Interaction Effect of Water Stress and Fertilizer on Yield and Water Productivity of Wheat in Saline Condition

In this study, the interaction effect of water stress at different growth stages and NK fertilizer application on yield and water productivity of wheat was investigated in a saline condition. This experiment was conducted in a split plot design, based on a completely randomized block with five irrigation treatments (as main plots) and four fertilizer treatments (as sub plots) with 4 replications in Khosrowshah region of East Azerbaijan province for 3 years (2011-2014). Irrigation treatments comprised of full irrigation (I1), irrigation cut at stage of stem elongation (I2), Irrigation cut at flowering stage (I3), irrigation cut at milk stage (I4) and irrigation cut at milk and dough stage (I5). Fertilizer treatments comprised of N- and K-fertilizer application based on the local recommendation (F1), 30% more than the recommended rate (F2), 30% lower than the recommended rate (F3) and 30% reduction only in N-fertilizer recommended rate (F4). Results revealed that there was a significant difference between I3 and other treatments. Treatments I1 and I3 with 2865 and 2028 kgha-1 had the highest and lowest grain yield, respectively. There was significant differences among the treatments in terms of water productivity. I5 with 1.42 kgm-3 and I3 with 0.71 kgm-3 had the highest and the lowest water productivity (WP) among treatments, respectively. Among fertilizer treatments, F3 had the lowest biomass and WP in terms of biomass yield, whereas there was no significant difference among the other treatments. There was no significant differences among the fertilizer treatments in terms of grain yield, WP, protein and seed nutrients contents (NPK). Based on the obtained results, in the case of limited yield production due to water scarcity and salinity stress, eliminating late season irrigation at milk and dough stages and also application of N and K fertilizer at the recommended rate are suggested.