Use of Synchrotron tomography as strategy to elucidate N2O production pathways in tropical soils

• Grant number: 22/16763-2
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: April 01, 2023
• End date: March 31, 2024
• Field of knowledge: Agronomical Sciences - Agronomy - Soil Science
• Agreement: BG E&P Brasil (Shell Group)
• Principal Investigator: Carlos Eduardo Pellegrino Cerri
• Grantee: Thaís Nascimento Pessoa
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
• Company: Universidade de São Paulo (USP). Escola Politécnica (EP)
• Associated research grant: 20/15230-5 - Research Centre for Greenhouse Gas Innovation - RCG2I, AP.PCPE

Abstract

N2O emissions play a fundamental role in the process of mitigating climate change. Understanding the mechanisms that regulate N2O emissions from agricultural soils is crucial for establishing effective mitigation strategies. N2O is a potent greenhouse gas, produced mainly by the addition of nitrogen sources (synthetic and organic. Several factors, such as the addition of nitrogen and carbon, soil microbiota, soil porosity and oxygenation level, define the production of N2O through the nitrification and denitrification pathways. The adoption of integrated crop-livestock (ICL) systems represents the strategic incorporation of a forage crop (mainly Brachiaria) in traditional agricultural systems. Recent studies have observed that Brachiaria has an extensive root system and increases soil porosity through the formation of biopores. Based on these statements, we hypothesized that the adoption of ICL systems increases the pore network and improves soil physico-hydric conditions, and consequently modifies the main N2O production pathway. The objective of this project is to elucidate the mechanisms of N2O production in areas under ICL system and conventional agriculture. For that, the following specific aims were established: i) quantify N2O emissions from soil in a controlled environment; ii) decipher how soil pore network characteristics (total porosity, pore size distribution, connectivity, and tortuosity) and the soil physico-hydric conditions govern N2O emissions using synchrotron tomography techniques; iii) identify correlations between N2O emissions and pore network characteristics. For the conduction, incubation experiments will be carried out in a controlled environment and the evaluation of the characteristics of the pore network will be carried out by X-ray computed microtomography at Mogno beanline (Sirius). Additionally, the results of this research will be integrated with other project activities, such as activities of molecular biology and nitrogen isotopes techniques, to elucidate the main routes of N2O production in tropical soils under agricultural cultivation. (AU)