EFFECT OF APPLICATION OF Si AND Mg ASSOCIATED WITH INOCULATION OF Bacillus aryabhattai AS PLANT NUTRITION, PHYSIOLOGY AND FOLIAR ANATOMY IN SOYBEAN IN THE BRAZILIAN SAVANNAH

• Grant number: 24/05873-7
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: August 01, 2025
• End date: November 30, 2026
• Field of knowledge: Agronomical Sciences - Agronomy - Soil Science
• Principal Investigator: Marcelo Andreotti
• Grantee: Vitória Almeida Moreira Girardi
• Host Institution: Faculdade de Engenharia (FEIS). Universidade Estadual Paulista (UNESP). Campus de Ilha Solteira. Ilha Solteira , SP, Brazil

Abstract

Soybean cultivation and productivity, like that of other crops, have been affected by the major impact of climate change, altering the stability of agricultural systems, mainly due to major changes in temperatures and reduced water availability. In this context, one of the sustainable alternatives is the use of Plant Growth Promoting Bacteria (PGPBs) such as Bacillus aryabhattai, which can provide a sustainable form of production, being one of the strategies to improve plant resistance to adverse conditions, in particular to environmental stresses resulting from climate change. This study seeks to fill this gap by evaluating the synergistic potential of these strategies and their impacts on soybean physiology and yield. In view of the above, this study aims to evaluate the response of soybean to the effect of foliar application of Si and Mg (even in soils with medium to high content of these elements), individually and in combination with the coinoculation of B. aryabhattai, evaluating a possible synergism between these elements, thus enabling a stimulus in photosynthetic physiology, leaf anatomy, as well as in plant nutrition and crop productivity. The experiment will be developed in two agricultural years, in the same experimental area, belonging to the Faculty of Engineering - UNESP, located in Selvíria - MS, Brazil. The experimental design will be in randomized blocks, with four replications, arranged in a triple factorial scheme 2 x 2 x 2, totaling 32 plots. The first factor will consist of inoculation with Bradyrhizobium japonicum (control) and the coinoculation of B. japonicum and B. aryabhattai. The second factor will consist of the supply of Mg and/or Si via foliar application. As a cover crop preceding soybeans, a consortium of black oats (EMBRAPA 29) + forage radish will be used in the fall/winter in a No-Tillage System (SPD), to form straw for soil cover in which soybeans will be sown later. Soybeans (cultivar adapted to the region) will be sown in November of both harvests (2024/25 and 2025/26), under the straw of the black oats + forage radish consortium and all seeds will be inoculated with Bradyrhizobium japonicum and in the co-inoculation via seeds, B. aryabhattai strain CCT 8087 will be used, while foliar fertilizers (Mg and/or Si) will be applied when the plants are in phenological stage between V4 to V6. Assessments will be carried out to measure the net photosynthesis rate, water use efficiency, stress-related enzymatic activity, quantification of the number and mass of nodules, anatomy of the wall thickness and leaf cuticle, nutritional analysis of the third trifoliate at phenological stage R1, morphological components and grain production and productivity at harvest.