EM38在黄河三角洲地区土壤盐渍化快速检测中的应用研究

针对目前黄河三角洲地区存在的土壤盐渍障碍问题,以该地区典型地块为研究对象,电磁感应仪EM38检测与田间采样相结合,分析土壤电导率的剖面分布特征,建立磁感式表观电导率与土壤电导率间的回归模型,并对运用电磁感应仪EM38划分土壤盐渍剖面类型进行探讨。结果表明:研究区表层土壤盐分具有较强的表聚性与变异强度,剖面各土层电导率间存在着关联性;土壤电导率与磁感表观电导率EMh、EMv间呈极显著的相关关系和对数相关关系,EMh对浅层土壤电导率的解译精度较高,对深层土壤电导率、EMv的解译精度要高于EMh;利用电磁感应仪EM38可将研究区土壤盐渍剖面准确划分为表聚型、底聚型与均匀型三种类型,其中表聚型与底聚型是研究区最主要的盐渍剖面类型,进一步的统计分析证明了采用电磁感应仪EM38对土壤盐渍剖面的分类结果具有较高的精度与可信度。该结果对研究黄河三角洲地区土壤盐渍化的发生机理、预测与评估该地区土壤盐渍化的发生发展具有重要参考意义。     

基于EM38和遥感影像的土壤表观电导率建模研究

选取阿克苏地区渭干河-库车河绿洲外围的典型盐渍化区域作为研究对象,应用EM38大地电导率仪测量该地区样点表观电导率,选取四种不同的土壤盐分指数,结合同时期的遥感影像建立基于影像波段的土壤盐分指数回归模型,通过统计软件进行相关分析,发现表观电导率与土壤盐分指数S2即(b1-b3)/(b1+b3)的相关性最高,然后将不同层的土壤表观电导率同S2进行曲线拟合,对不同模型的拟合效果进行对比分析,结果表明:增长模型即复合比级数曲线模型的拟合度最高,通过精度验证,模型不适用于灌区,而荒漠区的各层的预测值与实测值相关分析结果都达到显著性水平,利用该模型可进行荒漠地区表观电导率的反演,因此基于电磁感应技术的土壤表观电导率建模研究可以为快速土壤盐渍化监测提供一种新方法。     

EM38在土壤盐分分带中的运用研究

通过分析EM38所测的大地电导率与土水比（1∶5）浸提液电导率之间的相关关系,建立以土壤浸提液电导率（EC）为因变量,大地电导率（EM）为自变量的预测模型。在预测模型建立的基础上,对其精度进行了评定,以确保预测模型在土壤盐分含量预测中的可信度。利用EM38所测的大地电导率来预测土壤中盐分含量,进而分析土壤盐分含量的空间变异性。结果表明：研究区土壤盐分的空间变异特征为表聚性、分带性;并且分析了土壤盐分含量的带状走向,其浅层（0～30 cm）的走向与中层（30～60 cm）、深层（60～90 cm）、底层（90～120 cm）盐带走向的夹角在5°以上,而其他各层相差3°以内,尤其是浅层（0～30 cm）土层的盐分含量走向与植被的带状走向一致,较好地拟合了研究区的地貌变化特征。     

胶东果园土壤电导率的时空分布特征及Kriging估值

应用传统统计学和地统计学方法,分析了2005年4~11月期间烟台农科院苹果园土壤电导率的空间变异性,并进行了Moran’s I系数分析和Kriging估值。结果表明:土壤电导率具有明显的空间变异性,半方差函数和Moran’s I系数分析说明了4月30日、6月29日和11月16日的空间自相关范围较大,相关性较强;4月20日、7月14日和8月16日的变程偏小,空间相关性较弱。土壤电导率的均值和变异系数随时间变化总体上近似呈现出先增加后减小的趋势,在空间分布上不同时期果园表层土壤电导率分布格局差异较大,土壤电导率的破碎化比较严重。     

