Estimation of the Exchangeable Sodium Percentage from the Sodium Adsorption Ratio for salt-affected soils in Bolivia

Author(s):  
Demis Andrade Foronda

<p>In order to obtain a more cost-time efficient way to determine the sodicity of salt-affected soils, this study aims to generate a regression model to predict the Exchangeable Sodium Percentage (ESP) from the Sodium Adsorption Ratio (SAR<sub>e</sub>). Based on a database with 84 soil samples from the High Valley of Cochabamba (Bolivia), two linear models were generated: <em>ESP= 0.9725 SAR + 1.5766 </em>(R<sup>2</sup>=0.85, RSE=4.47) and <em>ESP= 0.9197 SAR + 0.3813 </em>(R<sup>2</sup>=0.71, RSE=0.91)<em> </em>with square root transformation. Subsequently, through a set of 18 testing samples and a T-test of paired samples between the predicted ESP and measured ESP values, the efficiency of the generated models was verified with a value of p= 0.063 and 0.209, respectively, in contrast to p= 0.285 from the US Salinity Lab referential model. To improve the performance of the generated models, could be necessary a stratification according to soil sodicity levels and additional samples for the calibration dataset.</p>

Irriga ◽  
2018 ◽  
Vol 21 (1) ◽  
pp. 25
Author(s):  
Ariovaldo Antonio Tadeu Lucas ◽  
Marcos Vinicius Folegatti ◽  
Sérgio Nascimento Duarte ◽  
Simone Cristina de Oliveira Lucas

WATER SALINITY USED FOR IRRIGATION IN THE MARINS STREAM WATERSHED, BRAZIL  ARIOVALDO ANTONIO TADEU LUCAS1; MARCOS VINICIUS FOLEGATTI2; SÉRGIO NASCIMENTO DUARTE2 E SIMONE CRISTINA DE OLIVEIRA LUCAS3 1Professor Doutor, Departamento de Engenharia Agrícola, Universidade Federal de Sergipe, UFS, [email protected] Doutor, Departamento de Engenharia de Biossistemas, Escola Superior de Agricultura Luiz de Queiroz, ESALQ, [email protected], [email protected] em Biotecnologia de Recursos Naturais, Rede Nordeste de Biotecnologia, Núcleo Universidade Federal de Sergipe, UFS, [email protected]     1 ABSTRACT Water quality is vital to human activities and irrigation is an activity that uses an accentuated volume of this natural resource. An alternative is the use of water with a salinity level that does not cause damage to plants and the environment. This study aimed to assess the salinity of water used for irrigation of vegetables in Ribeirão dos Marins watershed. The water electrical conductivity, Sodium Adsorption Ratio (SAR) and the Exchangeable Sodium Percentage were obtained using the AquaChem program. Water samples used were collected in 2005, and chemical and physical parameters were assessed. Results showed that region three presented risk to salinization, but overall it is possible to conclude that salinity of the water basin has low risk of salinity. Keywords: soil, water quality, vegetables  LUCAS, A.A.T.; FOLEGATTI, M.V.; DUARTE, S.N.; LUCAS, S.C. de O.SALINIDADE DA ÁGUA USADA PARA IRRIGAÇÃO NA BACIA HIDROGRÁFICA DO RIBEIRÃO DOS MARINS, BRASIL     2 RESUMO A qualidade da água é vital para as atividades humanas e a irrigação é uma atividade que utiliza um volume acentuado deste recurso natural. Uma alternativa é a utilização de águas salobras, mas com um nível de salinidade que não cause danos às plantas e ao ambiente. Este estudo teve como objetivo avaliar a salinidade da água utilizada para irrigação de hortaliças na bacia do córrego Marins. A condutividade elétrica da água, a Razão de Adsorção de Sódio (RAS) e a porcentagem de sódio trocável foram obtidos usando o programa AquaChem. As amostras de água utilizadas foram coletadas em 2005, quando foram avaliados os parâmetros químicos e físicos. Os resultados mostraram que em apenas uma região existe risco de salinização; mas no geral, é possível concluir que a salinidade da água da bacia é de baixo risco. Palavras-chave: solo, qualidade da água, hortaliças


