The 20-year legacy of soil fertility management with lime and phosphogypsum: activity and persistence of biological nitrogen fixation

• Grant number: 22/14396-2
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: August 01, 2023
• End date: July 31, 2026
• Field of knowledge: Agronomical Sciences - Agronomy - Soil Science
• Principal Investigator: Carlos Alexandre Costa Crusciol
• Grantee: João William Bossolani
• Host Institution: Faculdade de Ciências Agronômicas (FCA). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil

Abstract

This research project continues a long-term experiment, started in 2002 at Fazenda Experimental Lageado, belonging to College of Agricultural Sciences (FCA/UNESP, Botucatu-SP). As the only field experiment of its kind in the State of São Paulo with 20 years of evaluation, the present proposal aims to unravel how the soil physical and chemical properties after the long-term surface application of lime and phosphogypsum may affect the persistence of Bradyrhizobium sp. during soybean season, as well the efficiency of biological nitrogen fixation (BNF) and soybean physiological and productive responses. The field part of this proposal has been carried out since October 2016, when the following treatments were applied for the last time: i) control, ii) phosphogypsum (10 t ha1), iii) liming (13 t ha1), and iv) combination of lime and phosphogypsum. The sowing of the soybean crop from this proposal will take place in October 2023 and 2024. Soil samplings (for physicochemical and microbiological analysis) will be carried out between October 2023 and December 2024. The methodology to be used in this project is well comprehensive and makes use of complementary strategies. For this, data from the soil physicochemical attributes will be integrated with the techniques of quantitative real-time PCR (qPCR) and high-throughput sequencing of soil genomic DNA (16S rRNA and nifH), nodulation and efficiency of biological fixation of nitrogen, as well as the physiological and productive profile of soybean plants cultivated in these different treatments. All the data obtained will be analyzed and integrated through statistical modeling, trying to discover which are the main soil factors responsible for changes in the microbial community, in the efficiency and survival of nitrogen-fixing microorganisms, in addition to seeking to understand how the physiology and productive responses of soy may be related to these factors.