scholarly journals Evaluation of Salt Affected Soils for Rice (Oryza Sativa) Production in Ndungu Irrigation Scheme Same District, Tanzania

2016 ◽  
Vol 6 (1) ◽  
pp. 24 ◽  
Author(s):  
Joel L. Meliyo ◽  
Sophia Kashenge-Killenga ◽  
Kongo M. Victor ◽  
Benjamin Mfupe ◽  
Samwel Hiza ◽  
...  
Keyword(s):  
Farmyard Manure ◽  
Salt Content ◽  
Laboratory Analysis ◽  
Exchangeable Sodium Percentage ◽  
Exchangeable Sodium ◽  
Management Options ◽  
Project Area ◽  
Salt Affected Soil ◽  
Sodium Percentage ◽  
Salt Affected Soils

A study was carried out to examine distribution of salt affected soils by types and extent in the Ndungu Agricultural Development Project (NADP) area of Tanzania. The objective was to generate information to guide salt-affected soil management for sustainable rice production. Conventional methods including use of mini-pits and profile pits, coupled with farmers’ experiences were used to characterise soil. A total of seven randomly selected soil profile pits located in major soils were dug and described. Soil was sampled from natural horizons for laboratory analysis. In addition a total of 158 topsoil (0 – 20 cm depth) composites soil samples were randomly collected from 90 sites of NADP project area for laboratory analysis. Results showed that a few blocks (block is a piece of farm of 6 to 12 acres) had high exchangeable sodium percentage and high levels of bicarbonates, indicating salt-affected soils. Soil pH, exchangeable sodium percentage (ESP), and electrical conductivity of soil paste extract (ECe) values as high as 9.06, 28.7 cmol(+)Nakg-1, and 14dSm-1 were measured. Out of 90 blocks, 10 blocks (11%) showed slight to strong salt effects. Two blocks (2%) has been abandoned, and in some cultivated blocks zero yields were recorded due to salt content. The different levels of salinity development in the project area suggest site-specific remediation and appropriate management options be developed to improve crop production. These include rehabilitation of the irrigation infrastructure, use of farmyard manure as a soil amendment and growing salt-tolerant rice varieties. Furthermore, it is important to create awareness among farmers of the problem of salt-affected soil on rice productivity.

scholarly journals Hydraulic conductivity in response to exchangeable sodium percentage and solution salt concentration

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 ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Hydraulic Conductivity ◽  
Exchangeable Sodium Percentage ◽  
Exchangeable Sodium ◽  
Soluble Salts ◽  
Electrical Conductivities ◽  
Sodium Percentage ◽  
High Concentrations ◽  
Salt Affected Soils

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.

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

2021 ◽  
Author(s):  
Demis Andrade Foronda
Keyword(s):  
Linear Models ◽  
Sodium Adsorption Ratio ◽  
Exchangeable Sodium Percentage ◽  
Exchangeable Sodium ◽  
Paired Samples ◽  
A Value ◽  
Root Transformation ◽  
The Us ◽  
Sodium Percentage ◽  
Salt Affected Soils

<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>

A review of sodicity and sodic soil behavior in Queensland

Soil Research ◽  
1994 ◽  
Vol 32 (2) ◽  
pp. 143 ◽  
Author(s):  
R Shaw ◽  
L Brebber ◽  
C Ahern ◽  
M Weinand
Keyword(s):  
Salt Content ◽  
Clay Mineralogy ◽  
Clay Content ◽  
Particle Packing ◽  
Exchangeable Sodium Percentage ◽  
Exchangeable Sodium ◽  
Soil Behavior ◽  
Sodic Soils ◽  
Wide Range ◽  
Sodium Percentage

The occurrence of sodic soils in Queensland is more related to soil genetic factors of the past than to the current rainfall pattern, with lower sodium accessions and smaller occurrence of saline lands than other areas of Australia. A soil sodicity map of Queensland is presented. On an area basis, 55% of soils in Queensland are non-sodic, 25% are strongly sodic and 20% are of variable sodicity. The map was prepared using exchangeable sodium percentage (ESP) values at 0.6 m depth from 2 009 soil profiles, as well as the soil boundaries of the 1:2000000 Atlas of Australian Soils maps (Northcote et al. 1960-68). There is general agreement with the earlier sodicity map of Northcote and Skene (1972). The relationships between exchangeable sodium and field-measured soil hydraulic properties and plant-available water capacity are discussed. Behaviour of sodic soils depends on the exchangeable sodium percentage, clay content, clay mineralogy and salt levels. The binary component particle packing theory has been used to explain soil behaviour and identify those soils most susceptible to sodium. Cracking clay soils with dominantly smectite mineralogy and high clay contents are less susceptible to a given ESP level, as determined by their hydrological behaviour, than soils of moderate clay content and mixed mineralogies. The sodicity and the salt content of an irrigation water are important in maintaining permeability of soils. The naturally occurring equilibrium salinity-sodicity relationships of a wide range of subsoils in Queensland is compared to the published relationships between stable permeability and decreasing permeability based on sodicity and salt content. Aspects of management of sodicity under dryland and irrigation are discussed.

SOIL AND SOLUTION pH AND SODIUM:CALCIUM RATIO: EFFECTS ON CATION EXCHANGE PROPERTIES OF A SODIUM-SATURATED CHERNOZEMIC SOIL

1984 ◽  
Vol 64 (1) ◽  
pp. 139-146
Author(s):  
THERON G. SOMMERFELDT
Keyword(s):  
Cation Exchange ◽  
Soil Ph ◽  
Irrigation Water ◽  
Polynomial Equation ◽  
Exchangeable Sodium Percentage ◽  
Exchangeable Sodium ◽  
Solution Ph ◽  
Chernozemic Soil ◽  
Sodium Percentage ◽  
Exchange Properties

The effects of soil and solution pH and Na:Ca ratio in solution on the exchangeable Na, Ca, and (Na + Ca) of a Na-saturated Dark Brown Chernozemic soil were studied. At soil pH 9.0, the exchangeable Na, Ca, and (Na + Ca) were 14.5, 25.4, and 21.8% greater than at soil pH 6.0. Solution pH (6.0–9.0) had small but statistically significant effects on the amount of Na and Ca adsorbed by the soil. The logarithm of exchangeable sodium percentage (ESP) was related to the Na fraction in the solution by a polynomial equation, log ESP = 0.93 [Na/(Na + Ca)]2 + 0.16 [Na/(Na + Ca)] + 0.82. Not only is replacement of exchangeable Na with Ca important in the reclamation of this soil, should it become sodic and have a high pH, but also lowering of its surface charge, through lowering of its pH, would be an important factor in its reclamation. It appears impractical to reduce soil pH by applying acidified irrigation water. Acidic amendments such as gypsum and sulfur may be more suitable. Key words: Cation exchange, solution pH, soil pH

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