe from EMCIs. The results showed that the regional calibration predicted ECe unbiased, precisely (root mean square error [RMSE] = 2.54 dS m−1), and with strong concordance (0.93). The location‐specific calibration also predicted ECe unbiased, precisely (RMSE = 1.67 dS m−1), and with strong concordance (0.97). We conclude that the location‐specific calibration has slightly better prediction results, but the regional calibration is more practical for mapping soil salinity in the study area because it can be used at any new location without the need for new calibration. The prediction results at locations 3 and 4 show high to severely high soil salinity, which can compromise agricultural productivity. Therefore, monitoring soil salinity is required to conserve and improve agricultural productivity in the south of the study area. 相似文献
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为研究干旱区土壤盐分空间异质性,指导农业生产实践,运用大地电导率仪（EM38、EM31）对研究区域进行移动式磁感调查,获取表观电导率（ECa）。同时,通过27个校准点的采样和ECa测量,建立土壤盐分的电磁感应解译模型。干旱区土壤盐分质量分数与EM38、EM31水平模式读数（H38、H31）显示出良好的相关性（R=0.935）,可以利用ECa结合GIS和地统计学知识研究土壤盐分的空间分布。采用两种方法进行研究：一种是先利用解译模型获取磁感调查点的土壤盐分质量分数,然后进行地统计分析研究其空间分布;另一种是先利用地统计分析研究H38和H31的空间分布,然后利用解译模型通过栅格运算计算盐分质量分数,精度检验显示前者预测值与实测值之间的相关性更好（R2, 0.888＞0.873）;标准差较低（std. 0.414＜0.426）,具有更高的预测精度。研究结果表明,基于电磁感应研究干旱区土壤盐分空间异质性是切实可行的,这对于土壤盐渍化的快速诊断,指导农业生产和促进精准农业的发展具有重要的意义。 相似文献
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Manuela S. Kaufmann Christian von Hebel Lutz Weihermüller Michael Baumecker Thomas Döring Kathlin Schweitzer Eleanor Hobley Sara L. Bauke Wulf Amelung Harry Vereecken Jan van der Kruk 《Soil Use and Management》2020,36(1):104-116
Electromagnetic induction (EMI) data are often used to investigate spatial and temporal patterns of soil texture, soil water content and soil salinity. We hypothesized that the EMI methodology might thus also offer potential to detect agricultural legacy effects originating from fertilizer application and irrigation of different fields. Therefore, we performed EMI measurements on two long-term field experiments (LTFE) at Thyrow near Berlin (Germany) that differed in agricultural management with regard to long-term irrigation in combination with mineral (NPK and lime) and organic amendments (straw and farmyard manure). Two different rigid-boom multi-coil EMI instruments were used to measure simultaneously the apparent electrical conductivity (ECa) over nine different depth ranges to study the entire soil profile from topsoil to deep subsoil. Additionally, soil samples were taken from the different treatments to ground-truth the measurements and disentangle the nutrient application or irrigation effects from natural soil heterogeneity. The soil samples indicated a rather homogenous soil and the correlation between soil parameters or states were not significant. However, the treatments showed significant differences in measured ECa values. In general, ECa values were largest on regularly irrigated as well as on mineral and organic fertilized plots, with regular irrigation exhibiting the largest impact on EMI records even though the last application was months before the EMI measurement. Overall, this study reveals that EMI data can support the classical in situ assessment of agricultural management effects within LTFE, while offering new potentials in detecting and understanding legacy effects of agricultural management on spatial soil properties at farm level. 相似文献
