Fertilizer integration on cacao cum rubber: implications on cacao growth, yield, disease occurrence and profitability

Abstract

This study was conducted to enhance the growth and yield performance of cacao trees under mature rubber for one (1) fruiting season through the integration of urea and vermicompost. The experimental design was set in factorial Randomized Complete Block Design with a total of 15 treatment combinations. The treatments were three rates of urea (0, 100 and 200 g/tree) and five rates of vermicompost (0, 1.5, 3.0, 4.5 and 6.0 kg/tree). The trunk circumference, leaf length and width, number of pods developed and harvested, pod and bean character, soil OM%, leaf Nitrogen content and prevalence of pest and diseases were evaluated. The application of 200g urea per tree produced significant increase from 4.86 to 8.44 kg (73.66% increase) in weight of harvested pods and from 23.32 to 26.40 g/pod (13.21% increase) dry bean weight and significant decrease in the pod index from 43.39 to 38.45 (11.36% decrease). Moreover, the heaviest and thickest pod husk was obtained from plants applied with 100 grams urea + 1.5 kg vermicompost. The highest mean number of beans/pod was obtained from trees applied with 100 – 200 g urea + 1.5 – 3.0 kg vermicompost.  The soil organic matter content (%) and leaf N was slightly increased by application of fertilizer treatments. Pod borer infestation and nematode population were significantly affected by application of urea and vermicompost. Application of 100 g urea/tree or 3.5 bags/ha gave the highest return of investment and was the most profitable source of nutrient.