EFFECT OF FOLIAR APPLICATION OF RED LARGE ONION (Allium cepa L.) PEEL SOLUTION ON GROWTH AND YIELD OF COWPEA (Vigna unguiculata L. WALP)

Abstract

Cowpea (Vigna unguiculata L. Walp.) is a significant food and grain legume in the semi-arid tropic. Red onion peels are utilized to produce organic potassium rich fertilizer for the cultivation of crops. Hence, this experiment was carried out to study the effect of red large onion (Allium cepa L.) peel solution as a foliar application on the growth and yield of cowpea. It was designed in a randomized complete block design with six treatments (20, 40, 60, 80 and 100% onion peel solution and control with water). In this experiment, the red large onion peels (100 g) from kitchen waste were added to one litre of water and then kept at room temperature for 48 hours. Thereafter, the liquid solution was filtered using a 1 mm-sized mesh sieve and filtered solution was considered as 100% onion peel solution. The treatments were applied at two weeks intervals starting from two weeks after planting seeds The results revealed that foliar application of onion peel solutions led to significant (P<0.05) effects on tested parameters over the control. The application of 40% concentration onion peel solution increased the plant height, number of leaves and number of branches per plant, at 9th week after planting and also number of nodules was recorded after harvesting pods. Among the treatments, the application of 100% concentration onion peel solution gave the highest values in many measured yield parameters. There were no significant differences in these parameters between plants applied with 80% and 100% onion peel solutions. Further, significantly (P<0.05) highest yield was obtained in plants treated with 100% onion peel solution (403.64 g/m2 ) followed by 80% solution application (342.17 g/m2 ) compared to the control treatment (112.41 g/m2 ). Therefore, it could conclude that 80% - 100% concentrations of onion peel solution could be used to enhance the seed yield of Vigna ungiculata L.