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针对黄河下游三角洲土壤盐渍化的空间复杂性与发生反复性,运用磁感式大地电导率仪EM38及其移动测定系统,结合GIS与地统计学方法,对该地区典型地块两个关键季节土壤盐分的时空变异特征进行了分析.结果表明,土壤表观电导率与盐分呈极显著相关性;各时段土壤盐分都表现出多层次空间结构的复合尺度效应,且短程变异构成了土壤盐分空间异质性的最主要部分;土地利用方式差异使得秋季时段土壤盐分呈弱各向异性,地形因素导致春季时段土壤盐分各向异性比在全步长域波动,但在整个研究尺度上仍为各向同性.空间分析表明,结构性因素主导了土壤盐分空间分布格局,随机性因素是加快该分布格局形成的重要因素;春季时段研究区总体表现出积盐趋势,且盐分变动幅度主要集中在10.0g/kg范围内.电磁感应仪与GIS的结合运用为不同尺度土壤调查与质量评价提供了新的途径,并为农业水土资源的决策管理提供指导. 相似文献
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土壤层次的精确划分关系到土壤学相关研究结果的精确程度。为对田间尺度上层状土壤进行无损精细分层,采用电阻率成像技术,同时结合电阻率曲线纵向上的变化特征精细划分土壤层次,并将精细分层结果应用于层状土壤电阻率空间变异性研究。结果表明:运用电阻率曲线法对反演电阻率数据进行精细划分后,形成结果图能很好的满足研究过程中可视化呈现及精细化表达等需要;根据温纳四极反演电阻率曲线法将研究区内的剖面浅层土壤划分为5—13,13—24,24—50,50—70cm 4个层次;5—13cm(耕作层)电阻率值的变异系数最高(0.28),13—24cm(犁底层)平均电阻率值最低(17.35Ω·m)。研究成果可为土壤水文学和精准农业等相关研究提供技术支撑。 相似文献
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干旱-半干旱地区不同植被条件下土壤含水量变化及植被建设途径分析 总被引：7，自引：1，他引：7
以黄土高原中北部丘陵沟壑区至风沙滩区这一特殊的过渡区域为例,对干旱-半干旱地区土壤含水量空间分异进行了分析,并对该区植被恢复途径进行了探讨.研究结果表明:(1)土壤含水量具有由北向南递增的趋势,这种趋势主要受控于降水的地带性格局,越向干旱地区,土壤含水量越不稳定;(2)不同植被类型下,草地土壤含水量较高,随土壤深度增加呈上升趋势;林地含水量较低,随深度增加呈下降趋势,且土壤干层广泛发育.草地水分的变异程度小于林地,其土壤水分较为稳定;(3)榆林样点位于古湖盆滩地的环境条件下,其土壤含水量较高,超过了半湿润地区的土壤含水量.干旱-半干旱地区进行生态恢复过程中,大面积进行植树造林是不可取的,应以草地建设为主,在某些特殊的古湖盆地质条件下,可进行部分植树造林. 相似文献
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盐碱地盐分空间分布精准识别及形成机理解析对盐碱地科学利用具有重要意义。针对传统点状采样监测方法工作量大、代表性差和检测费用高等问题,本研究采用电磁感应仪精准调查技术对上海崇明某滩涂农场进行土壤盐分空间分布评估,全面快速获得盐分空间分布信息,解析土壤盐分形成机理,进而分类分区分级指导农业生产和科学精准改良。结果表明：土壤表观电导率(ECa)和土壤盐分含量呈显著线性正相关关系(R2>0.9,P<0.05),土壤表观电导率的变化可以用来表征土壤盐分含量的变化;通过克里金插值研究区内土壤盐分的空间变异分布状况发现,研究区土壤盐分空间分布不均匀,有近80%区域存在轻中度盐碱化问题;通过定点取样土壤盐碱剖面评价,发现研究区土壤盐分具有较强的表聚性和变异强度,且变异系数随土壤深度增加不断减小;将表观电导率解译出的土壤盐分和土壤pH、有机质含量及主要组成离子含量进行相关性分析,剖析出该区域盐渍化类型以硫酸盐型为主,海水浸渍侧渗和地下水返盐影响是该区域盐渍化形成的主要原因。本研究实现了对土壤盐碱化快速、大范围、科学且动态的监测,对于全面提升盐碱地农... 相似文献
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Restoration and management of riparian areas have recently become important issues. Soil and salinity surveys are required before planning restoration activities and land‐uses if the riparian area is salt‐affected. In this study, we characterise the soils and salinity conditions of a riparian area that underwent irrigated agriculture with significant soil salinisation, to assess the general site suitability for riparian restoration and potential land‐uses. Throughout the area, 19 profiles were described and classified and 95 soil samples were collected for their chemical and physical characterisation. The salinity of the 35‐ha presumably salt‐affected area was analysed by reading the bulk soil electrical conductivity (ECa) with the hand‐held electromagnetic‐induction sensor Geonics‐EM38 at 558 locations and by measuring the electrical conductivity of the saturation extract (ECe) and sodium adsorption ratio (SAR) of 60 soil samples collected at 30 of those locations. The regression of ECe on EM readings predicted ECe with R2 > 0·92 at the 0–100 cm soil depth. The geo‐referenced soil classification (three soil units were established) and salinity maps identified the soil constraints for the area's restoration potential. The major limiting soil factors were soil salinity, sodicity and waterlogging in the southern half of the soil unit #3, and soil compaction in most of the area. The value of those limiting factors, along with differences in soil texture, as a means of assessing restoration potential of riparian vegetation and for identifying suitable land‐uses for the three soil units was discussed. Agro‐forestry, planned grazing, recreational and educational land‐uses are possible for the site. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
