Effect of Potassium Fertilizer and Foliar Zinc Application on Yield and Quality of Sweet Potato

Field experiments were conducted during the two successive spring seasons of 2008 and 2009 in the International Potato Center (ICP), Agriculture Research Center (ARC), Kafr El-Zayat, El-Gharbia Governorate, Egypt to evaluate the effect of different levels of potassium fertilization and foliar application of different rates of zinc on sweet potato (Ipomoea batatas L) (cv. Abeese ) performance. Four rates of potassium fertilizer (60, 90, 120 and 150 kg K2O/fed.) in the form of potassium sulfate (48% K2O) and four levels of foliar zinc fertilizer (0, 10, 20 and 30 ppm) in the form of zinc sulfate were applied. The individual effects showed that the highest sweet potato yield was obtained from plants received 150 kg K2O/fed., meanwhile the lowest root yield was obtained from control treatment (60 Kg K2O/fed.). On the other hand, the highest zinc dose recorded the highest production of root yield compared with other low doses. The interaction effect between potassium and zinc fertilizer showed the highest value of vegetative growth, yield and quality of roots when potassium and zinc were applied at the highest levels.