Changes in carbon stock and greenhouse gas balance in a coffee (Coffea arabica) monoculture versus an agroforestry system with Inga densiflora, in Costa Rica

Hergoualc'h, Kristell; Blanchart, Eric; Skiba, Ute ORCID: https://orcid.org/0000-0001-8659-6092; Henault, Catherine; Harmand, Jean-Michel. 2012 Changes in carbon stock and greenhouse gas balance in a coffee (Coffea arabica) monoculture versus an agroforestry system with Inga densiflora, in Costa Rica. Agriculture, Ecosystems and Environment, 148. 102-110. 10.1016/j.agee.2011.11.018

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Official URL: http://dx.doi.org/10.1016/j.agee.2011.11.018

Abstract/Summary

Agroforestry represents an opportunity to reduce CO2 concentrations in the atmosphere by increasing carbon (C) stocks in agricultural lands. Agroforestry practices may also promote mineral N fertilization and the use of N-2-fixing legumes that favor the emission of non-CO2 greenhouse gases (GHG) (N2O and CH4). The present study evaluates the net GHG balance in two adjacent coffee plantations, both highly fertilized (250 kg N ha(-1) year(-1)): a monoculture (CM) and a culture shaded by the N-2-fixing legume tree species Inga densiflora (CIn). C stocks, soil N2O emissions and CH4 uptakes were measured during the first cycle of both plantations. During a 3-year period (6-9 years after the establishment of the systems), soil C in the upper 10 cm remained constant in the CIn plantation (+0.09 +/- 0.58 Mg C ha(-1) year(-1)) and decreased slightly but not significantly in the CM plantation (-0.43 +/- 0.53 Mg C ha(-1) year(-1)). Above-ground carbon stocks in the coffee monoculture and the agroforestry system amounted to 9.8 +/- 0.4 and 25.2 +/- 0.6 Mg C ha(-1), respectively, at 7 years after establishment. C storage rate in the phytomass was more than twice as large in the CIn compared to the CM system (4.6 +/- 0.1 and 2.0 +/- 0.1 Mg C ha(-1) year(-1), respectively). Annual soil N2O emissions were 1.3 times larger in the CIn than in the CM plantation (5.8 +/- 0.5 and 4.3 +/- 0.3 kg N-N2O ha(-1) year(-1), respectively). The net GHG balance at the soil scale calculated from the changes in soil C stocks and N2O emissions, expressed in CO2 equivalent, was negative in both coffee plantations indicating that the soil was a net source of GHG. Nevertheless this balance was in favor of the agroforestry system. The net GHG balance at the plantation scale, which includes additionally C storage in the phytomass, was positive and about 4 times larger in the CIn (14.59 +/- 2.20 Mg CO2 eq ha(-1) year(-1)) than in the CM plantation (3.83 +/- 1.98 Mg CO2 eq ha(-1) year(-1)). Thus converting the coffee monoculture to the coffee agroforestry plantation shaded by the N-2-fixing tree species I. densiflora would increase net atmospheric GHG removals by 10.76 +/- 2.96 Mg CO2 eq ha(-1) year(-1) during the first cycle of 8-9 years. (c) 2011 Elsevier B.V. All rights reserved.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1016/j.agee.2011.11.018
Programmes:	CEH Topics & Objectives 2009 - 2012 > Biogeochemistry
UKCEH and CEH Sections/Science Areas:	Billett (to November 2013)
ISSN:	0167-8809
Additional Keywords:	Funders: EU CASCA project
NORA Subject Terms:	Ecology and Environment
Date made live:	15 Apr 2013 13:58 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/501063

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1016/j.agee.2011.11.018

Programmes:

CEH Topics & Objectives 2009 - 2012 > Biogeochemistry

UKCEH and CEH Sections/Science Areas:

Billett (to November 2013)

ISSN:

0167-8809

Additional Keywords:

Funders: EU CASCA project