Maize Response to Salinity Stress Using Water Uptake Models in Different Seasons

This study was performed to investigate the effect of salinity stress and evaporative demand on water uptake by maize (Zea Mays L.). For two seasons, greenhouse experiments were conducted in pots in a completely randomized design with 4 replicates in 2017. Water uptake by maize was measured daily under constant matric suction of 100 cm at different salinity levels (0, 1.7, 3.36, 6.33 and 8.35 dS/m). The electrical conductivity in pots was kept constant after the treatment initiations. The salinity threshold level was determined to be 0.52 for spring season and 1.48 dS/m for autumn season based on salinity of irrigation water which implies more sensivity of maize to salinity stress under high evaporative demand as compared to low evaporative demand conditions. The imposed salinity stress significantly affected water uptake and yield in both spring and autumn seasons. The estimated yield and water uptake values using reduction functions indicated that the exponential model of van Genuchten-Hoffman had more accuracy than the linear model of Maas-Hoffman for yield, while the accuracy of linear model was more than the exponential model for water uptake, especially in autumn season. It is concluded that the plant response to salinity stress is not the same under different evaporative demand conditions.