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1.
Soil sodicity is an increasing problem in arid‐land irrigated soils that decreases soil permeability and crop production and increases soil erosion. The first step towards the control of sodic soils is the accurate diagnosis of the severity and spatial extent of the problem. Rapid identification and large‐scale mapping of sodium‐affected land will help to improve sodicity management. We evaluated the effectiveness of electromagnetic induction (EM) measurements in identifying, characterizing and mapping the spatial variability of sodicity in five saline‐sodic agricultural fields in Navarre (Spain). Each field was sampled at three 30‐cm soil depth increments at 10–30 sites for a total of 267 soil samples. The number of Geonics‐EM38 measurements in each field varied between 161 and 558, for a total of 1258 ECa (apparent electrical conductivity) readings. Multiple linear regression models established for each field predicted the average profile ECe (electrical conductivity of the saturation extract) and SAR (sodium adsorption ratio of the saturation extract) from ECa. Despite the lack of a direct causal relationship between ECa and SAR, EM measurements can be satisfactorily used for characterizing the spatial distribution of soil sodicity if ECe and SAR are significantly auto‐correlated. These results provide ancillary support for using EM measurements to indirectly characterize the spatial distribution of saline‐sodic soils. More research is needed to elucidate the usefulness of EM measurements in identifying soil sodicity in a wider range of salt and/or sodium‐affected soils.  相似文献   

2.
Large areas of Morocco require irrigation and although good quality water is available in dams, farmers augment river water with poorer quality ground water, resulting in salt build‐up without a sufficient leaching fraction. Implementation of management plans requires baseline reconnaissance maps of salinity. We developed a method to map the distribution of salinity profiles by establishing a linear regression (LR) between calculated true electrical conductivity (σ, mS/m) and electrical conductivity of the saturated soil‐paste extract (ECe, dS/m). Estimates of σ were obtained by inverting the apparent electrical conductivity (ECa, mS/m) collected from a 500‐m grid survey using an EM38. Spherical variograms were developed to interpolate ECa data onto a 100 m grid using residual maximum likelihood. Inversion was carried out on kriged ECa data using a quasi‐3d model (EM4Soil software), selecting the cumulative function (CF) forward modelling and S2 inversion algorithm with a damping factor of 3.0. Using a ‘leave‐one‐out cross‐validation' (LOOCV), of one in 12 of the calibration sites, the use of the q‐3d model yielded a high accuracy (RMSE = 0.42 dS/m), small bias (ME = ?0.02 dS/m) and Lin's concordance (0.91). Slightly worse results were obtained using individual LR established at each depth increment overall (i.e. RMSE = 0.45 dS/m; ME = 0.00 dS/m; Lin's = 0.89) with the raw EM38 ECa. Inversion required a single LR (ECe = 0.679 + 0.041 × σ), enabling efficiencies in estimating ECe at any depth across the irrigation district. Final maps of ECe, along with information on water used for irrigation (ECw) and the characterization of properties of the two main soil types, enabled better understanding of causes of secondary soil salinity. The approach can be applied to problematic saline areas with saline water tables.  相似文献   

3.
基于多源数据的中原黄泛区土壤盐分空间变异分析   总被引：6，自引：4，他引：6  
为研究中原黄泛区土壤盐分空间变异,以河南省封丘县为研究区,综合考虑引起土壤盐渍化的土壤盐分、地形、地下水位及矿化度、植被情况及其他影响因素,基于遥感影像和磁感式探测获得的土壤表观电导率等多源数据建立了区域土壤盐分综合评估模型,并对研究区分层土壤盐分空间变异进行评估。结果表明:对于0~60 cm土层利用多源数据进行模型构建中土壤表观电导率与光谱指数占主要比例,模型对于各层土壤盐分的评价精度0~60 cm土层优于≥60~120 cm土层。土壤盐分含量随着深度的增加而增大,变异系数在0.22~0.28之间,属中等变异强度。土壤盐分主要集中分布在研究区北部与东南部,尤其是东南角黄河沿线区域,且随着土壤剖面显示出从表现到深层逐渐增加的趋势。利用多源数据建立的分层土壤盐分综合评估模型对于区域土壤盐分解析具有较高精度。该研究为中原黄泛区土壤盐化消减与土壤质量提升提供了可靠新方法。  相似文献   