施用7%草甘膦水剂对土壤盐化和碱化的影响

通过室内盆栽模拟实验,研究了5种浓度的7%草甘膦水剂对土壤盐化和碱化的影响。结果表明,施药后土壤盐度(用电导率表示)、钠碱化度(ESP)、钠吸附比(SAR)、总碱度及pH值都明显增大,且随施药次数的增加,上述各项盐化和碱化指标不断增大;每次施药后,土壤的各项盐化和碱化指标都随施药浓度的升高呈增大趋势。6次施用0.352 g/L的7%草甘膦水剂后,土壤的电导率由施药前的1 010增加为2 460 μS/cm,ESP由2.247％增加为7.983％,SAR由1.576增加为4.305,总碱度由1.443 mmol/L增加为4.485 mmol/L,pH值由6.92变为7.89。虽然土壤各项盐化和碱化指标的变化都还在非盐化和非碱化土范围内,但有盐化和碱化的趋势。     

Soil characteristics and plant distribution in saline wetlands of Oued Righ,northeastern Algerian Sahara

Saline wetlands are rare ecosystems in Saharan areas, which are important for conservation of many endemic and rare plant species. In this study, we investigated five saline wetland sites of the Oued Righ region, located in the northeastern Algeria, to determine the environmental factors controlling the composition and distribution of plant communities. We established a total of 20 transects to measure the vegetation parameters (density and cover) and soil characteristics (electrical conductivity, moisture, pH, CaSO₄, CaCO₃, organic matter, Na⁺, K⁺, Mg²⁺, Ca²⁺, SO₄^2–, Cl^–, NO₃^– and HCO₃^–). A total of 17 plant species belonging to seven families were identified. The natural vegetation was composed of halophytic and hydro-halophytic plant communities, presented specially by the species of Amaranthaceae family. Soils in the studied wetlands were moist, gypsiferous, alkaline, salty to very salty with dominance of chloride and calcium. Results of the Canonical Correspondence Analysis (CCA) showed that community structure and species distribution patterns of vegetation were mainly dependent on soil characteristics, mainly being soil salinity (CaSO₄, K⁺, Ca²⁺ and Cl^–) and moisture. The distribution of plant species was found to follow a specific zonal pattern. Halocnemum strobilaceum was observed to grow in highly salt-affected soils, thus being the more salt-tolerant species. Phragmites communis plants were widely distributed in the study area with a high density at the edges of accumulated water body. Juncus maritimus, Tamarix gallica and Salicornia fructicosa grew in soils that are partially or completely flooded in winter. Suaeda fructicosa, Traganum nudatum, Arthrocnemum glaucum, Aeluropus littoralis, Cressa cretica and Cynodon dactylon were distributed in salty and moist soils away from the open water body. Plants of Zygophyllum album, Limonastrirum guyonianum, Cornulaca monacantha, Cistanche tinctoria, Mollugo nudicaulis and Sonchus maritimus were found in soils with less salty and moisture. They constituted the outermost belt of vegetation in the studied wetlands. This study will provide a reference on introducing the salt-tolerant plant species as a fodder resource in saline habitats and regenerating the degraded saline wetlands.     

土壤中盐分含量对EM38大地电导仪测量精度的影响分析

通过对EM38测量的表观电导率(EM)与土壤浸提液电导率(EC)之间的回归模型的建立,确定其间的最佳回归模型并分析其拟合精度;据此基础上对土壤的含盐量与预测误差之间建立了回归方程。结果表明:土壤(EC)电导率与其表观电导率(EM)之间有显著的相关性,且EM38测量的预测误差和盐分含量之间的模型为对数方程,因此测量较高盐分含量的土壤时会得到较好的预测效果。     

