Abstract

Cacao is a major economic crop in West Africa and some other parts of the world and is grown through nursery prior to field establishment. The husk of Coffea species forms over 40% of the matured seeds and is regarded as a waste despite its nutrient composition status. Husks of Coffea arabica and Coffea canephora were degraded using  Trichoderma harzianum, Streptomyces spp. and the combination of these microbes for 1, 15, and 30 days. Each of bio - degraded C. arabica and C. canephora husks was added to a 2 - week old F₃ amazon cacao variety in a nursery experiment laid out in a completely randomized design (CRD). The effect of ameliorated cacao seedling gave positive enhancement of growth performance of cacao in terms of plant height, number of leaves, stem girth and leaf area. The effect of T. harzianum and Streptomyces degraded C. arabica was more evident on cacao growth at 4 weeks after application but T. harzianum and Streptomyces degraded C. canephora significantly enhanced cacao growth performance at termination of the study. The 30-day T. harzianum combined with Streptomyces degraded C. canephora husk showed the best plant height (37.47 mm), number of leaves (27.33), fresh root weight (10.87g) and root thickness (1.57 µm). The highest fresh shoot weight (18.53 mm) was recorded in 30-day T. harzianum combined with Streptomyces degraded C. arabica husk and a day T. harzianum degraded C. canephora husk was the best in fresh plant weight (20.50 g) at the end of the nursery experiment. There were reduced acidity of the soil and an addition of macro nutrients and organic matter contents by the bio-degraded C. arabica and C. canephora husk in the soil. The cacao seedlings were however free of any disease or insect-pest infestation.

Key words: Cacao, amelioration, nursery, soil fertility, coffee husk, bio-degradation.