Effect of microelements on some physiological traits and yield of soybean (Glycine max L.) under water deficit stress conditions

In order to investigate the effect of foliar application of iron (Fe), zinc (Zn) and boron (B) on grain yield and some physiological characteristics of soybeans under water stress, two separate experiments were conducted in a randomized complete block design with eight treatments in three replications in Aleshtar, Lorestan, during 2013-2014 and 2014-2015. In one experiment, irrigation was performed after 50 mm of evaporation and in the second experiment, irrigation was performed after 100 mm of evaporation from the Class A evaporation pan. Experimental treatments included: spraying of pure water, Zn, Fe, B, Zn + Fe, Zn + B, Fe + B and Zn + Fe + B. The results of variance analysis showed that the effects of irrigation and foliar application were significant on grain yield, proline content, soluble sugars, chlorophyll a, chlorophyll b, PWC and anthocyanin. The water stress resulted to increase proline content under water stress condition compared with normal irrigation. Water stress also was led to decrease grain yield (30%). The most grain yield was related to normal irrigation treatment (2070.5 kg.ha-1) and foliar application of Zn + Fe + B (2200.1 kg.ha-1).