Performance of Cowpea (Vigna unguiculata (L) Walp) as Influence by Different Weed Control Methods

Abstract

A field study was conducted during the late planting season of 2013 at the Teaching and Research Farm of the Faculty of Agriculture and Veterinary Medicine, Imo State University, Owerri, to determine the effects of different methods of weed control on the growth and yield of cowpea. Different weed control methods (Weedy Check/Control Plot (T₁WC₁), Hand-Weeding at 20 and 40 Days after planting (DAP)( T₂WC₂), Hoe Weeding at 20DAP (T₃WC₃), Chemical Weeding at 20 DAP (T₄WC₄), Hoe Weeding at 20DAP + hand – weeding at 40DAP (T₄WC_s), Chemical Weeding at 20 DAP (T₄WC₆)) were compared for their efficiency to control various weed species in Owerri, Nigeria. The experiment was laid out in a Randomized Complete Block Design (RCBD) with three replications. Cowpea seeds (Ife brown) were collected from the Department of Crop Science and Biotechnology of Imo State University, Owerri and planted at a distance of 50cm x 50cm. The post emergence herbicides (fusilade forte) used for chemical weed control was bought at Imo State Agricultural Development Programme Owerri (Imo ADP). The parameters measured were; types of weeds and their relative abundance, plant height (cm), stem girth (cm), number of branches/plant, number of leaves per plant, leaf area (cm²), number of root nodules per plant, number of days to 50% flowering, plant biomass, number of pods per plant, number of pods per plot, pods weight per plot(g), 100 seed weight(g), pod yield (kg/ha), and seed yield (kg/ha) Predominant weed types observed in the cowpea plots were; Aspilia Africana, Euphorbia heterophylla, Imperata cylindrical, Talinum triangulare , cyperus esculentus and Tridax procumbens. Among different weed control methods, hoe weeding at 20DAP + hand weeding at 40DAP gave seed yield of 47.77kg/ha. This treatment (hoe weeding at 20DAP + hand weed at 40DAP) out performed others in terms of 100 seed weight (94.10g) which significantly different (P<0.05) from the records of the other treatments. On the basis of these results, Maximum seed yield 47.77kg/ha of cowpea (Ife brown)) was obtained with the application of hoe weeding at 20DAP + hand weeding at 40DAP.

Keywords: weed biomass, herbicides, weed control, owerri, cowpea