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G.&#x;K. Ganjegunte Z. Sheng J.&#x;A. Clark 《Land Degradation u0026amp; Development》2014,25(3):228-235
In the Far West Texas region in the USA, long‐term irrigation of fine‐textured valley soils with saline Rio Grande River water has led to soil salinity and sodicity problems. Soil salinity [measured by saturated paste electrical conductivity (ECe)] and sodicity [measured by sodium adsorption ratio (SAR)] in the irrigated areas have resulted in poor growing conditions, reduced crop yields, and declining farm profitability. Understanding the spatial distribution of ECe and SAR within the affected areas is necessary for developing management practices. Conventional methods of assessing ECe and SAR distribution at a high spatial resolution are expensive and time consuming. This study evaluated the accuracy of electromagnetic induction (EMI), which measures apparent electrical conductivity (ECa), to delineate ECe and SAR distribution in two cotton fields located in the Hudspeth and El Paso Counties of Texas, USA. Calibration equations for converting ECa into ECe and SAR were derived using the multiple linear regression (MLR) model included in the ECe Sampling Assessment and Prediction program package developed by the US Salinity Laboratory. Correlations between ECa and soil variables (clay content, ECe, SAR) were highly significant (p ≤ 0·05). This was further confirmed by significant (p ≤ 0·05) MLRs used for estimating ECe and SAR. The ECe and SAR determined by ECa closely matched the measured ECe and SAR values of the study site soils, which ranged from 0·47 to 9·87 dS m−1 and 2·27 to 27·4 mmol1/2 L−1/2, respectively. High R2 values between estimated and measured soil ECe and SAR values validated the MLR model results. Results of this study indicated that the EMI method can be used for rapid and accurate delineation of salinity and sodicity distribution within the affected area. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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为了获得新疆典型区域不同季节土壤盐分的三维特征,该研究以新疆伊犁地区典型地块为研究区域,将电磁感应式土壤表观电导率快速测定技术作为基础,建立了基于土壤表观电导率数据不同季节的区域尺度剖面分层土壤盐分精确解译模型,获得了剖面土壤盐分含量信息,并以此为数据源采用反距离权重空间数据插值方法评估了研究区不同季节三维土壤盐分空间变异特征,探索了三维土壤盐分变化对不同季节的响应特征。研究表明:研究区秋、春两个季节各土层土壤盐分含量的变异系数在1.223~1.636之间,均表现为强度变异性,秋季土壤盐分含量的变异性随着土层深度的增加而减小,而春季土壤盐分含量的变异性随着土层深度的增加而增大。秋、春两个季节研究区大部分区域土壤盐分含量比较低,土壤盐分含量高值区域主要集中在研究区的西北、西南及中部地区,并且表现出次年春季的盐渍化程度及盐土所占比例比前一年秋季明显加重。利用电磁感应式土壤表观电导率快速测定结合三维反距离权重方法,对区域不同季节土壤盐分三维空间变异特征解析的精度分别达到相关系数为0.887和0.862。研究结果将为解译与评估干旱区三维土壤盐分特征随季节变化提供可靠的理论依据和技术方法。 相似文献
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The traditional method of soil mapping involves classifying soil into pre‐existing classes using morphological observations and then air‐photograph interpretation to extrapolate the information. To accelerate the process, less costly ancillary data can be used to assist mapping. However, digital soil mapping (DSM) is still affected by the classifications used to identify soil types. One reason is because the morphological characteristics are not mutually exclusive, which causes misclassification. In this study, we used a DSM approach, where ancillary data were surrogate for morphological data, with soil types identified by numerical clustering of remotely and proximally sensed data