EFFECT OF OIL PALM REFUSE BUNCH ASH ON THE GROWTH AND YIELD OF CUCUMBER (Cucumis sativus L.) VARIETIES IN HUMID ULTISOLS PEDOENVIRONMENT

Field experiment was conducted in the late growing season (August- November) of 2016 and 2017 at the experimental Farm of the Faculty of Agriculture, University of Benin, to determine the effect of oil palm refuse bunch ash (OPRBA) application on the growth and yield of three cucumber varieties. The experiment was laid out as a 3×5 split-plot arrangement fitted into a randomized complete block design and replicated three times. The main plots consisted of three cucumber varieties (Poinsett, Supermarketer and Marketer), while the sub-plots were made up of five levels (0, 2, 4, 6 and 8 t ha-1) of OPRBA. Data were collected on growth variables (vine length, vine girth, number of leaves/plant, number of branches per plant and leaf area index) at 50 % flowering day while yield components (fruit length, fruit girth, number of fruits per plant, fruit weight and fruit yield) were assessed at harvesting. The results showed that Poinsett and Supermarketer were significantly (p<0.05) higher in growth variables than Marketer. The application of the OPRBA significantly (p<0.05) enhanced the growth and yield of cucumber and fruit yield was maximized at 6 t ha-1 (15.05 t ha-1). The highest fruit yield (17.80 t ha-1) recorded by Supermarketer treated with 8 t ha-1 OPRBA but comparable to Supermarketer treated with OPRBA of 6 t ha-1 and Poinsett grown plots treated with OPRBA at 6 and 8 t ha-1. Conclusively, the application of OPRBA at 6 t ha-1and Supermarketer variety is recommended for cucumber farmers in the humid ultisols environment.