Agronomic performance of cowpea, cv. Rouxinol, in function of row spacings and plant densities under dry condition.

Abstract

An experiment was carried out on Yellow Angissoil Soilin Teresina, Piauí, Brazil during the dry season of the agricultural year of 2002/2003. The prupose of the work was to evaluate the productivity behavior of cowpea (Vigna unguiculata (L.) Walp.), under different array spacings and plant densities. Experimental data were analyzed as a complete randomized block in a factorial scheme (3 x 4), with four replications. The row spacing were 50; 70 cm and 90 cm associated to four different densities (4; 8; 12 and 16 plants.m^-2). The row spacings x plant density interaction was not significant, evidencing that the spacing effect was independent of the plant density effect and vice versa. The grain yield and production per plant were influenced by spacing, being observed a linear decreasing with the increasing of the plant spacing. The pod number and the grains production per plant presented a linear decreasing when the plant density increased, occurring a quadratic effect on the grain yield. The maximum grain yield, 1,670 kg.ha^-1, was obtained with 7.75 plants.m^-2.