Effects of Organic Amendments on Growth, Establishment and Yield of Cacao (Theobroma cacao L) in Southwestern Nigeria

Abstract

Low soil fertility is a major problem of growth and establishment of cacao seedlings, as well as the yield on the field. However, cacao (Theobroma cacao L) is characterized by high nutrient demand particularly N, P, K, Ca and Mg, during establishment. In this study, the manurial potentials of some organic wastes and their effects on growth, development and yield of cacao in Ibadan and Owena soils of Southwestern Nigeria were investigated. The experiments in Ibadan and Owena were Randomized Complete Block Design (RCBD) with 3 replicates. Fertilizers were: Goat Dung (GD), Sunshine Organic and Organo-Mineral Fertilizers (OF and OMF) and NPK 15:15:15 at 0, 200, 400 and 600 kg/ha. The fertilizers were applied to treatment plots one month after cacao seedlings were transplanted using ring method (July, 2011). Four hundred and thirty two (432) plantain suckers were planted at 3 x 3 m spacing as shade crop while 432 cacao seedlings (F3 Amazon) were also transplanted at 3 x 3 m respectively at each experimental site. Top soil samples were analysed with standard methodologies. Data were collected monthly on cacao growth parameters such as plant height, stem diameter, number of leaves and number of branches, commencing at 3 months after transplanting (MAT). The experiments were monitored for 36 months (144 weeks after planting of cacao). Survival count was carried out 12 MAT. Data collected were subjected to statistical analysis using Analysis of variance (ANOVA) and significant means were separated by Tukey’s HSD (P < 0.05) test. Cacao seedlings grown under 600 kg/ha OF application had 100 and 95 percent survival count at Ibadan and Owena respectively. All fertilizer types and rates at Ibadan and Owena significantly increased cacao seedlings height, number of leaves, stem diameter and number of branches, relative to the control plots at 3, 4, 5, 15, 16 and 17 MAT. Goat dung applied at 600 kg/ha gave the highest number of flowers, cherelles and pods at 24 and 36 MAT at Owena. However, there were no yield parameters recorded for Ibadan experiment at 24 and 36 MAT.