Influence of the application of humic substances on the growth of watermelon and melon seedlings

Abstract

Growing watermelon (Citrullus lanatus) and melon (Cucumis melo) is an important activity in the Brazilian Cerrado; however, many factors limit cultivation, including the difficulty of producing high-quality seedlings. In this study, the effect of humic substances (HS) on growth of ‘Crimson Sweet’ watermelon and ‘Yellow’ melon seedlings was evaluated. An experiment was carried out in a completely randomized design with five HS treatments applied to the soil: 0 (control), 5, 10, 15, and 20 g L-1. The growth of watermelon and melon seedlings was influenced by the application of humic substances. Use of HS increased plant height, stem diameter, root length, root volume, shoot dry biomass, root dry biomass, and Dickson’s quality index. HS boost plant growth, whose improved root system may have provided greater absorption and accumulation of mineral nutrients. Based on the quality of the seedlings (Dickson index), the application of 14 g L-1 of HS is recommended for watermelon seedling production and 15 g L-1 of HS for melon seedling production.