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 the first and second experiment, irrigation was performed after 50 mm and 100 mm of evaporation from the Class A evaporation pan, respectively. 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. Water stress resulted in an increase in proline content compared with normal irrigation. Water stress also led to decreased grain yield (30%). The maximum 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).