Determinação do período anterior à interferência das plantas daninhas na cultura do feijão-caupi (Vigna unguiculata (L.) Walp) em solo de várzea no estado do Amazonas

Abstract

This study aimed to determine the period of Weed on three cultivars of cowpea (Vigna unguiculata (L.) Walp) in floodplain in the State of Amazonas. The sowing of cowpea was in October 2007 in the conventional system. The experimental design was a randomized complete block with four replications, arranged in subplots. The plots consisted of eleven periods of coexistence between cowpea and weeds at 0, 7, 14, 21, 28, 35, 42, 49, 56, 63 and 70 days after sowing, after these periods, weeds were removed weekly.. Subplots were placed cultivars EV x 91-2E-2, IPEAN V69 e BR8 Caldeirão. The interference of weeds throughout the life cycle of cowpea reduced the final stand, the number of pods per plant, weight of 1000 grains. The yield of genotypes EV x 91-2E-2, BR8 Caldeirão, IPEAN V69, was reduced by 59,78; 68,18 and 90.18% respectively. The period before the interference was 0 to 5 days after sowing for the cultivar BR IPEAN V69 while for the cultivars BR8 Caldeirão and EV x 91-2E-2 was 6 and 7 of, respectively.