基于主成分分析的宁夏银北地区龟裂碱土盐分特征研究

为探明宁夏银北地区龟裂碱土的盐分状况,并构建滴灌利用龟裂碱土过程中具有代表性和限制性的盐分特征因子,利用经典统计和主成分分析方法对龟裂碱土原状土剖面和滴灌利用下的土壤盐分特征进行了研究。结果表明,龟裂碱土剖面盐分离子含量总体呈现"T"字型分布,0~40 cm土壤SAR值较大,均高于15(mmol/L)0.5,土壤pH值9.5左右;Cl-和Na+是该土壤中最主要的阴阳离子;HCO3-含量在100 cm以下的土层中逐渐增加;土壤可溶性总盐(TSS)与Cl-和Na+的相关性较大,相关系数分别为0.967和0.910(P<0.01),TSS与饱和浸提液电导率(ECe)亦存在着显著的正相关(P<0.01);主成分分析表明影响土壤利用的4个主成分依次为土壤盐化状况、土壤结构状况、土壤碱化特征以及除Na+、Mg2+和Ca2+等离子之外的其它离子含量状况,其累积方差贡献率为87.18%。由此可见,在宁夏银北地区龟裂碱土具有干旱区盐碱土壤盐分表聚特征,在利用过程中仍需要首先降低土壤盐度,通过改变离子组成减小土壤碱度,改善土壤结构。     

宁夏不同类型盐渍化土壤水溶盐含量与其电导率的关系

根据宁夏盐渍化土壤的分布区域,采集了不同类型盐渍化土壤样品(0~20 cm)141个,测定了土壤浸提液电导率与水溶性盐含量及其盐分组成,系统研究了残渣烘干法土壤水溶盐含量与电导率之间的关系。结果如下:(1)土壤水溶性盐分离子阳离子以钠离子含量最高,镁、钙离子含量次之,阴离子以氯离子含量最高,硫酸根离子含量次之;(2)从阴离子组成来看,供试土壤以硫酸盐-氯化物型、氯化物-硫酸盐型和硫酸盐型为主,从阳离子组成来看,以镁钙盐型、钙镁盐型和钠盐型为主;(3)从5种函数模式中筛选出土壤浸提液电导率与其残渣烘干法水溶盐含量之间的最优回归关系,当不区分土壤盐分类型时,可采用二次式(通式)y=0.1609x2+2.9176x-0.0141求解土壤含盐量;当已知土壤盐分类型时,有针对性地选用不同盐分类型最优回归式计算;(4)提出了电导率法测定土壤水溶盐含量校正为残渣烘干法水溶盐含量的关系式。     

Using sequential Gaussian simulation to assess the uncertainty of the spatial distribution of soil salinity in arid regions of Northwest China

Accurately mapping and monitoring the spatial distribution pattern of soil salinity is essential for sustainable soil management and decision-making. The kriging-based interpolation technique is generally used to map the spatial distribution of soil salinity; however, this technique neglects the variation caused by interpolation for each unsampled location. The sequential gaussian simulation (SGS) is an effective tool to collect mapping uncertainties at several locations simultaneously, which is not possible in the kriging-based technique. Soil electrical conductivity has been widely used as an index for soil salinity. Based on 0–100?cm soil profile from 117 locations in the Manas River basin, Northwest China, the SGS algorithm was used to assess the uncertainty of the spatial distribution of soil electrical conductivity. It was found that the SGS algorithm was reliable in reproducing the spatial distribution of soil electrical conductivity. The SGS algorithm reproduced the sample statistics reasonably well. The standard deviations of the samples generated by the SGS algorithm (0.463–0.508 (dS m^?1)) were closer to the actual samples (0.675 (dS m^?1)) than those generated by kriging (0.454 (dS m^?1)). Most of the study area was lightly affected by salinity. Around 30% of the study area was moderately affected, and the heavily affected areas were sporadically scattered across the study area. The spatial uncertainty at multiple point presented a declining trend as the critical probability at a single point increased. The spatial estimation of the soil electrical conductivity in multiple point was more robust than that in the local location because of the low uncertainty.     

