Effect of Saline Water and Nitrogen Application Management at Different Growth Stages on Wheat Yield

Nitrogen is the primary nutrient that shows deficiency in saline areas, therefore, proper nitrogen fertilizer management is one of the strategies to achieve higher wheat grain yield.  A field experiments in a saline soil was performed on wheat with a factorial arrangement in randomized complete block design with four replications, in Rostagh area, 25 km from Yazd. The first factor was nitrogen sources including urea, ammonium nitrate, and ammonium sulfate fertilizer, and the second factor was fertilizer use management consisting of four levels: 1- control (no nitrogen application), 2- recommended amount of fertilizer in three equal installments at the time of sowing, tillering, and heading stage, 3- recommended amount of fertilizer in three installments and 30% nitrogen in addition to the recommended rate in the tillering stage, and 4- recommended amount of fertilizer in three installments and 30% nitrogen in addition to the recommended rate at the heading stage. The results showed that the additional use of fertilizer at various growth stages had no significant effect on yield and its components.  In comparison of urea to the other two fertilizers, ammonium nitrate had no significant effect in total yield of wheat in different fertilizer treatments, but using 30% nitrogen in addition to the recommended rate at tillering stage could cause significant differences in total yield when ammonium sulfate was used. Based on the results of this experiment, using nitrogen in peak times of consumption i.e. at tillering and heading, can reduce the loss of nitrogen from the soil, in addition to increasing grain and straw yield under saline conditions.