Uso de biológicos e nutrição na mitigação de estresses em soja

Abstract

Soybean (Glycine max L.) is one of the main crops of interest in Brazil, and the country is currently the world’s largest producer and exporter of soybeans. However, in recent years, climatic instabilities such as high temperatures and water scarcity have become increasingly frequent, making it necessary to seek alternatives for a more stable and secure production under adverse conditions. Thus, this study aimed to evaluate the efficiency of the microorganisms Bacillus aryabhattay, Bacillus circulans, Bacillus haynesii and Bradyrhizobium japonicum combined with foliar fertilizers from four different companies (Brandt, Lifeagro, Fortgreen, and Compo) in mitigating these stresses. The experiment was conducted on a commercial farm belonging to the Marcante family, in Pato Branco, Paraná. The region’s climate is classified as Cfa, and the property is located at an altitude of 820 meters above sea level. The experimental design was a randomized block design with ten treatments and three replications, in a bifactorial arrangement, evaluating the efficiency of microorganisms applied in seed treatment and foliar spraying, the use of foliar fertilizers and biostimulants from four different companies, and the combined use of both technologies. A soil analysis was performed, and fertilization followed the recommended practices. Sowing took place on October 14, 2024, and harvest on February 16, 2025. Foliar applications were carried out using a manual CO-pressurized sprayer, performed at V3 (weed control), pre-closing, and 15, 30, and 45 days after pre-closing, following the fungicide applications. The analysis of variance showed a significant interaction between environment and treatment for yield. Plant height showed small differences, indicating uniformity among treatments and the absence of a marked effect of bioinputs and nutriphysiological management on vegetative growth, even under water stress. The thousand-grain weight (TGW) was slightly affected by the application of biological inoculants. In the control treatment and the nutriphysiological managements of Fortgreen and Compo, no differences were observed between the application or absence of the biological inoculant; however, there was a reduction in TGW under the Brandt and Lifeagro managements, decreasing from 211.30 g to 203.60 g and from 210.00 g to 198.97 g, respectively. Yield was the variable that most clearly demonstrated the effect of treatments, showing a significant interaction between nutriphysiological management and coinoculation. The treatment under Fortgreen management stood out with a positive response to inoculation, increasing from 91.25 to 117.77 sc ha¹, recording the highest productivity among all evaluated combinations. It is concluded that the effect of coinoculation depends on the nutriphysiological management adopted, which may result in positive, neutral, or negative responses. The selection of mana gement practices compatible with the introduced microbiota is essential to maximize soybean productivity and improve crop performance under water stress conditions.