POTASSIUM AND ZINC CO-FERTILIZATION PROVIDES NEW INSIGHTS TO IMPROVE MAIZE (ZEA MAYS L.) PHYSIOLOGY AND PRODUCTIVITY

Potassium (K) and Zinc (Zn) are essential nutrients, and play key role in many physiological processes. The current study aims to identify their interactive impacts (i) in soil and plant body, (ii) on maize physiology and (iii) on production. A field experiment was conducted to assess the potassium co-fertilization with zinc sources and doses. The treatments were (kg ha(-1)) as: K0 +Zn0, K0 + Zn16, K0 + Zn24, K60 +Zn0, K60 +Zn16, K60 +Zn24, K100 + Zn0, K100 + Zn16 and K100 + Zn24. Murate of potash (MOP) for K, Chelated Zinc (Zn-EDTA; S1) and Zinc Sulphate (ZnSO4; S2) were the sources of Zn fertilization. Results revealed that co-fertilization have significantly improved maize productivity, and physiological traits. Plant height was significantly increased (27%), cob length (50%), 1000-grain weight (25%), dry weight (203%), membrane stability (191%), relative water content (170%), photosynthesis rate (237%), transpiration rate (353%), stomatal conductance (254%), internal CO2 (105%) and chlorophyll contents (185%) with MOP + Zn-EDTA fertilization at K60 + Zn16 treatment as compared to control. Moreover, straw K and grain K contents were also improved with combined K and Zn fertilization, while straw and grain Zn was higher with sole Zn application. It is concluded that co-fertilization of MOP + Zn-EDTA at K60 + Zn16 (kg ha(-1)) is beneficial for productivity, and physiological traits of maize in calcareous soils.