Efect of sulfur and zinc fertilizers on physiological characteristics and grain yield of corn (Zea mays L.) under drought stress

Water deficit stress is one of the most important restrictive factors of crop yield. In arid and semi-arid regions of world, the seasonal drought is the most important restrictive factor of development cultivating and corn production. Deficit of nutrients in soil and sufficient inaccessibility to nutrients is from factors that aggravate the drought effects on plant. Therefore, the present experiment was conducted in order to study of the effect of zinc and sulfur fertilizers application levels on physiological characteristics and grain yield of maize under drought stress condition.The results showed that drought stress reduced relative water content of leaf, photosynthesis and grain yield, and with increasing severity of drought stress, amounts of these traits were intensively decreased. The sulfur and zinc fertilizers application increased amount of this traits and decreased percent of cell membrane damage. However, positive effects of zinc on these traits were lesser than sulfur. Sulfur application increased maize grain yield 50% and 45% under full irrigation and severe drought stress, respectively. Results indicated that use of sulfur fertilizer failed to prevent the effect of drought stress on grain yield but largely moderated its effects and thus, sulfur and zinc fertilizers application, especially sulfur can be useful and advisable in full irrigation and deficit irrigation conditions.In order to study of the effect of zinc and sulfur fertilizers application levels on physiological characteristics and grain yield of maize under drought stress condition, an experiment was conducted in research farm of university of Kurdistan in spring of 2009. The experiment was arranged in split-plot factorial based a randomized complete block with four replications. Three irrigation levels, including full irrigation(-2 bar), moderate drought stress(-7 bar) and severe drought stress(-12 bar) was allocated to main plots. Two sulfur application levels, including non-application(control) and application of 30 kg/ha and two zinc application levels as spraying of 1 kg/ha and non-application(control) were considered as sub factors. In order to study of the effect of zinc and sulfur fertilizers application levels on physiological characteristics and grain yield of maize under drought stress condition, an experiment was conducted in research farm of university of Kurdistan in spring of 2009. The experiment was arranged in split-plot factorial based a randomized complete block with four replications. Three irrigation levels, including full irrigation (-2 bar), moderate drought stress (-7 bar) and severe drought stress (-12 bar) was allocated to main plots. Two sulphur application levels, including non-application (control) and application of 30 kg/ha and two zinc application levels as spraying of 1 kg/ha and non-application (control) were considered as sub factors. The results showed that drought stress reduced relative water content of leaf, photosynthesis and grain yield, and with increasing severity of drought stress, amounts of these traits were intensively decreased. The sulphur and zinc fertilizers application increased amount of this traits and decreased percent of cell membrane damage. However, positive effects of zinc on these traits were lesser than sulfur. Sulfur application increased maize grain yield 50% and 45% under full irrigation and severe drought stress, respectively. Results indicated that use of sulfur fertilizer failed to prevent the effect of drought stress on grain yield but largely moderated its effects and thus, sulfur and zinc fertilizers application, especially sulfur can be useful and advisable in full irrigation and deficit irrigation conditions.