Potassium Deficiency in Unshaded Amazon Cocoa (Theobroma Cacao L.) in Ghana

Visual symptoms and soil and plant analysis showed that young Amazon cocoa established on clear-felled land was K-deficient. The symptoms were more complicated than previously supposed and did not appear until the trees were four years old ; they became more severe with time. The symptoms appeared when leaf K was in the range 0 5–0 6% and when soil exchangeable K was less than 0 20 me./ioo gm. Mulching and irrigating corrected the deficiency but were expensive. Cocoa needs much K, and therefore applying more K fertilizer, probably up to four times the present rate of 75 lb. K₂O/acre/annum, is probably the best way of correcting the deficiency in cocoa and building up K reserves in cleared forest soils such as the one in this experiment. Foliar spraying of K may also be useful for correcting the deficiency quickly but temporarily.