Grain N, P, K Concentrations in Wheat as Affected By Potassium and Zinc Sulfate Fertilization to Cope with Drought Conditions

This study has been performed to determine Grain N, P, K concentrations in wheat as affected by potassium and zinc sulfate fertilization to cope with drought conditions in Zahak agricultural research station, at weather condition of Sistan’s area. Experimental design was for two years (2005-2007) with three replications. The water stress included: three irrigation treatments (I1, I2 and I3 are irrigation after 50, 70 and 90% soil water depletion (SWD), respectively), three level of potassium sulfate intake fertilizer (K0, K1 and K2 are Control, 150 and 250 Kg/ha, respectively) and three level of zinc sulfate intake (Z0, Z1 and Z2 are Control, 50 and 80 Kg/ha, respectively). The results showed that the grain N concentrations are not affected by water stress, but, decreased with an increase in potassium consumption. Also, zinc consumption increased the grain N concentration. Increasing zinc consumption caused an increase in N consumption in case of moisture availability (irrigation after 50% soil water depletion). Moreover, the grain phosphorus concentration declined with an increase in zinc consumption, but enhanced by potassium increase of the soil around the roots and hard stress conditions (irrigation after 50% soil water depletion). In this study, continued soil available water depletion up to 90% soil water depletion associated with increased potassium consumption resulted in improved potassium concentration of the grain.