Considering the importance of the bark of cocoa as the main crop residue in cocoa farms, the objective of this study was to make analysis of nutrients from the organic extract obtained by washing the compost of the bark and to evaluate the effect of this extract as potassium fertilizer in soils and growth of cocoa seedlings. The experiment was conducted in a greenhouse with application of extract in the soil, growing in plastic tubes and seedlings of cocoa. The experimental design was in randomized blocks with three replications and experimental units consisting of nine plants grown individually in plastic tubes. The treatments were five K levels: zero, 125, 250, 500 and 1000 mg K dm-3 of soil. After 120 days of the extract application in the soil, it was found that pH, base saturation and Ca, Mg, K, Zn and Mn available increased while the content of Al and Fe were reduced. The results also showed that the dose 1000 mg K dm-3 of soil unbalanced the ratio K/Mg and K/Ca in leaves with reduced growth of seedlings. The application of bark extract increased significantly the available of K in the soil and concentration in plants. Cocoa seedlings showed growth in responses to different levels of K and, considering the easily of manufacture and applying the extract of the cacao bark, there is possible of the use as a source of K in the production of cocoa seedlings.
compost; cocoa seedlings; potassium
