Growth components and chemical composition of some improved dual-purpose cowpea (<i>Vigna unguiculata</i> L. Walp) varieties as influenced by manure application

Abstract

Field experiment was conducted to determine the effect of swine manure application on the growth components and chemical composition of nine varieties of improved dual-purpose cowpea (Vigna unguiculata L. Walp). The experiment was laid out as a 2 x 9 factorial design with two levels of manure application (0kg ha^-1 and 5kg ha^-1) and nine varieties of improved dual-purpose cowpea at three replicates. Agronomy parameters and dry matter yield of the cowpea were determined six weeks after sowing. Results showed that unfertilized variety IT- 332 recorded highest leaf proportion (57.27) above others. Varieties IT-193 with manure (80.00 cm) and IT-297 without manure (30) recorded significantly higher (P<0.05) values for plant height and leaf number respectively. Dry matter yield of cowpea ranged significantly higher (P<0.05) from 7.20 t ha^-1 in variety IT-817 without manure to 14.85 t ha^-1 in variety IT-321 with manure. The average crude protein content of improved cowpea varieties ranged significantly (P < 0.05) from 97.69 g kg^-1 dry matter in unfertilized IT-817 and IT-834 to 141.17 g kg^-1 dry matter in fertilized IT-819. The study showed that application of swine manure into cowpea increased the dry matter yield and chemical composition which is necessary to provide sufficient feed for ruminants that can be used as a supplement during the dry season.

Keywords: Dry matter yield, cowpea varieties, nutrient contents, swine manure