4.
采用新电导率指标分析土壤盐分变化规律   总被引：9，自引：0，他引：9  
土壤电导率(Electrical conductivity,EC)是限制植物和微生物活性的阈值,影响到土壤养分和污染物的转化、存在状态及有效性[1],反映了在一定水分条件下土壤盐分的实际状况,且包含了土壤水分含量及离子组成等丰富信息[2]。在一定浓度范围内,土壤溶液含盐量与电导率呈正相关,溶解的盐类越多,溶液电导率就越大,故可根据溶液电导率的大小,间接地测量土壤含盐量[3-5]。  相似文献   

5.
In the oldest commercial wine district of Australia, the Hunter Valley, there is the threat of soil salinization because marine sediments underlie the area. To understand the risk requires information about the spatial distribution of soil properties. Electromagnetic (EM) induction instruments have been used to identify and map the spatial variation of average soil salinity to a certain depth. However, soils vary with depth dependent on soil forming factors. We collected data from a single‐frequency and multiple‐coil DUALEM‐421 along a toposequence. We inverted this data using EM4Soil software and evaluated the resultant 2‐dimensional model of true electrical conductivity (σ – mS/m) with depth against electrical conductivity of saturated soil pastes (ECp – dS/m). Using a fitted linear regression (LR) model calibration approach and by varying the forward model (cumulative function‐CF and full solution‐FS), inversion algorithm (S1 and S2), damping factor (λ) and number of arrays, we determined a suitable electromagnetic conductivity image (EMCI), which was optimal (R2 = 0.82) when using the full solution, S2, λ = 3.6 and all six coil arrays. We conducted an uncertainty analysis of the LR model used to estimate the electrical conductivity of the saturated soil‐paste extract (ECe – dS/m). Our interpretation based on estimates of ECe suggests the approach can identify differences in salinity, how these vary with parent material and how topography influences salt distribution. The results provide information leading to insights into how soil forming factors and agricultural practices influence salinity down a toposequence and how this can guide soil management practices.  相似文献   

6.
In coastal China, there is an urgent need to increase land for agriculture. One solution is land reclamation from coastal tidelands, but soil salinization poses a problem. Thus, there is need to map saline areas and identify appropriate management strategies. One approach is the use of digital soil mapping. At the first stage, auxiliary data such as remotely sensed multispectral imagery can be used to identify areas of low agricultural productivity due to salinity. Similarly, proximal sensing instruments can provide data on the distribution of soil salinity. In this study, we first used multispectral QuickBird imagery (Bands 1–4) to provide information about crop growth and then EM38 data to indicate relative salt content using measurements of apparent soil electrical conductivity (ECa) in the horizontal (ECh) and vertical (ECv) modes of operation. Second, we used a fuzzy k‐means (FKM) algorithm to identify three salinity management zones using the normalized difference vegetation index (NDVI), ECh and ECv/ECh. The three identified classes were statistically different in terms of auxiliary and topsoil properties (e.g. soil organic matter) and more importantly in terms of the distribution of soil salinity (ECe) with depth. The resultant three classes were mapped to demonstrate that remote and proximally sensed auxiliary data can be used as surrogates for identifying soil salinity management zones.  相似文献   

7.
To understand the limitations of saline soil and determine best management practices, simple methods need to be developed to determine the salinity distribution in a soil profile and map this variation across the landscape. Using a field study in southwestern Australia, we describe a method to map this distribution in three dimensions using a DUALEM‐1 instrument and the EM4Soil inversion software. We identified suitable parameters to invert the apparent electrical conductivity (ECa – mS/m) data acquired with a DUALEM‐1, by comparing the estimates of true electrical conductivity (σ – mS/m) derived from electromagnetic conductivity images (EMCI) to values of soil electrical conductivity of a soil‐paste extract (ECe) which exhibited large ranges at 0–0.25 (32.4 dS/m), 0.25–0.50 (18.6 dS/m) and 0.50–0.75 m (17.6 dS/m). We developed EMCI using EM4Soil and the quasi‐3d (q‐3d), cumulative function (CF) forward modelling and S2 inversion algorithm with a damping factor (λ) of 0.07. Using a cross‐validation approach, where we removed one in 15 of the calibration locations and predicted ECe, the prediction was shown to have high accuracy (RMSE = 2.24 dS/m), small bias (ME = ?0.03 dS/m) and large Lin's concordance (0.94). The results were similar to those from linear regression models between ECa and ECe for each depth of interest but were slightly less accurate (2.26 dS/m). We conclude that the q‐3d inversion was more efficient and allowed for estimates of ECe to be made at any depth. The method can be applied elsewhere to map soil salinity in three dimensions.  相似文献   

