HUMIC SUBSTANCES IN THE TREATMENT OF RICE SEEDS ALTER THE SEEDLING VIGOR AND MORPHOPHYSIOLOGY

Abstract

The use of humic substances can induce physiological responses that increase the production of agricultural crops. However, few studies address its use in seed treatment, and when associated with rice cultivation are almost non-existent. Thus, the objective was to evaluate the responses of the application of humic substances in the treatment of seeds on vigor, morphology, biomass accumulation and in the physiology of rice seedlings, cultivate IRGA 431. The study was conducted with four doses of humic substances (0, 50, 100 e 150 mL 100 kg^-1 of seeds) applied in the treatment of seeds, arranged in a completely randomized design, with four replications and 40 seeds each. The humic substances were extracted from ruminal compound with KOH and applied directly to the seeds. The crop was cultivated up to stage V3 and variables on germination, morphology, biomass and physiology measured and evaluated by analysis of variance (p≤0.05) with models adjusted by polynomian regressions. There was a positive response, mainly, about the emergence speed index, root volume, shoot biomass and CO₂ assimilation rate in the order of 10, 13, 53 and 73%, respectively. These results show that humic substances associated with seed treatment potentiate the initial development of rice culture.