EFEITO DE MICRORGANISMOS PROMOTORES DE CRESCIMENTO NO SISTEMA RADICULAR DA SOJA: Análise do desenvolvimento radicular em fase inicial

Abstract

Soybeans are a fundamental crop for the global supply of grains, oils, and proteins. The use of plant growth-promoting microorganisms is consolidated as a sustainable alternative to increase productivity and reduce dependence on chemical fertilizers.This study aimed to analyze the effects of individual and combined inoculations of growth-promoting microorganisms on the initial root development of soybeans. The experiment was carried out in a greenhouse at Embrapa Rice and Beans, in Santo Antônio de Goiás, Goiás, Brazil, in a completely randomized design, with five treatments: control (without inoculation), inoculation with Serratia marcescens, Bacillus sp., Azospirillum brasilense, and Trichoderma koningiopsis, in addition to coinoculation between the microorganisms, totaling ten replicates per treatment. The seeds were microbiolized and cultivated for 14 days in a substrate composed of soil and sand, without the addition of fertilizers, under daily irrigation to maintain moisture. The results indicated significant effects (p ≤ 0.01) on root development. The treatment with Azospirillum brasilense increased the total length of the roots by 29%, increasing from 38.73 cm in the control to 50.07 cm. In turn, Trichoderma koningiopsis and coinoculation provided increases in diameter (up to 1.67 mm) and root volume (up to 1.24 cm³), effects associated with the production of phytohormones and nutrient solubilization. On the other hand, Serratia marcescens reduced the root surface area by approximately 31%.