Effects of plant density on yield parameters of cowpea (Vigna unguiculata L.)

Abstract

Cowpea (Vigna unguiculata L.) is an important pulse, fodder and green manure crop. In symbiotic association with Rhizobium bacteria, cowpea fixes atmospheric dinitrogen in its root nodules. Hence cowpea forms an integral part of the cropping systems in Indian agriculture. A field experiment was conducted during rabi 2018-19 on a sandy loam soil of Bagusala Farm (23039’ N latitude, 87o42’ E longitude), M. S. Swaminathan School of Agriculture, Gajapati District, Odisha, to study the effects of variety, plant spacing and variety x spacing interaction on the yield components of cowpea. The experiment was conducted in a split plot design with three replications. Three cowpea varieties, Ketaki, Kamini, and Gomati, were the main plots and three within row plant spacings of 10, 15 and 20 cm, corresponding to plant population densities of 333333, 222222 and 166666 plants ha-1, were the split plots, forming a total of nine treatment combinations. The seeds of cowpea were sown in rows on ridges spaced 30 cm apart. At harvest the yield attributes, pod length, pods plant-1, grain yield, 100 grain weight, biological yield, stover yield and harvest index were recorded. The three cowpea varieties tested did not differ significantly in pods plant-1 and pod length but differed in 100 grain test weight. Gomati had the highest grain test weight, followed by Ketaki, with Kamini having the least test weight. Higher grain yield was recorded in the widest spacing of 20 cm compared to the closest spacing of 10 cm. Cowpea varieties, plant spacings and variety x spacing interactions did not have significant effects on stover yields and harvest indices. The widest plant spacing of 20 cm had higher benefit-cost ratio (BC ratio) than the closer spacings of 10 and 15 cm which had similar BC ratios. Variety x spacing interactions affected BC ratio.