Relative efficacy of cocoa pod husk-based compost on growth and nutrient uptake of cocoa seedlings in the nursery

Abstract

The effect of cocoa pod husk-based compost on growth and nutrient uptake of cocoa seedlings was compared with conventional NPK 15-15-15 fertilizer at the nursery in a randomized complete block design experiment. Poly bags were filled with either top soil or compost alone, and also with mixtures of top soil, compost and inorganic fertilizer in various ratios to provide the following treatments: soil alone, compost alone, 1 : 1 soil/compost, soil + fertilizer, 1 : 1 soil/compost + fertilizer, 1 : 2 soil/compost, 1 : 2 soil/compost + fertilizer, 2 : 1 soil/compost, 2 : 1 soil/compost + fertilizer. The fertilizer was added at the rate of 6 g per poly bag. Plant height, girth, leaf area, dry matter yield, and root volume of cocoa seedlings were significantly (P<0.05) affected by the potting media at 24 weeks after sowing. Potting media with the fertilizer additions significantly (P<0.05) produced shorter seedlings with smaller stems and narrower leaves. Root volumes and total dry matter yield of seedlings positively correlated (r = 0.733), and were significantly (P<0.05) higher in soil/compost mixtures than in treatments with fertilizer additions. Irrespective of the potting media, the uptake of N by the seedlings was higher than P and K. However, the addition of fertilizer to the potting media with compost resulted in lower N uptake by the seedlings. The use of compost developed from cocoa pod husk as potting medium or soil amendment for nursing cocoa seedlings enhanced better seedling growth than when used in combination with NPK 15-15-15 fertilizer.