PREDICTING TOMATO TRANSPLANT WATER NEED GROWN UNDER DIFFERENT ECS OF NUTRIENT SOLUTION

Today, intensive production of transplants in special nurseries is a developing activity in some countries and Iran. Different factors must be taken in account and controlled well to achieve high quality plants. Suitable irrigation and feeding (fertigation) can probably be considered as the most effective one among the factors. Physical characteristics of growing media, climatological parameters and EC of nutrient solution are involved in managing procedure of fertigation. Plant daily water need must be calculated to enable the manager for good managing. In this experiment we tried to find some equations for predicting plant daily water need under different ECs of nutrient solution. Results showed that selected EC treatments caused some significant differences in plant water use specially in high radiation season. The maximum water uptake was observed in plants received a nutrient solution with an EC of 1.5 ds/m comparing to the others (2.5. 3.5 and 4.5 ds/m). Leaf area had the most significant effect on water use and if this parameter is considered constant, radiation can be considered as the main predicting factor. The possibility of predicting tomato transplant daily water need by obtained equations will be further discussed.