Soil Research ◽  
2016 ◽  
Vol 54 (8) ◽  
pp. 949 ◽  
Author(s):  
John McL. Bennett ◽  
Alla Marchuk ◽  
Serhiy Marchuk

With the introduction of the cation ratio of soil stability (CROSS) to replace the sodium adsorption ratio (SAR) on the basis of differential effects of K and Mg to Na and Ca, respectively, there is a requirement for a similar index involving these cations to replace the exchangeable sodium percentage (ESP). The exchangeable dispersive percentage (EDP) is derived and proposed to replace ESP. This paper uses two datasets, one where exchangeable K concentration is relatively high and exchangeable Na low, and a further dataset where Mg dominates the cation exchange capacity. EDP is validated against these datasets and further mathematical investigation of the contribution of Mg to dispersion is undertaken. Mineralogy appears to affect turbidity results at a given dispersive index, and an improved criterion for assessment of Mg effect on dispersivity is presented.


2019 ◽  
Vol 29 ◽  
pp. 1-20
Author(s):  
José Pedro Pérez-Díaz ◽  
Héctor Manuel Ortega-Escobar ◽  
Carlos Ramírez-Ayala ◽  
Héctor Flores-Magdaleno ◽  
Edgar Iván Sánchez-Bernal ◽  
...  

Factors as agricultural development, the presence of important industrial centers and a population of more than 15 million inhabitants in the Lerma River basin generate wastewaters which are poured into the Lerma River course. This study was carried out to evaluate the quality of the Lerma River water and to estimate the risk of salinization and sodification of the irrigated soils in the basin. Electrical conductivity (EC) was less than 1.252 dS m-1 and water was classified as bicarbonated-sodic, with a medium-low risk of salinity-sodicity (C2-S1, C3-S1). The minimum and maximum sodium adsorption ratio (SAR) values were 2.80 mmol L-1 and 7.63 mmol L-1, and the estimated maximum exchangeable sodium percentage (ESP) was 11.42. Based on the results of this research, the Lerma River water may induce salinization and sodification processes in the irrigated soils.


2016 ◽  
Vol 4 (1) ◽  
pp. 32-36 ◽  
Author(s):  
Mohammed M. A. Elbashier ◽  
Mohammed H. A. Ebrahim ◽  
Abdelrahaman A. Musa ◽  
Albashir A. S. Ali ◽  
Moamer A. A. Mohammed

Revista CERES ◽  
2014 ◽  
Vol 61 (5) ◽  
pp. 715-722 ◽  
Author(s):  
Jefferson Luiz de Aguiar Paes ◽  
Hugo Alberto Ruiz ◽  
Raphael Bragança Alves Fernandes ◽  
Maria Betânia Galvão dos Santos Freire ◽  
Maria de Fatima Cavalcanti Barros ◽  
...  

Hydraulic conductivity is determined in laboratory assays to estimate the flow of water in saturated soils. However, the results of this analysis, when using distilled or deionized water, may not correspond to field conditions in soils with high concentrations of soluble salts. This study therefore set out to determine the hydraulic conductivity in laboratory conditions using solutions of different electrical conductivities in six soils representative of the State of Pernambuco, with the exchangeable sodium percentage adjusted in the range of 5-30%. The results showed an increase in hydraulic conductivity with both decreasing exchangeable sodium percentage and increasing electrical conductivity in the solution. The response to the treatments was more pronounced in soils with higher proportion of more active clays. Determination of hydraulic conductivity in laboratory is routinely performed with deionized or distilled water. However, in salt affected soils, these determinations should be carried out using solutions of electrical conductivity different from 0 dS m-1, with values close to those determined in the saturation extracts.


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