LASTING EFFECT OF LIME AND PHOSPHOGYPSUM APPLICATION IN NO-TILLAGE: INTERACTION BETWEEN SOIL FERTILITY AND THE EFFECTIVENESS OF Rhizobium tropici INOCULATION IN COMMON BEAN

• Grant number: 24/15134-7
• Support Opportunities: Scholarships in Brazil - Master
• Start date: July 01, 2025
• End date: July 31, 2026
• Field of knowledge: Agronomical Sciences - Agronomy - Crop Science
• Principal Investigator: Carlos Alexandre Costa Crusciol
• Grantee: Bruno Moço Tessarolli
• Host Institution: Faculdade de Ciências Agronômicas (FCA). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil

Abstract

Acid soils are responsible for poor nutrient assimilation and low efficiency of biological nitrogen fixation (BNF), which is promoted by symbiotic associations between Rhizobium bacteria and plant roots, significantly impacting the productivity of common bean (Phaseolus vulgaris L.). In this context, liming is an essential tool for maintaining agricultural production. However, in agricultural systems managed under no-tillage systems, the low mobility of lime reduces its effectiveness. Therefore, strategies such as the use of agricultural phosphogypsum become crucial for enabling surface liming. This research proposal continues a long-term experiment established in 2002/03 at the Lageado Experimental Farm, at the School of Agriculture at UNESP, in Botucatu (SP). The objective is to understand, for the first time, how the development of soil fertility promoted by long-term surface application of lime and/or phosphogypsum in no-tillage affects the effectiveness of inoculation with Rhizobium tropici in common bean plants, and its effects on nutritional, physiological, and productive status of the crop. The experimental design will be a randomized block design with inoculated and non-inoculated plots with Rhizobium tropici, with four replications each. The treatments are: i) no application of lime and/or phosphogypsum; ii) phosphogypsum application; iii) lime application (recommended dose to raise base saturation to 70%); iv) lime + phosphogypsum application. During the experiment, evaluations of the nutritional status of the common beans, gas exchange measurements, determination of photosynthetic pigments, nodulation, root growth in the 0-20 cm layer, and microbiological soil analysis will be conducted. After harvest, production components and productivity will also be assessed. (AU)