COMPARISON OF 1:1 AND 1:2 SUSPENSIONS AND EXTRACTS WITH THE SATURATION EXTRACT IN ESTIMATING SALINITY IN SASKATCHEWAN SOILS

1984 ◽  
Vol 64 (4) ◽  
pp. 699-704 ◽  
Author(s):  
T. J. HOGG ◽  
J. L. HENRY

Electrical conductivity of saturation extracts was related to that of 1:1 and 1:2 (soil:H2O) suspensions and extracts for a wide range of Saskatchewan soils. The conductivity of 1:1 extracts was 1.75 times greater than for 1:1 suspensions and the conductivity of 1:2 extracts was 1.38 times greater than that of 1:1 suspensions. The conductivity of the saturation extract was closely related to all of 1:1 extract or suspension; 1:2 extract or suspension (r = 0.96–0.98). The regression coefficient relating the conductivity of 1:1 and 1:2 extracts and suspensions to that of the saturated paste extract decreased in going from coarse to medium to fine soil textures. The concentrations of Na+, Ca2+ + Mg2+ and Cl− in 1:1 and 1:2 (soil:H2O) extracts were highly correlated with the amounts in the saturation extract (r = 0.93 to 0.99). Key words: Soil salinity, 1:1 and 1:2 suspension and extract, saturated paste

Irriga ◽  
2009 ◽  
Vol 14 (3) ◽  
pp. 383-397 ◽  
Author(s):  
Sergio Oliveira Pinto de Queiroz ◽  
Roberto Testezlaf ◽  
Edson Eiji Matsura

METODOLOGIA PARA AVALIAÇÃO DA SALINIDADE DO SOLO EM AMBIENTE PROTEGIDO  Sérgio Oliveira Pinto de Queiroz1; Roberto Testezlaf2; Edson Eiji Matsura21Departamento de Tecnologia e Ciências Sociais, Universidade do Estado da Bahia, Juazeiro, BA,  [email protected]. 2Faculdade de Engenharia Agrícola, Universidade Estadual de Campinas, Campinas, SP  1 RESUMO Em condições de ambiente protegido a irrigação é essencial e a fertirrigação um agente facilitador do manejo da água e fertilização do solo; todavia, o uso contínuo e nem sempre adequado pode elevar a salinidade do solo, comprometendo o processo produtivo. Este trabalho objetivou avaliar uma metodologia para caracterizar a ocorrência de salinização em cultivos protegidos, usando diferentes métodos para determinação da condutividade elétrica do solo. Em laboratório foram avaliados os equipamentos Sensor Sigma Probe EC1, da Delta-T e extratores de solução do solo à vácuo. Os equipamentos foram utilizados em três solos com diferentes texturas e sob cinco níveis de salinidade: 0, 2, 4, 8 e 12 dS. m-1 a 25° C. Os resultados obtidos pelos métodos avaliados foram comparados ao método do extrato de saturação. O equipamento Sigma Probe EC1, por apresentar melhor correlação com o método de referência na fase laboratorial, foi utilizado nas visitas as propriedades, sob produção em ambiente protegido, na macrorregião de Campinas, revelou ser mais eficiente. A aplicação do questionário associada às leituras de condutividade elétrica do solo com o sensor Sigma Probe permitiu diagnosticar a deficiência no manejo da água e condutividade elétrica nas propriedades avaliadas. Os valores obtidos de condutividade elétrica no extrato de saturação do solo para as propriedades visitadas, não caracterizam solos salinos, mas podem afetar a produção de flores e outras plantas sensíveis à salinidade. UNITERMOS: manejo da irrigação; fertirrigação.  QUEIROZ, S. O. P. de.; TESTEZLAF, R.; MATSURA, E. E. METHODOLOGY FOR SOIL SALINITY EVALUATION IN GREENHOUSE  2 ABSTRACT Under controlled environmental conditions, irrigation is essential and the use of fertigation becomes a facilitator agent for water and fertilization management. However, the intensive use of fertigation in this type of productive process can increase soil salinity, and affect productive process. This work objective was to evaluate a methodology in order to characterize the salinization process occurrence of in greenhouse farms using different methods to determine soil electric conductivity l. Sigma Probe EC1, manufactured by Delta-T and vacuum solution manufactured extractors were evaluated under laboratory conditions. The equipment was used in three different soil textures, under five salinity levels: 0, 2, 4, 8 and 12 dS. m-1 at 25° C. The obtained results of electric conductivity were compared to the saturation extract method. The Sigma Probe EC1 equipment was used in farm visits, with controlled environmental production inCampinas macro region. Among the used equipment in the laboratorial part, the sigma Probe EC1 presented the best results for soil electrical conductivity determination, when compared to saturation extract, in saline and non saline soils. Using the questionnaire for electric conductivity determinations using Sigma Probe sensor it was possible to verify the deficiency in the soil moisture and electrical conductivity management. The obtained results for electric conductivity using the saturation extract methods do not characterize saline soils on the visited farms, but they showed that the salinity levels in the soil could affect flower production and other crops sensitive to salinity. KEYWORDS: irrigation management, fertigation.


