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1.
基于电磁感应技术的区域三维土壤盐分空间变异研究 总被引：3，自引：0，他引：3
以孔雀河流域典型地带为研究区域,利用电磁感应式大地电导率快速测定技术探测获得表观土壤电导率数据,构建了基于电磁感应技术的区域尺度剖面分层土壤盐分精确解译模型,精准解译出研究区剖面土壤盐分含量信息,并以此为数据源采用三维普通克里格法解析并评估了研究区土壤盐分三维空间分布特征。研究表明,不同测量位数据的综合应用能够表征剖面土壤盐分信息,构建出的剖面分层土壤盐分解译模型具有较好的精度;研究区不同区位土壤盐分三维分布呈现明显差异;研究区土壤主体属中度以上盐渍化,局部地带属于重度以上盐渍化土壤,需采取有效治理措施对土壤盐渍化进行可靠防控。 相似文献
2.
该文采用EM38电磁感应电导率仪测量辽宁省阜新市海州露天矿场复垦区一块面积为5 000 m2的覆土层的表观电导率,试探性研究表观电导率（ECa）与矿区排土场覆土厚度（TSLT）的相关性。测定结果证实ECa与相同点位剖面挖掘所得的深度数据有很好的负相关性,而两层土壤的电导率差值与上层土壤深度之间存在一定的正相关性。结合地统计克里格插值,得到了该复垦区覆土深度分布的预测趋势图。研究结论指出,基于EM38测量的表观电导率预测矿区复垦区覆土层厚度具有良好的可行性,为废弃矿区复垦质量的客观评估,提供了一种实用、简捷的工程检测 手段。 相似文献
3.
对沈阳地区高粱不同保墒措施下土壤剖面养分状况(包括碱解氮、速效钾、有机质和电导率)进行测定研究,结果表明:不同保墒措施下,土壤剖面碱解氮含量均随土层深度增加呈减少趋势,其中黑膜覆盖增加最大,白膜覆盖次之,秸秆覆盖、施用保水剂依次;土壤剖面速效钾含量均随土层深度增加呈减少趋势,覆膜处理和保水剂处理具有明显的增钾效果,秸秆覆盖増钾作用不甚显著;秸秆覆盖能明显地增加耕层有机质含量,白膜覆盖和黑膜覆盖次之,施用保水剂土壤剖面有机质含量变化不显著;各保墒处理对土壤表层盐分的累积有明显的抑制作用,其中秸秆覆盖抑制效果最明显,黑色地膜、白膜覆盖和保水剂依次. 相似文献
4.
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
5.
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
6.
以塔里木河下游35团8连绿洲-荒漠交界处滴灌条件下的新生林地为研究对象,对滴灌结束24 h后不同滴头间距下的土壤盐分分布特征进行了分析,结果显示①水平方向上,在3 m滴头间距下出现盐峰是在75 cm点处的土壤剖面,这一剖面与60 cm点处的土壤剖面盐分在0.01水平上呈显著相关,随着距滴头距离的减小相关性递减;在1 m滴头间距下出现盐峰是在45 cm点处的土层,这一土层与各点处的土壤剖面盐分在0.01水平上呈显著相关;无论在3 m滴头间距下还是在1 m滴头间距下,45 cm点处的土壤剖面盐分分布较均匀,离滴头越近的土壤剖面盐分分布越不均匀。②垂直方向上,无论是在3 m滴头间距下还是在1 m滴头间距下,40~60 cm的土层是盐分聚集区。在3 m滴头间距下,40~60 cm的土层盐分与各土层间的相关系数均未达显著相关水平;在1 m滴头间距下,40~60 cm的土层盐分与其它各土层间均为负相关关系;无论是在3 m滴头间距下还是在1 m滴头间距下,中下层土壤盐分分布较均匀,而越接近表层的土壤盐分分布越不均匀,在2种滴头间距下,中下层土壤盐分变异系数都较小,表层土壤变异系数较大。③在研究区特殊的强蒸发力下,原本可到达底部土层的盐分在毛管作用下随着水分向上运动,最终导致了盐分聚集于50 cm深度处(3 m滴头间距)与65 cm深度处(1 m滴头间距)。 相似文献
7.
