Linking physicochemical soil factors and denitrifying microbial genes to nitrous oxide fluxes in afforested areas affected with Eucalyptus and Citrus in southeastern Brazil

• Grant number: 17/17441-0
• Support type: Scholarships abroad - Research Internship - Master's degree
• Effective date (Start): October 09, 2017
• Effective date (End): December 08, 2017
• Field of knowledge: Agronomical Sciences - Agronomy - Soil Science
• Principal researcher: Acacio Aparecido Navarrete
• Grantee: Caroline Sayuri Nishisaka
• Supervisor abroad: Laura Meredith
• Home Institution: Centro de Ciências e Tecnologias para a Sustentabilidade (CCTS). Universidade Federal de São Carlos (UFSCAR). Sorocaba , SP, Brazil
• Research place: University of Arizona, United States
• Associated to the scholarship: 16/15289-4 - Impacts of land-use change and crop residues on nitrous oxide emission and abundance of soil denitrifiers bacteria, BP.MS

Abstract

We present here a research internship abroad plan which main objective is to address directly and reliably on of principal research proposal's two core aims (FAPESP 2016/15289-4), which focuses on the application of computational approaches to combine the different datasets (physical and chemical soil factors, N2O emission fluxes and functional gene abundance - nirK/S and nosZ) for both field and microcosm experiments. Based on these analyses, the follow relations will be interpreted: i) the relation between physical and chemical characteristics on N2O emission from soil. For this purpose, soil texture, total carbon and nitrogen, dissolved organic carbon, and N2O emission fluxes from soil under Citrus, Eucalyptus and adjacent native vegetation (data already obtained) will be related using classical statistical methods including pairwise comparisons, correlations, and multivariate analysis using packages in the R programming language; (ii) the relation between denitrifier microbial community in Eucalyptus- and Citrus-cultivated soils and adjacent sites of native vegetation and chemical characteristics of soil and plant residues on surface soil (data already obtained). The functional microbial genes nirK/S e nosZ copy number in soil under the different land-use will be related to total carbon and nitrogen, dissolved organic carbon, and N2O emission fluxes from soil using similar statistical tools as mentioned in (i). This analysis will be used to develop hypotheses regarding the role of denitrifier microbial communities in driving N2O fluxes. In addition, we will analyze the correspondence between nirK/S e nosZ copy number (qPCR) and microbial community composition (phylogenetic amplicon sequencing) in high- and low-N2O emission regions of the B2 Tropical Rainforest, a research project ongoing at University of Arizona. Microbial community data has already been obtained, and we will use tools to identify differentially abundant taxa (denitrifying and others) at sites with high and low N2O emissions. Our aim is to identify the diversity of taxa that drive observed differences in both functional gene copy number and N2O emissions, which may aid in the interpretation and modeling of qPCR data from the Eucalyptus- and Citrus-cultivated soils. The expected results of this research internship abroad will allow a more detailed understanding about the impacts of forest-to-agriculture conversion on soil chemical and microbiological properties associated with the denitrification process.

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

NISHISAKA, CAROLINE SAYURI; YOUNGERMAN, CONNOR; MEREDITH, LAURA K.; DO CARMO, JANAINA BRAGA; NAVARRETE, ACACIO APARECIDO. Differences in N2O Fluxes and Denitrification Gene Abundance in the Wet and Dry Seasons Through Soil and Plant Residue Characteristics of Tropical Tree Crops. FRONTIERS IN ENVIRONMENTAL SCIENCE, v. 7, FEB 5 2019. Web of Science Citations: 1.