1989 ◽  
Vol 69 (1) ◽  
pp. 25-32 ◽  
Author(s):  
R. C. McKENZIE ◽  
W. CHOMISTEK ◽  
N. F. CLARK

Linear equations were developed for converting electromagnetic induction readings (ECa) from EM38 meters to saturated paste electrical conductivity values (ECc). To correlate EM38 readings with measured ECe values, field sites representing a range of salinity conditions were sampled in 0.30-m increments to a depth of 1.5 m. Adapting a weighting procedure based on the EM38 meter's response to depth, ECe values were condensed into a single weighted value. The weighted ECe values were linearly correlated with temperature-corrected ECa readings. Equations were designed for soils of various textures under varying temperature and moisture conditions. For accurate ECa to ECe conversions, soil temperature correction of ECa is essential. When a frozen layer is present, EM38 readings are unreliable. EM38 horizontal and vertical modes show different ECa readings for the same depth-weighted ECe. Variability of ECa to ECe conversion was greater on coarse-textured than medium- or fine-textured soils. Available soil moisture should be above 30% for accurate ECe determinations from ECa readings. Key words: Salinity methods, soil salinity, saturated paste extract method, electromagnetic inductance meters, soil temperature


1979 ◽  
Vol 59 (4) ◽  
pp. 381-385 ◽  
Author(s):  
D. W. L. READ ◽  
D. R. CAMERON

Soil paste electrical conductivity (EC) (mmhos/cm) measurements were correlated with Wenner array conductivities at eight sites. Linear correlation coefficients varied from 0.61 to 0.98. The addition of the independent variables, sand, clay, and water content, improved the relationship on four sites. The largest standard deviation from the regression relationships did not exceed ± 2.9 mmhos/cm (average soil EC near 7.0 mmhos/cm). For most sites soil salinity could be estimated within ± 2.0 mmhos/cm and at certain sites within ± 1.0 mmhos/cm. Although the correlations were not as high as those obtained by others, it was felt the Wenner array technique was still a reasonable approach for assessing and mapping salinity under a wide range of field conditions.


Water ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1589 ◽  
Author(s):  
George Kargas ◽  
Iakovos Chatzigiakoumis ◽  
Athanasios Kollias ◽  
Dimitrios Spiliotis ◽  
Ioannis Massas ◽  
...  

