Conductivity Of Saturation Extract Research Articles

Melon cultivation irrigated with saline waters promote chemical alterations in an acrisol

The objective of the present study was to evaluate the salinization process and the changes in the chemical properties of an Acrisol cultivated with melon irrigated with water of different saline concentrations. The experiment was carried out in the field conditions using the experimental design of randomized blocks, arranged in split-plot. The plots were composed of salinity levels of irrigation water, expressed in terms of water electrical conductivity (ECw): 0.54; 1.48; 2.02 dS m-1; and the sub-plots for melon cultivars: Sancho and Medellín (Toad Skin), Mandacaru (Yellow), Nectar (Galia) and Sedna (Cantaloupe). Soil samples were collected at the beginning and end of the crop cycle to evaluate the changes in the physical-chemical properties of the soil. The electrical conductivity of saturation extract in the soil profile varied for each cultivar, observing high salinity values in soils with cultivars with lower water demand (Sedna and Nectar). The salinity of the soil was lower than the electrical conductivity of the irrigation water in the treatments with high values of ECw. The soil pH values showed little reaction in relation to the initial values. The exchangeable sodium percentage values were approximate twice the sodium adsorption ratio of the saturation stratum.

Physio-chemical properties and dynamic of the surface sediment in riparian mangroves along the Tien river, Tien Giang province

This study was conducted to investigate the physio-chemical properties and vertical dynamic of the surface sediment (0–5 cm) in riparian mangroves along the Tien river, Tien Giang province. The distribution of riparian mangroves located from the polyhaline zone (transect S1 and S2) to the mesohaline zone (transect S3 and S4) and the oligohaline zone (transect S5). Three plots (10x10 m) per transect were set based on the elevation of the mangrove floor (cm + mean sea level) and dominant plants. A total of 28 sediment samples were collected in December 2016 and April 2017. Seasonal variation of pH, redox potential (Eh), electrical conductivity of saturated extract (ECse), bulk density, sediment organic matter (SOM) and total sulfur (TS) were measured in accordance with the standard protocols. Seasonal trends of vertical erosion and accumulation were tested by the tracer stick method. The ECse values and TS concentrations were higher in the dry season and in transects closed to the estuary (S1, S2 and S3) but these trends weren’t found for pH, Eh, and SOM. In most of the riparian mangroves along the Tiền river, low elevation (0–50 cm) was one of important factors affecting the Eh and ECse. In the rainy season, major changes in vertical erosion and acumulation have occurred in the transects near the mouth of the river.

Field-scale Spatial Variability of Electrical Conductivity of the Inland, Salt-affected Soils of Northeast Thailand

Salt-affected soil maps for Northeast Thailand focus on the percentage of salt crusts. Investigation was done to find the field-scale spatial variability of the electrical conductivity of saturation extract (ECe) in salt-affected areas (percentage salt crusts: very severely = class 1; severely = class 2, and moderately = class 3). Two study sites were selected for each class (n = 6). Soil samples (n = 100) were collected at each site using stratified, systematic, unaligned sampling, and analyzed for ECe. Variations in ECe were assessed using basic statistics and geostatistics. At the field-scale, in every class, the best-fit semivariogram model generated was satisfactory (R2 > 0.8). Interpretation from the relevant model parameters (i.e., nugget, sill, and effective range), together with the interpolated (kriged) maps, demonstrated that the characteristics of spatial variability of soil ECe were inconsistent, even between different sites of the same salt-affected soil class. In general, various degrees of small-scale variation were observed, very high variation of ECe was common, spatial dependence was strong to moderate, while the spatial distribution pattern was in distinctive patches. The size of patches depended on the effective range at each site. This study also revealed that the class 1 areas were entirely, very strongly saline (ECes range, 56.70 and 433.00 dS·m-1), whereas the areas of class 3 were non-saline to moderately saline (range, 0.11 - 5.26 dS·m-1). Class 2 areas were much more complex; the soils varied from non-saline to very strongly saline (range, 0.16 - 49.00 dS·m-1). Information on the nature and characteristics in the spatial variability of soil ECe is useful for developing strategies for management of salt-affected soils in precision agriculture in this region.

Chemical attributes of soil and dry mass accumulation of maize fertilized with cassava wastewater

The aim of this study was to evaluate chemical attributes alterations of a clay-loam textured soil and dry mass accumulation of maize submitted to application of cassava wastewater doses in three assessment periods. The experiment was conducted under greenhouse using a completely randomized experimental design in a factorial 5 × 3, with four replicates. The analyzed factors of research were doses of cassava wastewater (0; 12.6; 25.2; 50.4; 75.6 m3 ha-1) andassessment periods (20, 40 and 52 days after germination). The following parameters were determined: electric conductivity of soil saturation extract, pH in water, content of available P, content of exchangeable K+, Ca2+, Mg2+ and Na+ of soil, dry mass of leaves and stem. The application of cassava wastewater on soil enables increase of pH, electric conductivity of saturation extract, contents of available P, contents of exchangeable K+ and Na+ and dry mass of leaves and stem. However, only pH and content of exchangeable K+ of soil, the electric conductivity of saturation extract and dry mass of leaves and stem are influenced by assessment period.

