Soil CO2 Efflux Measurements by Alkali Absorption and Infrared Gas Analyzer in the Brazilian Semiarid Region

Carlas Renata Prissila Costa Ferreira,Willames De Albuquerque Soares,Everardo Valadares De Sá Barreto Sampaio,José Romualdo De Sousa Lima,Antonio Celso Dantas Antonino,Rômulo Simões Cezar Menezes,Karina Guedes Correia

doi:10.1590/18069657rbcs20160563

Abstract

ABSTRACT The CO2 emission from the soil surface, commonly referred to as soil CO2 efflux (ECO2) or soil respiration, is the sum of processes that include root respiration and microbial activity. Measuring this evolution is important to establish sustainable land use models and to estimate global fluxes of carbon, which affect climate change. Despite its importance, few measurements have been made in areas of the semiarid Brazilian Northeast region, and most of them were made using the alkali absorption method [...]

Highlights

The carbon cycle has received increased attention due to escalating concentrations of atmospheric carbon gas and its relationship with global warming and climatic changes (IPCC, 2014)
Measurements using alkali absorption method (AA) were compared to measurements using the infrared gas analyzer method (IRGA) over ten months, during the day and night, in areas of Caatinga and pasture in the Agreste region of the state of Pernambuco
The Caatinga soil had a higher total organic carbon (TOC) content than the pasture soil (Table 1). Both contents were within the range usually found in sandy soils of semiarid regions (Santos et al, 2012; Medeiros et al, 2015) and the higher Caatinga TOC was not enough to cause a different pore size distribution compared to that from pasture soil

Summary

Introduction

The carbon cycle has received increased attention due to escalating concentrations of atmospheric carbon gas and its relationship with global warming and climatic changes (IPCC, 2014). Several studies have quantified ECO2 in specific areas in Brazil (Valentini et al, 2008; Panosso et al, 2009; Souto et al, 2009; Araujo et al, 2011; Ivo and Salcedo, 2012; Correia et al, 2015; Holanda et al, 2015) and in other countries (Deng et al, 2012; Chen et al, 2014; Zheng et al, 2014) These studies used different methodologies to quantify ECO2, the most common ones being CO2 absorption in an alkaline solution (AA), in general 0.5 or 1.0 mol L-1 KOH or NaOH (Souto et al, 2009; Araujo et al, 2011; Correia et al, 2015). These methodologies differ in precision, applicability, and spatial and temporal resolution (Janssens et al, 2000; Yim et al, 2002)

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