The Deficit Irrigation Effect with Salt Water on Yield and Growth Traits of Spinach Plant (Spinacia Oleraceae L.) in an Arid Climate

Due to the severe shortage of fresh water in arid and semi-arid regions, farmers are forced to use deficit-irrigation techniques along with salt water. In order to minimize salinity and water stresses impacts on the yield and yield components of spinach plant, separately and mutually, a pot experiment was performed from November 2, 2018 to January 18, 2019. The experiment was performed as factorial in the form of a completely randomized design with four replications including three irrigation levels (consisting complete irrigation 100% water requirement =W1, W2=75% W1, and W3=50% W1) and three salinity factors (drinking water S1=0.75, S2=4, S3=8 dS/m) in Kashmar's arid climate. The results showed that separate salinity and deficit irrigation stress had a significant effect on the plant traits including the wet weight of aerial part, leaf surface, plant height, stem height, root length, the dry weight of aerial part and the dry weight of the root, but the mutual effect of salinity and deficit irrigation on the mentioned traits was not significant. As salinity and deficit irrigation increased, the morphological properties of the plant decreased; for example, the maximum wet weight of the plant's aerial part was 147.15 grams in the plant related to W1S1 treatment and its minimum was 38.36 grams in the plant related to W3S3 treatment. The results of comparing the average of plant growth traits showed that there was no significant difference between the treatment of 100% water requirement with salinities of 0.75 and 4 dS/m, but in the salinity treatment control (0.75 dS/m) there was a significant difference between various levels of deficit irrigation. In regard to the above results, it can be said that spinach plant is more sensitive to water stress than salinity stress and applying water stress to the plant during the growing season should be avoided