Concentration of injetion solution and its effects on soil and on yield of fertirrigated banana cv. Terra Maranhão

The Fertigation is the combined application of water and nutrients to a crop. It can be adapted to all types of agricultural crops. The objective of this study was to evaluate the effect of urea concentration in irrigation water on electrical conductivity of the soil solution and saturation extract along the first cycle of banana cv. Terra Maranhão. The experiment followed a completely randomized design with six treatments and ten replications. Treatments regarded for using three urea concentrations (1.0; 2.5 and 4.0 g L-1) in irrigation water applied by two micro irrigation systems (microsprinkler and drip). Results showed that there was a linear elevation of electrical conductivity of saturation extract and soil solution with the increase on concentration of urea in the injection solution. Urea should be used under concentrations up to 2.5 g L-1 in irrigation water without causing increase on electric conductivity of soil solution and saturation extract, considering 1.1 dS m-1 as the tolerated value for the crop. Nitrate in the soil solution increased significantly with the increase of urea concentration in the injection solution. The maximum concentration of nitrate in the soil occurred for 4,0 g L-1 concentration of the injection solution.

Phosphorus and Zinc Requirement of Rice under Saline Condition

A green house experiment was conducted for two consecutive years to study the phosphorus and zinc requirement of rice, irrigated with saline water. Three levels of water salinity viz. control (S0), 8.0 (S1) and 16.0 (S2) dSm−1 electrical conductivity (EC), three levels of phosphorus 40 (P1), 80 (P2) and 120 (P3) kg ha−1 and four levels of zinc sulphate (ZnSO4) viz. control (Zn0), 25 (Zn1), 50 (Zn2) and 75 (Zn3) kg ha−1 were tested in a factorial completely randomized design. Saline water having EC 16 dSm−1 decreased the plant height, number of tillers plant−1 and grain yield by 18.2, 24.0 and 52.3% during 1st year and 18.73, 22.13 and 51.63%, respectively during 2nd year of experimentation. Phosphorus application @ 80 kg ha−1 increased grain yield to extent of 19.12 and 29.02% during 1st and 2nd years over 40 kg ha−1 dose of phosphorus while ZnSO4 @ 50 kg ha−1 increased grain yield by 46.29 and 43.33% during 1st and 2nd year over control, respectively. On the basis of grain yield, positive interaction indicated that 95.10 kg ha−1 phosphorus and 60.68 kg ha−1 zinc sulphate were found to be optimum doses for getting higher yield of rice under salt stressed condition on sandy loam soils. The N, P, K, Ca, Na and Zn uptake by grain significantly increased up to 50 kg ha−1 ZnSO4 application. The electrical conductivity of saturated extract of soil after experimentation remarkably increased but pH was not affected with water salinity levels. Irrigation with saline water adversely affected the growth and yield of rice and nutrient uptake.

Alterações dos atributos físicos e químicos de um Neossolo após aplicação de doses de manipueira

O resíduo gerado no processamento industrial da mandioca (manipueira) apresenta alta carga orgânica e elevada concentração de nutrientes. Tal resíduo, se descartado indiscriminadamente no solo, pode trazer sérios riscos ao ambiente. Assim, o objetivo deste estudo foi avaliar as alterações dos atributos físicos e químicos em um Neossolo Regolítico cultivado com alface e submetido às diferentes doses de manipueira. O experimento foi conduzido em casa de vegetação e se utilizou um delineamento inteiramente casualizado, com seis tratamentos compostos das seguintes doses: 0, 5, 15, 25, 45, 65 m³ ha-1 com cinco repetições. Para caracterização dos atributos do solo foram determinados parâmetros físicos (grau de floculação, argila dispersa em água) e químicos (condutividade elétrica do extrato de saturação do solo, pH, teor de P e teores de cátions trocáveis K+, Ca2+, Mg2+ e Na+) do solo. A aplicação de manipueira ao solo propiciou um aumento significativo do grau de floculação, do pH, da condutividade elétrica do extrato de saturação, dos teores de cátions trocáveis e do teor de P, além de uma diminuição significativa da argila dispersa em água, constatando-se também tendência à salinização, em virtude do uso da manipueira.