8.
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   

9.
We hypothesised that digital mapping of various forms of salt‐affected soils using high resolution satellite imagery, supported by field studies, would be an efficient method to classify and map salinity, sodicity or both at paddock level, particularly in areas where salt‐affected patches are small and the effort to map these by field‐based soil survey methods alone would be inordinately time consuming. To test this hypothesis, QuickBird satellite data (pan‐sharpened four band multispectral imagery) was used to map various forms of surface‐expressed salinity in an agricultural area of South Australia. Ground‐truthing was performed by collecting 160 soil samples over the study area of 159 km2. Unsupervised classification of the imagery covering the study area allowed differentiation of severity levels of salt‐affected soils, but these levels did not match those based on measured electrical conductivity (EC) and sodium adsorption ratio (SAR) of the soil samples, primarily because the expression of salinity was strongly influenced by paddock‐level variations in crop type, growth and prior land management. Segmentation of the whole image into 450 paddocks and unsupervised classification using a paddock‐by‐paddock approach resulted in a more accurate discrimination of salinity and sodicity levels that was correlated with EC and SAR. Image‐based classes discriminating severity levels of salt‐affected soils were significantly related with EC but not with SAR. Of the spectral bands, bands 2 (green, 520–600 nm) and 4 (near‐infrared, 760–900 nm) explained the majority of the variation (99 per cent) in the spectral values. Thus, paddock‐by‐paddock classification of QuickBird imagery has the potential to accurately delineate salinity at farm level, which will allow more informed decisions about sustainable agricultural management of soils. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

10.
Since 1954, the electrical conductivity of the saturated paste extract (ECe) has been the preferred index for soil salinity. Based on this value, remediation strategies were developed and widely used but this approach is time consuming and not routinely offered by many soil testing facilities. However, many laboratories determine the EC1:1 value of a 1:1 soil to solution ratio extract. The objective of this study was to identify the relationship between ECe and EC1:1 and determine if EC1:1 can be used as a proxy in the northern Great Plains for ECe. Samples were collected across five studies and from AGVISE Laboratory. The samples were analyzed for EC1:1 and ECe. The relationship between the ECe and EC1:1 showed that soil parent materials need to be considered in the conversion of EC1:1 values to ECe values. A failure to consider parent materials in this conversion may have short and long-term sustainability ramifications.  相似文献   

11.
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   

12.
Salinisation of land resources is a major impediment to their optimal utilisation in many arid and semi‐arid regions of the world including Iran. Estimates suggest that about 34 million ha, including 4·1 million ha of the irrigated land, are salt‐affected in Iran as the consequence of naturally occurring phenomena and anthropogenic activities. The annual economic losses due to salinisation in the country are more than US$ 1 billion. With variable levels of success, different approaches—salt leaching and drainage interventions, crop‐based management, chemical amendments and fertilisers and integrated application of these approaches—have been used to enhance the productivity of salt‐affected soils in the Country. From sustainable management perspective, it is revealed from the past research that integrated salinity management and mitigation approaches have the potential to successfully address the complex problems of salt‐induced land degradation in Iran. As the growing need to produce more food and fibre for the expanding Iranian population necessitates the increased use of salt‐affected land resources in the foreseeable future, there is an urgent need to develop and implement a pertinent National Strategic Plan. In addition to establishing networks for monitoring spatial and temporal changes in soil salinity and water quality, this plan should integrate the management of salt‐affected environments into the overall management of land and water resources in the country. It should also address different management aspects of salt‐affected land resources in a holistic manner by considering the biophysical and environmental conditions of the target areas as well as livelihoods of the affected communities. The involvement of the communities will facilitate in developing a greater understanding about the potential uses and markets of the agricultural products produced from salt‐affected areas. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

