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SOIL SALINITY AND SODICITY APPRAISAL BY ELECTROMAGNETIC INDUCTION IN SOILS IRRIGATED TO GROW COTTON
Author(s) -
Ganjegunte G. K.,
Sheng Z.,
Clark J. A.
Publication year - 2012
Publication title -
land degradation and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.403
H-Index - 81
eISSN - 1099-145X
pISSN - 1085-3278
DOI - 10.1002/ldr.1162
Subject(s) - sodium adsorption ratio , soil salinity , salinity , soil water , environmental science , irrigation , soil science , dryland salinity , hydrology (agriculture) , agronomy , soil organic matter , geology , oceanography , geotechnical engineering , drip irrigation , soil biodiversity , biology
In the Far West Texas region in the USA, long‐term irrigation of fine‐textured valley soils with saline Rio Grande River water has led to soil salinity and sodicity problems. Soil salinity [measured by saturated paste electrical conductivity (EC e )] and sodicity [measured by sodium adsorption ratio (SAR)] in the irrigated areas have resulted in poor growing conditions, reduced crop yields, and declining farm profitability. Understanding the spatial distribution of EC e and SAR within the affected areas is necessary for developing management practices. Conventional methods of assessing EC e and SAR distribution at a high spatial resolution are expensive and time consuming. This study evaluated the accuracy of electromagnetic induction (EMI), which measures apparent electrical conductivity (EC a ), to delineate EC e and SAR distribution in two cotton fields located in the Hudspeth and El Paso Counties of Texas, USA. Calibration equations for converting EC a into EC e and SAR were derived using the multiple linear regression (MLR) model included in the EC e Sampling Assessment and Prediction program package developed by the US Salinity Laboratory. Correlations between EC a and soil variables (clay content, EC e , SAR) were highly significant ( p ≤ 0·05). This was further confirmed by significant ( p ≤ 0·05) MLRs used for estimating EC e and SAR. The EC e and SAR determined by EC a closely matched the measured EC e and SAR values of the study site soils, which ranged from 0·47 to 9·87 dS m −1 and 2·27 to 27·4 mmol 1/2 L −1/2 , respectively. High R 2 values between estimated and measured soil EC e and SAR values validated the MLR model results. Results of this study indicated that the EMI method can be used for rapid and accurate delineation of salinity and sodicity distribution within the affected area. Copyright © 2012 John Wiley & Sons, Ltd.