伊犁河谷察南灌区土壤盐分空间变异研究

以伊犁河谷察南灌区为研究区,运用EM38电导率仪测定及室内分析相结合的手段,获取土壤电导率值及0~30 cm、30~60 cm、60~100 cm土壤盐分含量。一方面对各土层土壤盐分含量进行了简单的盐渍化分级统计,另一方面应用地统计学方法,对土壤盐分特征因子进行半方差函数分析及空间插值分析。初步研究表明:察南灌区土壤电导率变异系数为1.31,各土层土壤盐分含量变异系数分别为1.31、1.10、1.49,均呈现空间强变异;0~30cm、30~60 cm、60~100 cm土层土壤中,盐化土所占比例分别为25.37%、21.79%、12.11%,形成了比较明显的盐渍化趋势;在空间分布上,土壤电导率及土壤盐分含量自灌区西北至东南方向总体呈现减小的趋势。另外,研究发现灌区各土壤盐分因子具有强烈的空间相关性,空间变异格局主要是结构性因素作用的结果。     

Soil characteristics and plant distribution in saline wetlands of Oued Righ,northeastern Algeria

Saline wetlands are rare ecosystems in Saharan areas,which are important for conservation of many endemic and rare plant species.In this study,we investigated five saline wetland sites of the Oued Righ region,located in the northeastern Algeria,to determine the environmental factors controlling the composition and distribution of plant communities.We established a total of 20 transects to measure the vegetation parameters(density and cover) and soil characteristics(electrical conductivity,moisture,pH,CaSO_4,CaCO_3,organic matter,Na~+,K~+,Mg~(2+),Ca~(2+),SO_4~(2–),Cl~–,NO_3~– and HCO_3~–).A total of 17 plant species belonging to seven families were identified.The natural vegetation was composed of halophytic and hydro-halophytic plant communities,presented specially by the species of Amaranthaceae family.Soils in the studied wetlands were moist,gypsiferous,alkaline,salty to very salty with dominance of chloride and calcium.Results of the Canonical Correspondence Analysis(CCA) showed that community structure and species distribution patterns of vegetation were mainly dependent on soil characteristics,mainly being soil salinity(CaSO_4,K~+,Ca~(2+) and Cl~–) and moisture.The distribution of plant species was found to follow a specific zonal pattern.Halocnemum strobilaceum was observed to grow in highly salt-affected soils,thus being the more salt-tolerant species.Phragmites communis plants were widely distributed in the study area with a high density at the edges of accumulated water body.Juncus maritimus,Tamarix gallica and Salicornia fructicosa grew in soils that are partially or completely flooded in winter.Suaeda fructicosa,Traganum nudatum,Arthrocnemum glaucum,Aeluropus littoralis,Cressa cretica and Cynodon dactylon were distributed in salty and moist soils away from the open water body.Plants of Zygophyllum album,Limonastrirum guyonianum,Cornulaca monacantha,Cistanche tinctoria,Mollugo nudicaulis and Sonchus maritimus were found in soils with less salty and moisture.They constituted the outermost belt of vegetation in the studied wetlands.This study will provide a reference on introducing the salt-tolerant plant species as a fodder resource in saline habitats and regenerating the degraded saline wetlands.     

高寒草甸退化对土壤电导率变化影响的研究

土壤电导率是表征土壤水溶性盐的一个重要指标,可反映土壤盐渍化程度.为了研究高寒草甸退化对土壤电导率的影响,以三江源区未退化高寒草甸和退化高寒草甸为研究对象,系统分析了退化高寒草甸的植被特征和土壤特征与土壤电导率的相互关系.结果表明:高寒草甸退化会对土壤电导率产生显著负影响,且土壤电导率与评价高寒草甸的退化指标植被盖度、...     

