Fertilization of black beans with phosphorus and potassium and its residual effect

Abstract

A field experiment with black beans (Phaseolus vulgaris L.) was carried out during the dry season on a alluvial soil in the state of Rio de Janeiro. A complete factorial 5² design was used, with five levels each of phosphorus and potassium fertilizer. A significant linear and cubic response was observed for phosphorus. There was no response to potassium, but rather a tendency of yields to decrease. Phosphorus levels for maximum and economic yields were calculated using a cubic response function. Residual effect was studied in the subsequent rainy season but no effect for phosphorus and linear response to potassium were observed.