collected across a farming district near Gunnedah, Australia. Remotely sensed data were obtained from an air‐borne gamma‐ray (γ‐ray) spectrometer survey, including potassium (K), thorium (Th), uranium (U) and total counts. Proximally sensed data were measured using EM38 (i.e. EM38h and EM38v). Using fuzzy k‐means and a linear mixed model with measured physical (e.g. clay) and chemical (e.g. CEC) properties from the topsoil (0–0.30 m) and subsoil (0.9–1.2 m), we found that k = 5 was also optimal given that mean‐squared prediction error (i.e. ) was minimised. The approach highlighted subtle differences in physical and chemical properties in productive areas. The DSM was unsuccessful in identifying small units; however, inclusion of elevation data might overcome this limitation. This research has implications for providing fast, accurate and meaningful DSM at a district scale, where traditional methods are too expensive. 相似文献
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The electromagnetic induction (EMI) Geonics EM38 (G‐EM38) and Dualem 1S (D‐1S) sensors are used frequently for assessment of soil salinity and other soil characteristics in irrigated agriculture. We compared these two sensors to determine whether they could be used interchangeably for the measurement of apparent soil electrical conductivity (ECa) in horizontal (ECa‐h) and vertical (ECa‐v) coil receiver modes. Readings were taken at 201 locations identified in three irrigation districts in both modes, and statistical comparisons were made on the raw data and from maps of a 2‐ha irrigated field made using 1680 horizontal mode readings. Both sensors gave the same ECa‐v readings (mean G‐EM38 and D‐1S difference = 0), whereas the ECa‐h readings were slightly greater with the Geonics EM38 than with the Dualem D‐1S (mean difference = 0.075 and 0.05 dS/m for the 201 and 1680 observations, respectively). The degree of coincidence between both sensors for soil profile ECa classification was acceptable: 82% for normal profiles (i.e. ECa‐h/ECa‐v < 0.9) and 90% for inverted profiles (i.e. ECa‐h/ECa‐v > 1.1). In practical terms, Geonics EM38 and Dualem 1S sensors could be used interchangeably with similar or very close results. 相似文献
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U. W. A. Vitharana M. Van Meirvenne L. Cockx & J. Bourgeois 《Soil Use and Management》2006,22(4):405-413
Variation in soil texture has a profound effect on soil management, especially in texturally complex soils such as the polder soils of Belgium. The conventional point sampling approach requires high sampling intensity to take into account such spatial variation. In this study we investigated the use of two ancillary variables for the detailed mapping of soil texture and subsequent delineation of potential management zones for site‐specific management. In an 11.5 ha arable field in the polder area, the apparent electrical conductivity (ECa) was measured with an EM38DD electromagnetic induction instrument. The geometric mean values of the ECa measured in both vertical and horizontal orientations strongly correlated with the more heterogeneous subsoil clay content (r = 0.83), but the correlation was weaker with the homogenous topsoil clay content (r = 0.40). The gravimetric water content at wilting point (θg(?1.5 MPa)) correlated very well (r = 0.96) with the topsoil clay content. Thus maps of topsoil and subsoil clay contents were obtained from 63 clay analyses supplemented with 117θg(?1.5 MPa) and 4048ECa measurements, respectively, using standardized ordinary cokriging. Three potential management zones were identified based on the spatial variation of both top and subsoil clay contents. The influence of subsoil textural variation on crop behaviour was illustrated by an aerial image, confirming the reliability of the results from the small number of primary samples. 相似文献