Soil salinization is directly related to the quantity and quality of food production, and often, to increased energy demands for high-quality irrigation water. Reliable monitoring of soil salinity based on a less laborious method than the soil saturated paste (SP) extract methodology is required. In the present study, an attempt is made to relate the electrical conductivity (EC) of the soil saturated paste (SP) extract (ECe) with the EC determined in the 1:1 and 1:5 soil over water mass ratios, (soil:water) extracts (EC1:1 and EC1:5). ECe, EC1:1, and EC1:5 values were obtained for 198 soil samples from five different locations in Greece. The results have shown that strong linear relationships exist between the ECe and the EC1:1 and EC1:5 values (R2 > 0.93), and that the slopes of these linear relationships decreased from coarse to fine soil types. For 123 soil samples, the concentrations of Κ+, Νa+, Ca2+, Mg2+, and Cl− were also determined in the extracts of the three applied methodologies. Ion concentrations in the 1:1 and 1:5 extracts were highly correlated with the respective ion concentrations in the SP extracts. These findings strongly suggest that EC1:1 and EC1:5 values can be safely used for the estimation of ECe.


2014 ◽  
Vol 602-603 ◽  
pp. 1048-1051 ◽  
Author(s):  
Qiang Shen ◽  
Huan Yuan ◽  
Yuan Lu Xiong ◽  
Guo Qiang Luo ◽  
Lian Meng Zhang

Carbon nanofillers/polymer nanocomposites foam with electrical conductivity was a novel functional material. In this study, the CNTs/PMMA nanocomposites were prepared by the combination of ultrasonic dispersion and anti-solvent precipitation method. Then supercritical foaming method was untilized applied to prepare the foams. The morphology and the electrical conductivity of the foams were investigated. The conductivity of the nanocomposites showed a conductor behavior which was increased t from 1×10-6S/cm to 1×10-5S/cm with the CNTs content range from 1 wt.% to 2.5 wt.%. After foaming, the cell size of the foams was below 10 μm while the cell density increased 2~3 orders of magnitude compared with PMMA foams. The produced CNTs/PMMA nanocomposites foams exhibited a wide range electricity conductivity of the nanofiller contents. Key words: structure, electrical conductivity, CNTs, nanocomposites foams


1985 ◽  
Vol 22 (2) ◽  
pp. 249-253 ◽  
Author(s):  
T. J. Hogg ◽  
J. L. Henry

The electrical conductivity analysis of 1:1 (sample: water) suspensions of hydraulic rotary drill cuttings and of auger samples was found to give closely related results. There were no significant differences (P = 0.01) between the two sampling methods. Thus, the electrical conductivity analysis of hydraulic rotary drill cuttings can be used to give a realistic indication of the salinity profile during deep drilling investigations. Key words: auger, soil salinity, electrical conductivity, hydraulic rotary drill.


Author(s):  
Garrison Sposito

A soil is salineif the electrical conductivity of its soil solution as obtained by extraction from a water-saturated soil paste (ECe) exceeds 4 dS m-1. (The measurement of electrical conductivity for a soil saturation extract is discussed in Methods of Soil Analysis,listed under For Further Reading at the end of this chapter.) According to this definition, about a quarter of the agricultural soils worldwide are saline, but values of ECe > 1 dS m-1 are encountered typically in arid-zone soils, which cover almost one-third of the global ice-free land area. Ions released into the soil solution by mineral weathering, or introduced there by the intrusion of saline surface water or groundwater, tend to accumulate in the secondary minerals formed as the soils dry. These secondary minerals typically include clay minerals (Section 2.3), carbonates and sulfates (Section 2.5), and chlorides. Because Na, K, Ca, and Mg are brought into the soil solution relatively easily—either as displaced exchangeable cations or as cations dissolved from carbonates, sulfates, and chlorides—it is this set of four metals that contributes most to soil salinity. The corresponding set of anions that contributes to salinity is CO3, SO4, and Cl. Thus, arid-zone soil solutions are essentially electrolyte solutions containing chloride, sulfate, and carbonate salts of four metal cations. According to Eq. 4.21, an electrical conductivity of 4 dS m-1 corresponds to an ionic strength of 58 mM (log I = -1.841 + 1.009 log4 = 0.0584). This level of salinity is less than 10% of that of seawater (EC = 46.21 dS m-1), but high enough that only crops that are relatively salt tolerant can withstand it. Moderately salt-sensitive crops are affected when the electrical conductivity of a soil saturation extract approaches 2 dS m-1, corresponding to an ionic strength of 29 mM, and salt-sensitive crops are affected at 1 dS m-1 (I = 14 mM). Thus, with respect to crop salinity tolerance, a soil can be judged saline at any saturation extract ionic strength greater than 15 mM if crops are stressed.


