Efeito da simbiose micorrízica e bactérias associativas no teor de nitrogênio e produtividade do milho e produtividade da mandioca no trópico úmido

Abstract

Nature-based solutions have emerged as sustainable strategies to increase agricultural productivity, reduce the use of chemical inputs, and improve soil health. In this context, this study aimed to compare the use of biological inputs—such as diazotrophic bacteria and arbuscular mycorrhizal fungi (AMF), applied either individually or in combination—against conventional chemical fertilization, evaluating their effects on the performance of maize and cassava crops. The experiment was conducted under no-till conditions in sandy-loam soil in a tropical climate, using a randomized complete block design with five treatments and four replicates. The treatments included a negative control, an NPK-fertilized control, inoculation with *Azospirillum brasilense*, inoculation with the AMF species *Rhizoglomus clarum*, and a combination of both. The soil also received green manure (*Crotalaria juncea*) as well as amendments with lime and reactive natural phosphate. For the maize crop, only the hundred-grain mass showed a statistically significant difference—with the AMF treatments and the control without NPK standing out—suggesting a contribution from the native microbiota and the efficiency of the microorganisms in nutrient uptake. The other productive and nutritional variables showed no relevant differences among treatments. In the cassava crop, significant differences were observed in total productivity and commercial root yield; the best results were obtained with the biological treatments, particularly the combination of bacteria and fungi. This indicates that the inoculants contributed to root development and nutrient utilization. The results show that the use of bio-inputs is a promising alternative to conventional chemical fertilization, fostering agronomic and environmental gains, especially in family farming systems seeking greater sustainability in soil management