CH4 and N2O fluxes from planted forests and native Cerrado ecosystems in Brazil

Alexsandra Duarte De Oliveira,Diana Regazzi Zuim,Fabiana Piontekowski Ribeiro,João Paulo Guimarães Soares,Alcides Gatto,Eloisa Aparecida Belleza Ferreira,Juaci Vitoria Malaquias,Karina Pulrolnik,Arminda Moreira De Carvalho,Luciano De Almeida Pinheiro

doi:10.1590/1678-992x-2018-0355

Alexsandra Duarte De Oliveira, Diana Regazzi Zuim + Show 8 more

Open Access

https://doi.org/10.1590/1678-992x-2018-0355

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Abstract

Forest soils are N2O sources and commonly act as CH4 sinks. This study evaluated the dynamics of the CH4 and N2O fluxes of soils under Eucalyptus plantations and native Cerrado vegetation, as well as possible interactions between environmental factors and fluxes. The study was carried out in the Distrito Federal, Brazil, during 26 months, in three areas: in two stands of the hybrid Eucalyptus urophylla × Eucalyptus grandis, planted in 2011 (E1), and in 2009 (E2) and native Cerrado vegetation (CE). Measurements to determine the fluxes in a closed static chamber were carried out from Oct 2013 to Nov 2015. Soil and climate factors were monitored. During the study period, the mean CH4 fluxes were –22.48, –8.38 and –1.31 μg CH4 m–2 h–1 and the mean N2O fluxes 5.45, 4.85 and 3.85 μg N2O m–2 h–1 from E1, E2 and CE, respectively. Seasonality affected plantations in the studied sites. Cumulative CH4 influxes were calculated (year-1: –1.86 to -0.63 kg ha–1 yr–1; year-2: –1.85 to –1.34 kg ha–1 yr–1). Cumulative N2O fluxes in the three sites were ≤ 0.85 kg ha–1 yr–1. The change in land use from Cerrado to Eucalyptus plantations did not significantly changed regarding greenhouse gases (GHG), compared to the native vegetation. Flux rates of both gases (N2O and CH4) were low. Temporal variations in GHG fluxes and different ages of the stands did not cause significant differences in cumulative annual fluxes.

Highlights

Changes in land use have led tropical soils to estimated emissions of 0.2 Gt C yr–1, accounting for 10-30 % of total C emissions from deforestation (Houghton, 1999; Achard et al, 2004)
This study evaluated the dynamics of the CH4 and N2O fluxes of soils under Eucalyptus plantations and native Cerrado vegetation, as well as possible interactions between environmental factors and fluxes
The mean annual N2O fluxes were 4, 8, and 3 μg m–2 h–1 for year-1 and 5, 5, and 4 μg m–2 h–1 for year-2 in E1, E2, and Cerrado vegetation (CE), respectively (Figure 3B)

Summary

Introduction

Changes in land use have led tropical soils to estimated emissions of 0.2 Gt C yr–1, accounting for 10-30 % of total C emissions from deforestation (Houghton, 1999; Achard et al, 2004). In the context of a low-carbon economy, forest stands can be an option to reduce pressure on the native vegetation and mitigate the effects of climate change (Bonan, 2008). Land-use changes alter chemical, physical, and biological properties of the soil, modifying the GHG fluxes (Kim and Kirschbaum, 2015). Long-term N inputs may favor soil C stocks, mainly in litter with a high lignin content (Grandy and Neff, 2008). Microbial communities can be altered by climate warming, N fertilization, pH and the C:N ratio (Högberg et al, 2007; Lucas et al, 2007). Metabolic responses of the microbial community to N enrichment are complex and highly variable (Michel and Matzner, 2003)

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