Estimation of Osmotic Suction from Electrical Conductivity and Water Content Measurements in Unsaturated Soils

Abstract Salt-affected soils are a common feature of an arid-zone landscape. Osmotic suction arises from the salt content in the soil pore fluid. In this research osmotic potential was obtained by measuring total and matric suction via the filter paper technique. The filter paper technique has been widely adopted for measuring soil water potential in the recent years and now is a U.S. standard. One thousand and twenty samples of clay, silty clay loam, sandy clay loam, and loam having different levels of soil water content, between the field capacity (F.C.) and permanent wilting point (P.W.P.) defined as the soil water content below which plants wilt permanently, and ten levels of soil salinity were tested. The measuring tests were repeated three times and aimed at measuring the osmotic suction. By stepwise multiple regression analysis, four new empirical relations were obtained to estimate the osmotic suction as a function of soil water content and the electrical conductivity of saturation extracts (ECe).The results also indicate that the estimation of osmotic suction using the filter paper technique is inexpensive, relatively simple, and applicable to wide ranges of soil salinity.

Variabilidade espacial da salinidade de um solo aluvial no semi-árido Paraibano

O objetivo deste trabalho foi estudar a variabilidade espacial do pH da pasta de saturação (pHps), condutividade elétrica do extrato de saturação (CEes) e porcentagem de sódio trocável (PST) de um solo aluvial afetado por sais. Foram coletadas amostras de solo nas camadas 0-20, 20-40 e 40-60 cm, numa área do Projeto de Irrigação Capoeira, localizado em São José do Bonfim, Estado da Paraíba, utilizando-se um esquema sistemático de amostragem numa malha regular de 10 x 15 m. Os dados foram analisados através da estatística descritiva e geoestatística. Verificou-se baixa variabilidade para o pHps (CV < 12 %) e elevada para a CEes e PST (CV > 60 %). Modelos esférico e gaussiano foram ajustados aos semivariogramas das variáveis que apresentaram estrutura de dependência espacial, tendo-se obtido alcances variando de 20 a 40 m. Os mapas de isolinhas da combinação da CEes e PST permitiram visualizar o padrão de variabilidade da salinidade e sodicidade, constituindo-se em uma ferramenta para a definição de estratégias de manejo edáfico e recuperação da área afetada.

Salt tolerance of rice cultivars

The dry matter production and the concentration of nutrients in rice (Oryza sativa L.) cultivars from soil adjusted to different levels of salinity were evaluated under a greenhouse conditions. Soil salinity levels were produced by applying 0.34 mol l−1 solution of NaCl which resulted in the following levels, control (0.29), 5, 10 and 15 dS m−1 conductivity of saturation extract. The effect of salinity on dry matter production varied from cultivar to cultivar.

Seed Germination and Salt Tolerance of Crops in Coastal Alluvial Soils of New Brunswick, Canada

The relative salt tolerance of crops grown on coastal alluvial soils was determined by adding NaCl to the soil to give electrical conductivity of saturated extract (ECe) ranging up to 20 mmhos/cm. Crop germination varied with oats > barley > timothy > clover. Yields equivalent to 70% of those obtained on soil without NaCl added indicated that oats was the most tolerant crop, followed by barley, clover, and timothy. Approximate ECe values at this yield level were 5, 4, 4, and 3 mmhos/cm, respectively. Barley is reported in the literature to be more salt tolerant than oats, but ECe as an indication of salt tolerance of barley was lower than that reported for saline soils of arid zones. The study shows that salt tolerance in coastal alluvial soils is comparable to that of other saline soils.

Correlations between Constituents in Irrigation Waters and Irrigated Soils in Kansas

AbstractSoil and water from 26 sites from north‐central and southwestern Kansas were studied to determine if knowledge of the chemical composition of irrigation water could be used to predict salt and Na accumulation in soil. Samples were collected in the summer of 1958 and 1959.Mean exchangeable Na percentage in irrigated soils can be predicted with reasonable accuracy from constituents in irrigation water using Gapon's equation, soluble Na percentage, or the Na adsorption ratio as the basis for estimation. Exchangeable Na percentage can be estimated with an accuracy of ± 1.8 at the 0.90 probability level for 25 out of the 26 soils.Correlation between conductivity of soil saturation extracts and that of irrigation water was 0.98 when observations were restricted to soils that (a) increased in total salt content upon irrigation and (b) in which conductivity of the saturation extract exceeded that of irrigation water. Maximum irrigation water electrical conductivity used on such soils was 2.28 mmho per cm. For this value, soil saturation extract electrical conductivity could be predicted with an accuracy of ± 0.54 mmhos per cm. at the 0.90 probability level.Electrical conductivity of soil saturation extracts varied from 0.4 to 4.7 mmho per cm. at 25° C. Mean exchangeable Na percentage ranged from 0.1 to 6.2. Irrigation water ranged in conductivity from 0.3 to 4.9 mmho per cm. at 25° C.