1972 ◽  
Vol 52 (3) ◽  
pp. 311-321 ◽  
Author(s):  
K. W. AYRES ◽  
R. G. BUTTON ◽  
E. DE JONG

The relation between soil structure and soil aeration was investigated on undisturbed soil cores from soil horizons exhibiting six distinct kinds of soil structure (prismatic, columnar, blocky, granular, platy, massive) over a broad range of soil texture. Soil aeration was characterized at ⅓ atm suction by measurements of air porosity, relative diffusivity (D/Do) and the rate of oxygen diffusion to a platinum microelectrode (ODR). Aeration was adequate in most of the Chernozemic soil horizons studied; however, aeration in many of the Bnt horizons of the Solonetzic soils was inadequate. Air porosity and D/Do were highly correlated. The regression coefficient for D/Do vs. air porosity for blocky structures was significantly different from that found for the other five structural types. For granular structures a negative correlation was found for ODR vs. air porosity compared with a low positive correlation found for the other structure types.


2021 ◽  
Vol 285 ◽  
pp. 110171
Author(s):  
Sebastián Bañón ◽  
Sara Álvarez ◽  
Daniel Bañón ◽  
María Fernanda Ortuño ◽  
María Jesús Sánchez-Blanco

2021 ◽  
Vol 13 (10) ◽  
pp. 1875
Author(s):  
Wenping Xie ◽  
Jingsong Yang ◽  
Rongjiang Yao ◽  
Xiangping Wang

Soil salt-water dynamics in the Yangtze River Estuary (YRE) is complex and soil salinity is an obstacle to regional agricultural production and the ecological environment in the YRE. Runoff into the sea is reduced during the impoundment period as the result of the water-storing process of the Three Gorges Reservoir (TGR) in the upper reaches of the Yangtze River, which causes serious seawater intrusion. Soil salinity is a problem due to shallow and saline groundwater under serious seawater intrusion in the YRE. In this research, we focused on the temporal variation and spatial distribution characteristics of soil salinity in the YRE using geostatistics combined with proximally sensed information obtained by an electromagnetic induction (EM) survey method in typical years under the impoundment of the TGR. The EM survey with proximal sensing method was applied to perform soil salinity survey in field in the Yangtze River Estuary, allowing quick determination and quantitative assessment of spatial and temporal variation of soil salinity from 2006 to 2017. We developed regional soil salinity survey and mapping by coupling limited laboratory data with proximal sensed data obtained from EM. We interpreted the soil electrical conductivity by constructing a linear model between the apparent electrical conductivity data measured by an EM 38 device and the soil electrical conductivity (EC) of soil samples measured in laboratory. Then, soil electrical conductivity was converted to soil salt content (soil salinity g kg−1) through established linear regression model based on the laboratory data of soil salinity and soil EC. Semivariograms of regional soil salinity in the survey years were fitted and ordinary kriging interpolation was applied in interpolation and mapping of regional soil salinity. The cross-validation results showed that the prediction results were acceptable. The soil salinity distribution under different survey years was presented and the area of salt affected soil was calculated using geostatistics method. The results of spatial distribution of soil salinity showed that soil salinity near the riverbanks and coastlines was higher than that of inland. The spatial distribution of groundwater depth and salinity revealed that shallow groundwater and high groundwater salinity influenced the spatial distribution characteristics of soil salinity. Under long-term impoundment of the Three Gorges Reservoir, the variation of soil salinity in different hydrological years was analyzed. Results showed that the area affected by soil salinity gradually increased in different hydrological year types under the impoundment of the TGR.


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