A MODEL FOR IRRIGATION SCHEDULING WITH SALINE WATER

Sahar  N. HUSSEINI

Investigations into the literature have shown the lack of research into the comparison between the effect of matric and osmotic potential, which represent water and salinity stress respectively, on yield. Studies have therefore been performed in order to elucidate the relationship between these variables. Analysis of wheat experimental data has shown that there was no statistical significance between the effect of matric potential and osmotic potential at the time of irrigation on yield and evapotranpiration. For practical purposes, therefore, the two variables can be considered as identical in their effect yield and evapotranspiration.

Experimental measurements into the effect of these two potentials on the variation moisture content with time have produced antagonistic results compared with their effect on yield and evapotranspiration. Theoretical modeling of the effect of matric and osmotic potential on the variation of moisture content with time and the average evapotranspiration response over each irrigation interval has explained the experimental findings.

Using the above results, a computer model in C++ was developed for irrigation scheduling with saline water. At present, the model is specific to the wheat crop used in the current experimental study. The model is applicable to all soil types and has scope for further development to include all crops.