Paddy husk ash as a source of potassium for growth and yield of cowpea ( Vigna unguiculata L.)

Abstract

An experiment was conducted to study the effect of paddy husk ash as a source of potassium on growth and yield of cowpea (Vigna unguiculata L.). The treatments included recommended rate (0.075 ton/ha) of muriate of potash as a control (T 1) and application of paddy husk ash at the rate of 1.5 (T 2), 2.5 (T 3), 3.5 (T 4) and 4.5 (T 5) tons/ha. This experiment was laid out in a Randomized Complete Block Design with four replications in sandy regosol. The agronomic parameters were recorded at regular intervals. Result revealed that there were no significant differences among treatments especially for number of seeds and dry weights of leaves, stem and root. However, number of nodules, number of pods, dry weight of pod and 100 seed weight were significantly varied among treatments. It was further noted that application of paddy husk ash at the rate of 4.5 tons/ha gave high yield (1.44 tons/ha) followed by T 1 (1.42 tons/ha) and T 4 (1.35 tons/ha). The application of paddy husk ash at the rate of 4.5 tons/ha is suitable for obtaining high yield of cowpea in sandy regosol. Hence paddy husk ash could be used as a source of potassium in cowpea cultivation due to the potential constraint of chemical fertilizer and the benefits of organic farming in Sri Lanka.