13.
基于EM38长江河口地区土壤盐渍化特征研究   总被引：2，自引：0，他引：2  
运用电磁感应仪EM38,结合GIS技术和地统计方法对长江河口地区土壤含盐量的空间变异性进行研究,结果表明:EM38所测土壤表观电导率与土壤电导率(EG_(1:5))的相关系数均达到1%显著水平,其中以EM_h+EM_v为自变量的多元回归方程的拟合效果最好.盐分含量统计特征表明,土壤盐分含量变幅较大,且随着深度的增加变化幅度逐渐减小,各层土壤盐分含量均值介于0.713 6～0.813 7 g/kg之间,且随着深度的增加盐分含量均值逐渐增大,总体上盐分分布具有一定的底聚性;各土层含盐量均呈现中等变异强度.变异系数相差较大,在水平方向上含盐量的变异随深度的增加而逐步趋弱.盐分含量空间分布表明,各层土壤盐分含量由南向北、自东向西有逐渐降低的趋势,随着深度的增加土壤含盐量不断升高.盐化土面积百分比表明,该地区大部分为非盐化土,轻度盐化土和中度盐化土所占比例较小,但由于含盐母质和地下水矿化度两个主要因素的影响,土壤盐渍化的发生存在巨大的潜在性威胁,运用EM38测值解译所得土壤盐分含量真实地反映了研究区的土壤盐渍化状况,为该地区土壤盐渍化的改良及防范提供依据.  相似文献   

14.
基于电磁感应的典型干旱区土壤盐分空间异质性   总被引：5，自引：1，他引：4  
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   

15.
In order to utilize the wasted saline-sodic soils under shallow groundwater condition,a 3-year field study was carried in a field cropped with Lycium barbarum L.and irrigated by drip irrigation with saline groundwater under the water table depth of 30-40 cm in the northern Yinchuan Plain,China.Effects of cropping duration (one,two,and three years) on soil salinity,soil solution composition,and pH in three adjacent plots were investigated in 2008.Results showed that a high irrigation frequency maintained high soil water potential and subsequently facilitated infiltration and downward movement of water and salt in the crop root zone.Salt accumulated on the edges of the ridges,and soil saturated-paste electrical conductivity (ECe) was higher in the edge.Concentrations of Na+,Ca2+,Mg2+,Cl-,and SO42- in the soil increased with the soil depth as did the ECe,while HCO3- and pH had a relative uniform distribution in soil profile.As planting year increased,the ECe and soil salts in the field had a decreasing tendency,while in the root zone they decreased immediately after irrigation and then remained relatively stable in the following growing seasons.HCO3- and pH had little change with the planting year.Results suggested that the application of drip irrigation with saline water could ameliorate saline-sodic soil and provide a relatively feasible soil environment for the growth of salt-tolerant plant Lycium barbarum L.under the saline-sodic soils with shallow groundwater.  相似文献   

16.
用SahysMod模型研究不同灌排管理情景土壤水盐动态   总被引：1，自引：1，他引：0  
银北灌区是宁夏土地整治和高标准灌溉绿洲农田建设的重点区域。该区域耕荒地交错分布、土壤盐渍化严重。通过模型分区模拟,在土地整治过程中建立完整、配套的灌排系统是解决区域土壤盐渍化的有效措施。该研究以银北灌区典型区域-西大滩为例,综合考虑荒地与耕地土壤属性的空间变异性,以2015—2016年土壤盐分数据进行率定,2017年盐分数据作为验证,利用SahysMod探索在土地整治过程中不同灌排管理下未来10 a内土壤水盐动态变化。结果表明,现有灌排管理下(即灌水量为670 mm,灌溉水电导率为1.05 dS/m,排水沟深1.5 m),荒地土壤盐分在预测初期(2017—2022年)逐年升高,预测后期(2023—2027年)变化平缓;耕地土壤盐分在预测初期变化缓慢,预测后期逐年增加。加大灌水量是解决土壤盐渍化的一个重要途径,可以有效延迟耕地盐分累积到障碍水平的时间;在灌溉水电导率为0.6 dS/m情况下,未来10 a内耕地都不会受到盐害胁迫;现有灌排管理下,在2024年以后作物生长就会受到盐害胁迫,当灌溉水电导率继续增加时,作物生长受到胁迫的时间相应提前。通过土地整治,加深排水沟深度可以延迟土壤盐分达到障碍水平的时间。在整治过程中深为2.2 m的排水沟,可保证未来10 a内耕地盐分小于1.7 dS/m,区域内玉米可正常生长。研究可为在土地整治过程中的灌排管理及土壤盐渍化防治提供建议。  相似文献   