利用电容式传感器连续监测土壤硝态氮质量分数的试验研究 总被引：1，自引：0，他引：1
通过室内和田间试验,研究土壤硝态氮质量分数与电容式传感器监测的土壤电导率、含水率和温度的定量关系。在室内以NH4NO3分析纯为溶质,进行了溶液质量浓度0～10g/L的7次土柱试验;在2009年和2010年春玉米生育期内监测了不同滴灌水量条件下土壤电导率、含水率和温度动态变化。结果表明,土壤电导率能较好的反映土壤硝态氮质量分数的变化;土壤硝态氮质量分数与电导率、含水率和温度之间的关系可用二次多项式描述,且3个土壤参数对土壤硝态氮质量分数的影响均达到了极显著水平(P≤0.01);由于回归模型的拟合精度受土壤初始养分盐分质量分数及空间变异等因素的影响,为获得较高的预测精度,应进行田间标定。 相似文献
8.
2005年4~7月期间利用W.E.T电导率测量仪,采用网格化取样方式对烟台农科院梨园的表层土壤(0~30cm)电导率的162个样点进行了3次取样,并对土壤电导率适宜样本容量的影响因素进行了研究。结果表明,在所考虑的置信水平和精度范围内,相对于取样间距的变化,不同取样时间土壤电导率合理采样数的变化更加明显,取样间距不同引起的合理采样数的变化幅度介于1.28%~11.36%之间,取样时间不同时合理采样数的变化幅度介于33.33%~45.67%之间。因此在研究区域内,由人为因素(施肥等)引起的土壤电导率分布状况是影响其合理取样数目的主要因素。 相似文献
9.
次生盐渍土垂向剖面斥水性及其与理化性质关系 总被引：1，自引：0，他引：1
为探求土壤剖面斥水性的变化规律及其与土壤水盐含量、pH值的关系,在新疆新垦膜下滴灌棉田以10 cm×10 cm和5cm×5cm的网格等间距采集两个土壤剖面样品,对剖面土壤的斥水性、含水率、含盐量和pH值了进行经典统计、地学统计和相关性分析。结果表明：次生盐渍土剖面斥水性呈中等程度变异,空间自相关性中等偏弱;土壤斥水性在40cm深度附近时最强,在大于80cm深度的土层斥水特征不明显;在0~40cm深度土层,含水率与土壤斥水性正相关,在40~80cm深度与斥水性负相关;含盐量除在0~10cm的表层与斥水性正相关外,在其余土层均为负相关; pH值与斥水性之间多为正相关。 相似文献
10.
【目的】土壤盐渍化是限制新疆南部棉花高产的主要因子,准确获取区域尺度土壤剖面盐分信息。【方法】以南疆阿拉尔垦区为研究区,以田间尺度采集的30个不同盐渍化程度棉田的540个样点的0~0.375、0~0.750、0~1.000 m的土壤剖面电导率数据和对应的电磁感应数据为数据源,采用线性模型和非线性模型分别构建了田间尺度和区域尺度的土壤剖面电导率的电磁感应反演模型,并采用缩减建模样本量方法进一步检验了区域尺度模型的可靠性和稳定性。【结果】多元线性回归(MLR)、偏最小二乘回归(PLSR)和主成分回归(PCR)建模方法的田间尺度模型R2在0.88~0.95,而对应的区域尺度模型R2在0.34~0.53。基于随机森林(RF)、神经网络(NN)和支持向量机(SVM)非线性建模方法构建的土壤剖面电导率的区域尺度电磁感应反演模型R2在0.60~0.85,其中RF模型的精度最高。0~0.375、0~0.750、0~1.000 m土壤剖面电导率的RF反演模型R2分别为0.80、0.85和0.84,相较于线性建模方法的区域尺度模型精度有明显的提高。RF区域尺度模型的样本数量由540个缩减到240个,模型精度没有明显变化,表明采用区域尺度模型,可大幅度降低土壤剖面样本采集数量,从而可显著提高采样效率和降低采样成本。【结论】区域尺度下构建土壤剖面电导率反演模型时,随机森林建模方法效果较优,模型预测能力具有较高的可靠性。 相似文献
11.