The Impact of Long-Term Irrigation on Changes of Ground Water Level and Soil Salinity in Northern Tunisia

The irrigated area of Kalaat Landelous in northern Tunisia is an example of the successful reclamation of 3000 ha of soils affected by shallow ground water levels and salinization. Examination of soil conditions at three key periods during reclamation reveals the reasons for this success. Aspects of irrigation management define these periods, during which measurements were taken of the depth and salinity of ground water over 43 years. An overall salt balance for the irrigated areas was made in order to estimate the risk of salinization. The results reveal a lowering of the ground water level (average depth was 1 m and will be 1.6 m), desalinization of the soils (average electrolytic conductivity of the soil was 0.8 Sm -1 and will be 0.55 m -1 ), and dilution of the salt content of the ground water (average electrolytic conductivity of ground water was 3 Sm -1 and will be 1.4 Sm -1 ). A reduction in the variability of saline conditions was also observed. The salt balance shows a large amount of salt exported from the area, between 22,000 and 66,000 Mg, and only small areas of new salinization have appeared as a result of irrigation. Ultimately, the sustainability of the project depends upon the performance of the drainage network and on the abundance of the rainfall. If drainage is efficient, soil salinity will be maintained below wheat, corn, tomato, pepper, and alfalfa tolerance limits.     

施用10％草甘膦水剂对土壤环境的影响

本文通过三地田间试验,研究了长期施用草甘膦水剂对土壤性质的影响。结果表明,湖北罗田、潜江和广水三地土壤的电导率、钠碱化度、钠吸附比、pH值和总碱度均呈现增加的现象,虽然根据国内对盐碱土的分类标准指标三地均属于非盐化和碱化土,但有盐化和碱化的趋势。     

吉林省大安市苏打碱土含盐量与电导率的关系

分别测定了吉林省大安市苏打碱土含盐量与电导率以及地下水含盐量与电导率,分析了含盐量与电导率的关系。结果表明,土壤含盐量与电导率、地下水含盐量与电导率之间具有良好的线性相关性,土壤浸出液电导率(y)与土壤含盐量(x)之间的回归方程为:y=0.201 0.092x(r=0.991,n=50,p<0.0001);地下水电导率(y)与含盐量(x)之间的回归方程为:y=-0.393 1.523x(r=0.997,n=18,p<0.0001)。利用方程计算的土壤含盐量与实测值之间符合较好,相对误差大多在7%以下;根据电导率计算的地下水含盐量与实际测量值之间的相对误差一般在5%以下。说明在数据统计分析基础上建立的这两个经验公式适用性较好,可以用于该区苏打碱土土壤及地下水电导率与含盐量之间的换算。     

Spatio-temporal variations of soil water content and salinity around individual Tamarix ramosissima in a semi-arid saline region of the upper Yellow River,Northwest China

Ecological restoration by Tamarix plants on semi-arid saline lands affects the accumulation, distribution patterns and related mechanisms of soil water content and salinity. In this study, spatio-temporal variations of soil water content and salinity around natural individual Tamarix ramosissima Ledeb. were invetigated in a semi-arid saline region of the upper Yellow River, Northwest China. Specifically, soil water content, electrical conductivity(EC_e), sodium adsorption ratio(SAR_e), and salt ions(including Na~+, K~+, Ca~(2+), Mg~(2+) and SO_4~(2–)) were measured at different soil depths and at different distances from the trunk of T. ramosissima in May, July, and September 2016. The soil water content at the 20–80 cm depth was significantly lower in July and September than in May, indicating that T. ramosissima plants absorb a large amount of water through the roots during the growing period, leading to the decreasing of soil water content in the deep soil layer. At the 0–20 cm depth, there was a salt island effect around individual T. ramosissima, and the EC_e differed significantly inside and outside the canopy of T. ramosissima in May and July. Salt bioaccumulation and stemflow were two major contributing factors to this difference. The SAR_e at the 0–20 cm depth was significantly different inside and outside the canopy of T. ramosissima in the three sampling months. The values of SAR_e at the 60–80 cm depth in May and July were significantly higher than those at the 0–60 cm depth and higher than that at the corresponding depth in September. The distribution of Na~+ in the soil was similar to that of the SAR_e, while the concentrations of K~+, Ca~(2+), and Mg~(2+) showed significant differences among the sampling months and soil depths. Both season and soil depth had highly significant effects on soil water content, EC_e and SAR_e, whereas distance from the trunk of T. ramosissima only significantly affected EC_e. Based on these results, we recommend co-planting of shallow-rooted salt-tolerant species near the Tamarix plants and avoiding planting herbaceous plants inside the canopy of T. ramosissima for afforestation in this semi-arid saline region. The results of this study may provide a reference for appropriate restoration in the semi-arid saline regions of the upper Yellow River.     

