A framework coupling farm typology and biophysical modelling to assess the impact of vegetable crop-based systems on soil carbon stocks. Application in the Caribbean

J. Sierra, F. Causeret, P. Chopin

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

© 2017 Elsevier LtdAgricultural land devoted to vegetable crops in the Caribbean has strongly increased during the past twenty years, which raises major concerns regarding a reduction in soil organic carbon (SOC) stocks because of low C inputs and high SOC outputs from these cropping systems. The aim of this study was to assess the impact of farming practices on SOC stocks at the farm type level. We designed a framework which encompasses a farm typology describing the diversity of farm practices applied to vegetable crops and a model of SOC dynamics to estimate the impact of these practices on SOC stocks. The study was carried out in the Guadeloupe archipelago, which offers a good representation of the variability of Caribbean agriculture, in a context of transition from traditional sugarcane and banana monocultures for export to a more diversified agriculture including vegetable crops. A farm typology was developed from a survey of 71 farmers concerning their socio-economic characteristics and farming practices. The MorGwanik model of SOC dynamics was then used to assess the impact of farming practices on SOC at the farm type level, and to interpret the observed SOC changes. Five farm types were identified varying from traditional export agriculture with low diversification to monoculture of vegetable crops based on compost application and reduced soil tillage. The observed and simulated results indicated that systems with a fallow/vegetables cycle ratio > 2 and the monoculture of vegetables including compost applications at ≥ 10 Mg ha− 1 yr− 1 presented C sequestration corresponding to SOC increases of 10% and 3% of the initial stock, respectively. The monoculture of vegetables with a compost rate < 10 Mg ha− 1 yr− 1 and systems including vegetables in rotation with export crops and a short fallow cycle presented a reduction in SOC that ranged from 10% to 18%. Pedoclimatic conditions had a lower impact on SOC changes. Similar socio-economic profiles of farmers were observed for farm types including very different cropping systems. The model well described SOC changes for each farm type and offered valuable insights about the factors affecting SOC losses and C sequestration. The framework proposed in this study was helpful to identify improved managements that can maintain or increase SOC stocks under tropical conditions.
Original languageEnglish
Pages (from-to)172-180
JournalAgricultural Systems
Volume153
DOIs
Publication statusPublished - 1 May 2017
Externally publishedYes

Funding

This study formed part of the TropEmis Project funded by the Reacctif Programme of the French Environment and Energy Management Agency (ADEME) (Grant no 410-00159), the European Regional Development Fund (FEDER) (Grant no 410-00160) and the Regional Council of Guadeloupe (Grant no. 410-00161). We are grateful to the 71 farmers who were interviewed for this study. We would like to thank Dominique David for his assistance during soil sampling and Victoria Hawken for reviewing the English manuscript. We thank the three anonymous reviewers for their constructive comments, which helped us to improve the manuscript.

FundersFunder number
Agence de l'Environnement et de la Maîtrise de l'Energie410-00159
European Regional Development Fund410-00160
Conseil Regional de la Guadeloupe410-00161

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