a1 Crop Science Department, University of Science and Technology, Kumasi, Ghana
a2 Forestry Research Institute of Ghana, University of Science and Technology, Kumasi, Ghana
a3 Institute of Renewable Natural Resources, University of Science and Technology, Kumasi, Ghana
Pot and field experiments were conducted at the Faculty of Agriculture Arable Crops Farm, Kumasi, Ghana during the major rainy season to compare the agronomic efficiency of potassium in cocoa pod ash with that of muriate of potash and to determine the optimum rate of application of cocoa pod ash to maize (Zea mays L. cv. La Posta). Results from the two experiments indicated that the application of 90 kg N/ha and 67 kg P2 O5/ha did not increase shoot dry matter (DM) yield over the control. However, significant increases in DM yield over the control were obtained when N and P were applied together with 56 kg K2O/ha, demonstrating the complementarity of the major nutrient elements N, P and K. Shoot and root DM increased with increasing application of cocoa pod ash. Application of 140 kg/ha cocoa pod as (equivalent to 56 kg K2O/ha) produced the same DM and shoot potassium yields as 56 kg K2O/ha as muriate of potash. The optimum rate of application of cocoa pod ash was 280 kg/ha (112 kg K2O/ha).
(Received May 17 1993)
p1 Present address: International Institute of Tropical Agriculture, PMB 5320, Ibadan, Nigeria.
p2 To whom correspondence should be addressed.