Determination the effects of iron and zinc application on cotton quantity and quality in saline conditions

Cotton is the major world fiber crop. Cotton depends on mineral nutrients for growth and development. Iron and zinc are essential nutrients for profitable cotton production. Studies across the cotton (Gossypium hirsutum L.) growing regions of the Qom and Golestan province have shown the most of soils in these rejoins are saline. Fertilization is of limited value in saline condition. A field experiment was conducted in saline soils of Qom and Golestan provinces to study the effects of Fe and Zn fertilization on the cotton (Gossipium hirsutum L.) yield. The experiment was factorial and conducted in the field as a Randomized Complete Block Design, with 16 treatments, replicated three times in each area under study. The treatments were composed of four level of zinc (O, 10 and 20 kg.ha-1 in soil and foliar application of ZnSO4 with 0.5 percent concentration) and four levels of iron (0, 10 and 20 kg.ha-1 of FEDDHA-138 in soil and foliar application of FeSO4 with 0.5 percent concentration), and finally their means were compared. The results of statistical analysis in Qom area showed that, the individual and combination effect of Fe and Zn application, however increased cotton lint yield, but increases were not significant. In addition to, effects of Fe and Zn fertilization on plant height and number of boll set were not significant. The results of the experiment conducted in Golestanl showed that, only the effect of Zn on plant height was significant ( = 5%) The main effects of Zn, Fe and combination effects of Fe and Zn were not significant. As treatments had not significant effect on number and weight of bolls, thus they had not effect on cotton lint yield. In general, as the amount of Fe and Zn in Golestan soils was upper than critical levels, and in Qom, tested soils had high level of salinity and lint yield were low, therefore Fe and Zn fertilization could not affects on the cotton yield significantly. Additional research is needed to fully understand the benefit of Fe and Zn nutrition on cotton yield under salinity.