Evaluation of the SALTMED model for sorghum under saline conditions in an arid region

Abstract

<span>SALTMED model has been developed to predict yield, soil salinity and water<br /><span>content under saline conditions. A two year field experiment was carried out during<br /><span>2012-13 to calibrate and validate the model for sorghum. Plants were irrigated with<br /><span>salinity levels of 2, 6, 10 and 14 dS m<span>-1<span>. Results showed that there were significant<br /><span>differences between the observed and simulated sorghum dry matter (SDM) and<br /><span>yield. Absolute mean differences between the observed and simulated SDM values<br /><span>for 2, 6, 10 and 14 dS m<span>-1 <span>were 0.45, 1.53, 0.04 and 1.07 Mgha<span>-1<span>, respectively. Soil<br /><span>water contents (SWC) were overestimated at different soil depths. Mean<br /><span>differences between the simulated and observed SWC at 0.0-0.3, 0.3-0.6, 0.6-0.9<br /><span>and 0.0-0.9 m soil depths were 0.02, 0.04, 0.02 and 0.03 m<span>3<span>m<span>-3<span>, respectively. As<br /><span>salinity increased the mean differences between the observed and simulated SWC<br /><span>were increased. There were no significant differences between the observed and<br /><span>simulated soil salinities at 0.0-0.3, 0.3-0.6, 0.6-0.9 and 0.0-0.9 m soil depths. The<br /><span>Willmott index of agreement value of the observed and simulated EC<span>e <span>at different<br /><span>soil depth were between 0.92-0.96. It is concluded that following successful<br /><span>calibration, the SALTMED model could predict soil salinity and SWC with<br /><span>reasonably good accuracy at different water salinity levels. Although, SALTMED<br /><span>model reasonably well predicted soil salinity at different soil depth, there was a<br /><span>weak agreement between the observed and simulated soil water content at different<br /><span>soil depths. There was a fair agreement between the observed and simulated dry<br /><span>matter and grain yield at different water salinity levels.</span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span><br /><br class="Apple-interchange-newline" /></span></span></span></span></span></span></span></span></span></span></span></span></span>