Watermelon (Citrullus lanatus Thunb.) Production as Affected by Soil Potassium Fertilizer and Livestock Manure

Abstract

Organic-mineral nutrient availability in soils cultivated with vegetables is essential for a satisfactory and economically viable production, including the watermelon (Citrullus lanatus). The aim of this experiment was to evaluate the influence of the addition of livestock manure to the soil with and without potassium on watermelon (cv. Crimson Sweet) production in Paraiba, Brazil. The treatments were arranged in a design of randomized blocks, with four replications, with a factorial arrangement 2 × 5 + 1, in relation to the absence and presence of potassium, five levels of livestock manure (0, 360; 1.080; 1800 and 2510 g hole^-1) in the soil with nitrogen fertilization, and a control treatment (without cattle manure or mineral fertilizers). The number of fruits per plant, the average weight of the fruits per plant, and the yield were evaluated. The plants responded positively to the application of livestock manure to the soil, but the results were higher in combination with potassium fertilization. Productivity increased in treatments in which potassium was supplied to the soil in addition to a maximum of 1124 g hole^-1 of cattle manure. Half of the previously recommended level of potassium supply was enough to raise the productivity of watermelon in the region.