VIABILIDADE AGRONÔMICA DO USO DE MICRORGANISMOS SOLUBILIZADORES E DO PÓ DE ROCHA NEFELINA SIENITO COMO FONTE DE POTÁSSIO NA CULTURA DA MANDIOCA

Abstract

In the context of plant mineral nutrition, the reliance on soluble fertilizers, especially potassium fertilizers, has generated concerns related to geopolitical relations, finite reserves, price volatility, and environmental impacts. Considering this, the objective was to evaluate the agronomic efficiency of using solubilizing microorganisms and nepheline syenite rock powder as a potassium source in cassava cultivation. The study was carried out in field in the rural area of Iporá-GO, from June 2024 to June 2025. The treatments were distributed in a randomized complete block design (RCBD) with split plots, in a 3 x 8 factorial scheme, with four replications. Three potassium sources were evaluated: 100% rock dust (100% PR); 100% potassium chloride (100% KCl); and 50% rock dust + 50% KCl (50% PR + 50% KCl). And eight treatments with microorganisms: Control; Bacillus amyloliquefaciens (Amy); Bacillus aryabhattai (Ary); Cladosporium cladosporioides (Cla); and the combinations Amy + Ary, Amy + Cla, Ary + Cla, and Amy + Ary + Cla. Treatments containing nepheline syenite rock powder resulted in a greater number and weight of roots per plant, as well as higher starch and root productivity, compared to KCl fertilizer. The Amy + Ary and Amy + Cla co-inoculations contributed to increased dry matter and starch content in the roots. Nepheline syenite has shown potential to partially or completely replace KCl as a potassium source in cassava cultivation. The evaluated microorganisms contributed to improving the industrial quality of the roots.