Texture specific regression models for predicting soil ECe values from EC1: 2.5 for effective soil salinity assessment in Tanzania
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Date
2023
Authors
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Journal ISSN
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Publisher
Tanzania Journal of Agricultural Sciences
Abstract
Electrical conductivity of saturated soil paste extract (ECe) is a standard laboratory soil salinity measurement. However, due to difficulty of ECe measurement, electrical conductivity of soil to water suspensions (ECsoil:water) such as EC1:2.5 are used and its values converted to ECe for salinity interpretation in crop production. This study was conducted to develop texture specific regression models for predicting ECe values from EC1:2.5 for Tanzanian soils. A total of 198 composite soil samples at 0 – 30 cm depth were collected from Kiwere, Dakawa, Sakalilo and Mwamapuli irrigation schemes in Iringa, Morogoro, Rukwa and Katavi Regions respectively and analyzed for soil texture, EC1:2.5 and ECe using standard laboratory methods. The dominant soil textural classes were clay, sandy clay loam, sandy clay, and clay loam. There were significant differences (P<0.05) between mean values of EC1:2.5 and ECe (dS m-1) in all textural classes. The regression models indicated significantly strong linear relationships between values of EC1:2.5 and ECe for all textural classes with R2>0.90 and P<0.001 for both regression models with and without intercept. The regression models without intercept performed better in predicting soil ECe from EC1:2.5 than regression models with intercept by having higher P-values, slope value closer to 1.0 and lower RMSE values between measured and predicted ECe. The study recommends regression models expressed as ECe = 2.0963 EC1:2.5 for clay; ECe = 2.7714 EC1:2.5 for sandy clay loam; ECe = 2.3519 EC1:2.5 for sandy clay and ECe = 2.0811 EC1:2.5 for clay loam soils for predicting soil ECe from EC1:2.5 in Tanzania.
Description
Journal article pg. 54-61
Keywords
Soil salinity, regression models, EC1:2.5, ECe, Tanzania
Citation
https://www.ajol.info/index.php/tjags/article/view/263059