矿区农田土壤重金属分布特征与污染风险研究 总被引：4，自引：0，他引：4
对渭北旱原矿区130个农田土壤样品的Cd、Cr、Cu、Pb、Zn含量进行了测定,结果显示,Cd、Cu、Pb平均含量均高于陕西省土壤背景值,而Cr和Zn含量低于背景值。利用地统计方法得到的土壤重金属含量分布图显示,土壤各重金属含量由西向东呈下降趋势,水泥厂周边土壤重金属含量最高。相关性分析和主成分分析结果表明,5种重金属之间呈极显著正相关,说明其存在较高的同源性或复合关系。第1主成分主要由Cd构成,且主要反映了人为活动的影响,而第2主成分中的Cr所占负荷最高,体现了成土母质的作用,Cu、Pb和Zn含量受人为活动和成土母质共同影响。分别利用污染负荷指数(PLI)法和潜在生态危害指数(PER)法对研究区域土壤污染风险进行了评价,评价结果为煤矿区呈无污染或轻微到中度污染,水泥厂区土壤呈中度污染水平,单一元素污染程度由高到低依次为Cd、Pb、Cu、Cr、Zn。 相似文献
12.
利用土壤含水率与近红外光谱土壤反射率和土壤电导率三者之间的关系,以土壤含水率为中间变量,间接表达土壤光谱反射率和土壤电导率之间的关系。土壤含水率与土壤光谱反射率存在指数关系,土壤含水率与土壤电导率存在线性关系,消除中间变量（土壤含水率）,得到土壤光谱反射率和土壤电导率之间的关系。以土壤水分敏感波段1450nm作为研究对象,研究土壤电导率的预测模型,分别建立指数预测模型和对数预测模型,并分别对两种模型进行验证。本文实验建模集样本72个,验证集样本48个,土壤电导率对数预测模型R2达0.80,土壤电导率指数预测模型R2达0.85,预测效果均可满足农田电导率估算,但对数模型在土壤电导率较低区间预测效果不理想,因此土壤电导率指数预测模型预测效果优于对数模型的预测效果。研究结果表明,土壤光谱反射率预测土壤电导率的方案可行,并为光谱信息预测土壤电导率提供了新思路。 相似文献
13.
Allan Fulton Larry Schwankl Kris Lynn Bruce Lampinen John Edstrom Terry Prichard 《Irrigation Science》2011,29(6):497-512
Orchard and vineyard producers conduct preplant site evaluations to help prevent planting permanent tree and vine crops on
lands where the crop will not perform to its highest potential or attain its full life expectancy. Physical soil characteristics
within specific soil profiles and spatially throughout an orchard influence decisions on land preparation, irrigation system
selection, horticultural choices, and nutrient management. Producers depend on soil surveys to help them understand the soil
characteristics of the land and may be interested in technology that provides additional information. Electromagnetic induction
(EM38) and four-probe soil resistance sensors (VERIS) are being used in combination with global positioning systems to map
spatial variability of soils using apparent soil electrical conductivity (ECa). The hypothesis evaluated in this study is
whether rapid, in situ, and relatively low-cost methods of measuring ECa (EM38 and VERIS) can effectively identify and map
physical soil variability in non-saline soils. The supposition is that in non-saline soils, ECa levels will relate well to
soil texture and water-holding capacity and can be used to map physical soil variability. In turn, the information can be
used to guide decisions on preplant tillage, irrigation system design, water and nutritional management, and other horticultural
considerations. Two sites in the Sacramento Valley were mapped each with EM38 and VERIS methods. Site-specific management
zones were identified by each provider on ECa maps for each site, and then soil samples were collected by University of California
researchers to verify these zones. Results showed that on non-saline soils, ECa measured with both EM38 and VERIS correlate
with physical soil properties such as gravel, sand, silt, and clay content but the relationship between conductivity and these
physical soil properties varied from moderately strong to weak. The strength of the correlation may be affected by several
factors including how dominant soil texture is on conductivity relative to other soil properties and on methods of equipment
operation, data analysis and interpretation. Overall, the commercial providers of ECa surveys in this study delivered reasonable
levels of accuracy that were consistent with results reported in previous studies. At one site, an ECa map developed with
VERIS provided more detail on physical soil variability to supplement published soil surveys and aided in the planning and
development of a walnut orchard. At a second site, almond yield appeared to correlate well with distinctly different soil
zones identified with EM38 mapping. 相似文献
14.