17.
不同措施对滨海盐渍土壤呼吸、电导率和有机碳的影响   总被引：2，自引：0，他引：2  
在苏北滩涂围垦区的轻度和中度盐渍土上,通过田间试验,研究了不同农田管理措施(传统耕作、施用有机肥、氮肥增施、秸秆还田和免耕)对土壤盐分、呼吸和有机碳等的影响。结果表明,0~40cm土层平均电导率在玉米种植季明显升高,小麦种植季出现小幅降低,轻度盐渍土的电导率为4.57~8.20 d S m~(~(-1)) ,中度盐渍土为4.89~10.13 d S m~(~(-1)) ,处理之间秸秆还田最低,免耕最高,秸秆还田和施用有机肥有效减少了土壤盐分含量。与中度盐渍土相比,轻度盐渍土的呼吸强度较高,在夏玉米和冬小麦种植季节分别高约16%和18%。有机肥、氮肥增施、秸秆还田处理的土壤呼吸均高于对照,而免耕较低。两组试验的土壤有机碳和微生物生物量碳均有缓慢增加,其中施用有机肥和秸秆还田可以大幅提高其含量。轻度盐渍土壤代谢熵高于中度盐渍土,总体上对照最高,免耕最低。  相似文献   

18.
基于磁感式探测的分层土壤盐分精确解译模型   总被引：2，自引：1，他引：1  
为了精准解译面域尺度土壤盐分特征,有必要建立分层土壤盐分信息精确解译模型。该文应用通径分析方法,研究获得了土壤全盐量、土壤含水率、体积质量、黏粒质量分数、地下水电导率、地下水埋深等作用因子对土壤表观电导率值的方差贡献率及作用强弱排序。依据各作用因子的方差贡献率大小,结合设定的累积贡献率阀值,选取出磁感式土壤表观电导率的主导作用因子,确定为磁感式土壤盐分信息解译模型的参数体系。采用多因子及互作项逐步回归法,通过引入因子间的互作效应建立优化的基于磁感式探测的分层（0～20,＞20～60,＞60～100,＞100～160 cm）土壤盐分信息解译模型。验证结果表明,模型解译误差基本在10%以内,达到了较高精度水平。  相似文献   

19.
Abstract

To better understand the adverse impacts of soil salinization and promote rice (Oryza sativa L.) production in crops from the north central coastal region of Vietnam, the spatiotemporal variability of soil salinity and its effects on rice production were investigated. Experiments were conducted at 19 plots widely distributed in the Quang Phuoc commune, in the Quang Dien district of the province of Thua Thien Hue in the north central coastal region of Vietnam. We determined the elevation of the 19 plots to evaluate the influence of elevation on salt accumulation. Soil samples from the 19 plots were collected in January, May and September 2012 and 2013 to study the spatiotemporal variability of salinity. A soil saturation paste was prepared and used to measure electrical conductivity (ECe). The elevation measurements obtained suggest that the research site could be divided into low- and high-elevation plots, with elevation of the low-elevation plots ranging from –0.52 to 0.07 m and the high-elevation plots from 0.26 to 0.86 m (one of the sampling plot was designated with an elevation of 0 m and the elevations of the remaining 18 plots were measured relative to that). ECe was high at low elevations. In conclusion, although the differences in elevation between the 19 plots were very small (centimeters to decimeters), they still led to large differences in soil salinity levels. In the high-elevation plots, soils were irrigated with freshwater, thus maintaining low ECe levels throughout the year (< 1.0 dS m?1). In contrast, in the low-elevation plots, soils were subject to seawater intrusion, resulting in high ECe levels in all seasons (> 1.9 dS m?1). We recommend several solutions to limit the unfavorable effects of salinity and promote rice production. First, a comprehensive dike system should be constructed along the lagoon to prevent seawater intrusion onto land. Second, it will be necessary to construct adequate drainage facilities in the depressed areas to promote rapid water drainage into canals during and after flooding and irrigation. Third, because ECe was high from May to September, adequate fresh irrigation water should be frequently supplied to lower the ECe during this period.  相似文献   

20.
土壤盐分的原位测定方法   总被引：10，自引：1，他引：9  
刘梅先  杨劲松 《土壤》2011,43(5):688-697
在干旱半干旱地区,土壤盐溃化是制约农业生产的重要因素.土壤盐分的测定和诊断是土壤盐渍化研究工作中的重要内容,传统上一般通过测定土壤浸提液电导率来测定土壤盐分,过程繁琐,费时费事,不可避免地要破坏原土样.在提倡精准农业的今天,土壤盐分的快速、有效和可靠的原位测定显得非常重要.土壤盐分原位测量方法有多种,在原理上可分为土壤...  相似文献   

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