Soil properties that determine the mortality and growth of Haloxylon aphyllum in the Aral region,Kazakhstan

Black saxaul (Haloxylon aphyllum) is a native tree species tolerant of aridity and salinity. It is planted to alleviate environmental damage due to the formation of the Aralkum desert and improve vegetation of the Aral Sea region. To investigate the environmental factors that determine seedling mortality and growth after rooting, we focused on soil properties and topographic factors in a study plot. We found that a hard clay layer that was low in hydraulic conductivity underlay accumulated sandy sediments at different depths. The soil in low seedling mortality areas was consistently sandy and low in salinity from the surface to a depth of 100 cm. In areas of high seedling mortality (75–100%), soils with a high content of silt and clay, with high salinity were detected within 100 cm depths. This suggests that accumulated sand sediment over a depth of 100 cm is required for root development. Plant height was positively correlated with depth of the hard clay layer. Significant relationships with plant height were also detected in chemical and physical properties at 80–100 cm such as electric conductivity (ECe), sodium adsorption ratio (SAR), and sand ratio. However, these properties had no significant relationship at 0–20 cm or with the relative elevation of the plot, suggesting that the subsequent growth of seedlings depends more on the sub-soil environment than on-surface conditions. The assessment of sub-soil condition is recommended to make site selection for reforestation much more reliable.     

EM38大地电导仪的应用研究

EM38大地电导仪能快速、便捷的进行土壤含盐量的测定,EM38仪器的电磁感应灵敏度随仪器距地高度的增加而减小。EM38的EMv、EMh与5～15cm、15～25cm土层含盐量的相关性要高于与0～5cm土层含盐量的相关性;以EM38仪器在距地表20cm时的EMh、距地表100cm以下的EMv,建立对耕层含盐量的测定模型,能较为准确地对耕层含盐量进行测定。为提高准确度,除含盐量以外,要确保其它各因素的相对一致性。     

基于去包络线和连续投影算法的枣园土壤电导率光谱检测研究

选取新疆阿拉尔市典型极端干旱区为研究对象,利用土壤高光谱特征对土壤电导率进行反演。为了准确快速检测土壤电导率,通过获取南疆阿拉尔市红枣种植区土壤电导率和高光谱信息,在去包络线处理基础上,分别采用相关性分析法和连续投影算法（SPA）筛选特征波长,并建立特征波长与土壤电导率的偏最小二乘回归模型,使用均方根误差(RMSE)、决定系数（R²）以及相对分析误差（RPD）对不同处理方法的模型效果进行评价。结果表明,基于原始光谱直接使用相关性分析法的预测精度RMSE=0.85566,R²=0.7479,RPD=2.7569;通过去包络线处理使用相关性分析筛选特征波长后,模型的预测精度RMSE=0.44490,R²=0.9500,RPD=6.4510;基于原始光谱使用SPA选择特征波长后,模型的预测精度RMSE=0.31178,R²=0.9707,RPD=8.4445;通过去包络线处理使用SPA选择特征波长后,模型的预测精度RMSE=0.30173,R²=0.9764,RPD=9.3215。综上,说明SPA方法具有较强的特征波长选择能力,基于去包络线处理+SPA的偏最小二乘回归反演模型的预测精度最好,可实现新疆阿拉尔地区土壤电导率的快速检测。