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

Document Type : Research Paper

Authors

1 Department of Crop Production and Plant Breeding, College of Agriculture, Shiraz University, Shiraz Iran

2 Department of Water Engineering, College of Agriculture, Shiraz University, Shiraz, Iran.

Abstract

SALTMED model has been developed to predict yield, soil salinity and water
content under saline conditions. A two year field experiment was carried out during
2012-13 to calibrate and validate the model for sorghum. Plants were irrigated with
salinity levels of 2, 6, 10 and 14 dS m-1. Results showed that there were significant
differences between the observed and simulated sorghum dry matter (SDM) and
yield. Absolute mean differences between the observed and simulated SDM values
for 2, 6, 10 and 14 dS m-1 were 0.45, 1.53, 0.04 and 1.07 Mgha-1, respectively. Soil
water contents (SWC) were overestimated at different soil depths. Mean
differences between the simulated and observed SWC at 0.0-0.3, 0.3-0.6, 0.6-0.9
and 0.0-0.9 m soil depths were 0.02, 0.04, 0.02 and 0.03 m3m-3, respectively. As
salinity increased the mean differences between the observed and simulated SWC
were increased. There were no significant differences between the observed and
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
Willmott index of agreement value of the observed and simulated ECe at different
soil depth were between 0.92-0.96. It is concluded that following successful
calibration, the SALTMED model could predict soil salinity and SWC with
reasonably good accuracy at different water salinity levels. Although, SALTMED
model reasonably well predicted soil salinity at different soil depth, there was a
weak agreement between the observed and simulated soil water content at different
soil depths. There was a fair agreement between the observed and simulated dry
matter and grain yield at different water salinity levels.

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