Ácido húmico como indutor de crescimento de mudas de batata-doce Brazlândia Branca

The objective of this study was to evaluate the growth of sweet potato seedlings from mini cuttings with the application of different concentrations of humic acid. The experimental design was completely randomized, with five concentrations of humic acid (0, 5, 10, 15, 20 and 25 ml L-1) and six replicates. The treatments were applied in tropstrato substrate contained in the cells of trays in the amount of 20 ml per plant diluted in water. It was determined the content of chlorophyll a, b and total number of leaves, root number, fresh weight of aerial part, the root fresh weight and dry weight of shoots and roots. Humic acid had no influence on the chlorophyll content and aerial part of the seedlings, showing a positive influence on the root system with increment in root numbers, root length and root dry matter.