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Jessica Schmäck Lutz Weihermüller Anja Klotzsche Christian von Hebel Stefan Pätzold Gerhard Welp Harry Vereecken 《Soil Use and Management》2022,38(1):212-228
Fast and accurate large-scale localization and quantification of harmfully compacted soils in recultivated post-mining landscapes are of particular importance for mining companies and the following farmers. The use of heavy machinery during recultivation imposes soil stress and can cause irreversible subsoil compaction limiting crop growth in the long term. To overcome or guide classical point-scale methods to determine compaction, fast methods covering large areas are required. In our study, a recultivated field of the Garzweiler mine in North Rhine-Westphalia, Germany, with known variability in crop performance was intensively studied using non-invasive electromagnetic induction (EMI) and electrode-based electrical resistivity tomography (ERT). Additionally, soil bulk density, volumetric soil water content and soil textures were analysed along two transects covering different compaction levels. The results showed that the measured EMI apparent electrical conductivity (ECa) along the transects was highly correlated (R2 > .7 for different dates and depths below 0.3 m) to subsoil bulk density. Finally, the correlations established along the transects were used to predict harmful subsoil compaction within the field, whereby a spatial probabilistic map of zones of harmful compaction was developed. In general, the results revealed the feasibility of using the EMI derived ECa to predict harmful compaction. They can be the basis for quick monitoring of the recultivation process and implementation of necessary melioration to return a well-structured soil with good water and nutrient accessibility, and rooting depths for increased crop yields to the farmers. 相似文献
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莫索湾灌区土壤剖面盐分的季节性变化特征 总被引：1，自引：0，他引：1
以新疆莫索湾灌区为研究区域,通过对该地区春季和秋季土壤剖面取样,得到土壤盐分值并采用Arc-gis 10.0软件对土壤盐分进行地统计学分析,从而探索莫索湾灌区不同季节土壤剖面盐分的空间变化特征。结果表明：研究区土壤剖面盐分含量随土层深度的增加而升高,属于底聚型;盐分含量总体表现为东南部高于西北部,2014春季高于2013年秋季,是因为灌区春季温度高于秋季,且积雪融化造成部分地区地下水位升高,强烈的地表蒸发使得底层盐分上移到耕层。不同季节各层土壤盐分含量值都符合对数正态分布,变异系数在66％~92％之间,具有中等强度的空间变异性,表层土壤变异大于底层;半方差分析得出2013年秋季和2014年春季各土层土壤盐分含量可以用高斯模型、指数模型和线性模型拟合,拟合模型的R2均大于0.75;土壤盐分含量的块金系数 C0/( C0＋ C )值在31％~42％之间,盐分含量值均表现为中等强度的空间自相关,0~100 cm土壤盐分受自然因素和人为因素共同作用。研究结果可为莫索湾灌区盐渍化土壤的分区、改良和利用提供理论基础。 相似文献
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[目的]研究不同种植年限压砂地及裸地不同土层土壤盐分的空间变异特征,为西北干旱地区土壤盐渍化改良和利用提供理论依据。[方法]以甘肃省景泰县压砂地及裸地不同土层土壤盐分数据为基础,运用经典统计学和地统计学相结合的方法,分析土壤盐分统计特征值,半方差模拟模型及其拟合参数和等值线分布图。[结果]压砂地土壤盐分均值明显低于裸地,且裸地老砂地新砂地中砂地,裸地与压砂地各层土壤盐分的均值差异较大,且土层Ⅳ(30—50cm)土层Ⅲ(20—30cm)土层Ⅱ(10—20cm)土层Ⅰ(0—10cm);裸地Ⅱ,Ⅲ,Ⅳ层,中砂地各层土壤盐分属于弱变异性,其他各地型各土层土壤盐分都属于中等变异性。裸地Ⅰ,Ⅲ层,新砂地第Ⅲ层,中砂地第Ⅰ层,老砂地Ⅰ,Ⅱ,Ⅲ层土壤盐分半方差函数最佳理论模型为指数模型,裸地第Ⅱ层为线性模型,其他各地型各土层均为球状模型。裸地第Ⅱ层土壤盐分具有弱空间相关性,其余各土层土壤盐分均具有强相关性。试验区土壤盐分北部高于南部,且各土层土壤盐分在一定范围内存在空间上的变异性和相关性。[结论]土壤表层压砂能有效减小土壤盐分表聚,抑制土壤次生盐渍化,不同种植年限压砂地不同土层土壤盐分在一定范围内存在空间上的变异性和相关性。 相似文献
