Evaluation of watermelon response to population densities and cow dung manure in an ultisols

Abstract

Field experiments were conducted in 2016 to evaluate the effects of different population densities and cow dung manure application rates on growth, yield and nutritional quality of watermelon in an Ultisol, Nigeria. The plant population densities were 15,625, 12,346, 10,000 and 8,264 plants ha⁻¹ while the cow dung rates comprised 10, 7.5, 5 and 2.5 t ha^-1. The treatments were arranged in a randomized complete block design. Results show that vine length, number of leaves on main stem, number of lateral branches and main vine diameter were significantly (P<0.05) affected by the different plant population densities and were higher in plots with lower population densities compare to plots with higher population densities. Numbers of primary lateral branches were higher in plots with higher population densities than plots with lower population densities. Vine length increase with increase rate of cow dung manure and plots with highest rate of cow dung manure recorded the highest vine length in both locations. Carbohydrate and dietary fiber increased with increased rate of cow dung manure up to when cow dung rate was 7.5t ha^-1. Number of fruits per plant and average fruit weight decreases with increase in plant population densities. Number of fruits per plot, and weight of fruit per plot were significantly affected by cow dung rate. There were no significant differences in number of fruits per plot, average weight of fruits and weight of fruit per plot when cow dung was applied at 5.0, 7.5 and 10t ha^-1. Cow dung application rate of 5 t ha^-1 and a plant population of 10,000 plants ha^-1 is therefore recommended for watermelon growers in an ultisol.