FONTES E DOSES DE BORO NA QUALIDADE DE SEMENTES DE FEIJÃO-COMUM E MAMONA SOB CONSÓRCIO

Abstract

Elevated productivity of castor and common bean in intercropping is obtained with the use of quality seeds, where boron plays an important role in plant nutrition. The objective of the this study was to evaluate the physiological quality of seeds of the common bean and castor grown in intercropping syste ms, subject to different sources and levels of boron. A completely randomized design was used in a 2 x 5 + 2 facto- rial scheme with four replications. Treatments cons isted of two sources of boron (borax = 11% B and bo ric acid = 17% B), combined with five boron doses (0.0, 0.5, 1.0, 2.0 and 4.0 kg ha -1 of B in the soil) in intercropping of the common bean with castor, plus additional treatm ents of common bean and castor in monoculture. It w as concluded that boric acid permitted for acquisition of common bean seeds with the highest germination per- centage when intercropped with castor. Use of the d ose of 1.5 kg ha -1 of boron in the soil resulted in acquisition of seeds of the common bean with vigor of 79% when intercropped with castor, regardless of the boron s ource. Employing 2.3 kg ha -1 of boron, with the source being either boric acid or borax, influenced the vigor of castor seeds produced when intercropped with the common be an. The addition of boron by soil fertilization, in de- pendent of the source used, did not affect the phys iological quality of common bean seeds or castor se eds pro- duced in monoculture.