Humic substances extracted from organic compounds and their influence on the morphophysiological characteristics of tomato seedlings

Abstract

The tomato seedling is one of the main inputs in the production process, and its quality is a strategic factor, making agriculture more competitive. It is possible to produce seedlings of exceptional quality using humic substances extracted from organic compounds, through the composting process. The humic acids present in humic substances play an important role in the release of nutrients, such as N, P, K, improvement of the chemical properties of the soil, elevation of the root system. In this scope, the disposal of organic waste for the composting process can be an economically sustainable alternative. From this, the objective of the research was to test the production of tomato seedlings through the application of humic acids and fulvic acids from the process of composting organic waste. The study was carried out at the State University of Bahia - UNEB, in Euclides da Cunha - BA, using a commercial cultivar. The materials used in the composting process were: coconut fiber, quixabeira soil, cattle manure and humus. Morphophysiological characteristics such as seedling height, stem diameter, chlorophyll content, root length, root volume, fresh and dry mass of tomato roots were evaluated in a completely randomized design with 3 compounds and 5 doses, totaling 15 treatments and 5 repetitions for each compound dose, with a 3x5 factorial scheme. The doses used were 0.0; 0.5; 1.0; 2.0 and 4.0 mL plant-1. Based on the main results, it was possible to conclude that the dose of 0.5 mL plant-1 allowed greater root volume (0.70 cm³), root fresh mass (0.46 g), root dry mass (0.27 g), root length (15.2 cm), seedling height (18.4 cm), stem diameter (0.50 mm), and chlorophyll content (44.5 ug cm-2), in relation to other doses, being, therefore, recommended for root growth of tomato seedlings in semi-arid conditions.