Potential and constraints for applying the \u201c4 per 1000 Initiative\u201d in the Caribbean: the case of Guadeloupe

Jorge Sierra,Pierre Chopin

doi:10.1007/s10113-020-01740-4

Abstract

This paper assesses the feasibility of the 4 per 1000 initiative for agricultural soils in the tropics more specifically in Guadeloupe, as a representative case study of the Caribbean and other tropical regions. We used a locally adapted and calibrated model describing soil organic carbon dynamics under the impact of climate change and a broad range of scenarios combining increased use of organic amendments, reduced soil tillage, and increased land area for the local market. We found that, in its current state, only 26% of agricultural area could achieve a 4‰ year−1 increase in soil organic carbon (SOC) stocks in the coming 30 years, due mainly to perennial cropping systems (sugarcane, banana, orchards) occupying soils with the lowest SOC stocks. Implementing reduced tillage with increased use of locally produced composts would increase the agricultural area reaching the 4 per 1000 target to 31%. However, at territory scale, all scenarios tested showed an annual decrease in SOC stocks varying from − 0.1 to − 3.2‰. The limited area on which the 4 per 1000 target is feasible and generalized SOC losses were mainly linked to the current high SOC stocks in volcanic and calcareous soils on the island and lack of practices capable of further increasing C inputs in current cropping systems. We concluded that C sequestration potential in the Caribbean is rather limited and that increasing SOC stocks, even lower than 4 per 1000, should be the primary target in adaptation to climate change, by increasing the resilience of cropping systems based mainly on SOC-poor soils.

Highlights

IntroductionConference (COP21) in Paris in 2015 aims at increasing global soil organic carbon (SOC) stocks by 4 per 1000 (or 0.4%) per year to compensate for global anthropogenic emissions of fossil C (Soussana et al 2019)
The “4 per 1000 Initiative: Soils for Food Security and Climate” proposed at the United Nations Climate ChangeCommunicated by Cornelia Rumpel and accepted by Topical Collection Chief Editor Christopher Reyer This article is part of the Topical Collection on Regional management practices with positive effects on soil carbon to meet the goals of the 4p1000 initiativeConference (COP21) in Paris in 2015 aims at increasing global soil organic carbon (SOC) stocks by 4 per 1000 per year to compensate for global anthropogenic emissions of fossil C (Soussana et al 2019)
The analysis was performed for the reference or business-asusual scenario, i.e., the current situation without any change in the area occupied by the cropping systems or in farming practices

Summary

Introduction

Conference (COP21) in Paris in 2015 aims at increasing global soil organic carbon (SOC) stocks by 4 per 1000 (or 0.4%) per year to compensate for global anthropogenic emissions of fossil C (Soussana et al 2019) This initiative acknowledges the key role of soils in addressing the three-fold challenge of food security, adaptation to climate change, and mitigation of human-induced greenhouse gas (GHG) emissions (Minasny et al 2018; Lal 2020). In a literature review on SOC storage in soils in sub-Saharan Africa, Corbeels et al (2019) reported SOC increases > 4‰ year−1 when no-till or minimum tillage, crop residue retention, and intercropping or rotation were applied simultaneously They concluded that, there is high potential for application of the “4 per 1000 Initiative” in tropical degraded soils, low SOC levels are largely the result of the limited resources available to most smallholder farmers in these regions (Corbeels et al 2019)

Objectives

Methods

Results

Discussion

Conclusion