The 2004 Indian Ocean tsunami inundated about 37,500 ha of coastal farmland in Aceh, and crops planted after the tsunami were severely affected by soil salinity. This paper describes the changes of soil salinity over time on tsunami affected farms and the implications for resuming crop production after natural disasters.Soil salinity and salt leaching processes were assessed across the tsunami affected region by measuring soil apparent electrical conductivity (ECa) using an electromagnetic induction soil conductivity instrument (EM38) combined with limited soil analysis. The ECa was measured 5 times between August 2005 and December 2007 in both the vertical (EMv) and horizontal (EMh) dipole orientations at 23 sites across Aceh. The level of salinity and direction of salt movement were assessed by comparing changes in mean profile ECa and relative changes in EMv and EMh.Eight months after the tsunami the average soil salinity in the 0-1.2 m soil depth varied from ECe 22.6 to 1.6 dS m−1 across sites in the affected region and three years after the tsunami it varied from 13.0 to 1.4 dS m−1. Soil salinity tended to be higher in rice paddy areas that trapped saline tsunami sediments and held seawater for longer periods. Leaching of salts occurred slowly by both vertical displacement and horizontal movement in surface waters. Hence, soil salinity persisted at a level which could reduce crop production for several years after the 2004 tsunami. High soil salinity persisted three years after the tsunami even though there had been more than 3000-7000 mm of accumulated rainfall to leach salts. The slow leaching is likely to have been due to the loss of functional drainage systems and general low relief of the affected areas.Monitoring of soil salinity with EM38 assisted local agricultural extension agencies to identify sites that were too saline for crops and determine when they were suitable for cropping again. The methodology used in this study could be used after similar disasters where coastal agriculture areas become inundated by seawater from storm surges or future tsunamis. 相似文献
15.
为了揭示研究区域林地内土壤含水率和电导率的空间分布特征及尺度效应,利用多重分形方法,对杨凌一林地内不同采样时间和不同采样面积下土壤含水率和电导率的空间异质性进行了研究。结果表明：3种采样面积下土壤含水率和电导率的空间异质性都分别随平均含水率和电导率的增大而减弱。随采样面积的增大,平均含水率和电导率较高时,土壤含水率的空间异质性趋于增强,土壤电导率的尺度效应不明显;平均含水率和电导率较低时,土壤含水率和电导率的空间分布都存在明显的斑块结构。不同采样时间和不同采样面积下土壤含水率和电导率的多重分形谱的形态有所差异,表明引起他们空间异质性的信息有所不同。多重分形分析能揭示出较多的采样林地内土壤含水率和电导率分布的局部信息。 相似文献
16.
Mohammad Monirul Islam Timothy Saey Eef Meerschman Philippe De Smedt Fun Meeuws Ellen Van De Vijver Marc Van Meirvenne 《Agricultural Water Management》2011,102(1):8
Paddy rice fields are kept inundated during most of the growing period. This requirement is challenging to achieve because of the lack of suitable technologies to detect rapidly percolation prone zones within these fields. The objective of this study was to evaluate a methodology to identify water leakage areas to support precision soil–water management at a within-field level. Therefore, a Floating Sensing System (FloSSy) was designed to record the soil apparent electrical conductivity (ECa) of a paddy field both under dry and inundated conditions using the electromagnetic induction sensor EM38. Comparison of ECa data sets obtained under inundated and dry conditions showed that the ECa measurements under inundated condition (ECa-i) were more strongly related to soil properties due to the absence of variability in soil moisture and the increased stability of the floating sensing platform. Therefore, we proceeded with the ECa-i measurements and grouped them into two classes using a fuzzy k-means classification method. These classes showed significant differences in water infiltration: lower ECa values represented a higher infiltration rate and vice versa. This effect was attributed to differences in soil texture, more specifically the sand content, and its effect on water retention. It was concluded that an ECa-i survey with FloSSy allowed the detection of soil heterogeneity linked to downward water fluxes which has a potential to support precision soil–water management in inundated fields. 相似文献