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.

本文评估了热带地区农业土地每千分之四计划的可行性，特别是在瓜德罗普岛，作为加勒比和其他热带地区的代表性案例研究。我们使用了经过局部调整和校准的模型，该模型描述了在气候变化影响下的土壤有机碳动态变化以及各种情景，这些情景结合了增加使用有机改良剂，减少土壤耕种和增加本地市场土地面积的情况。我们发现，在目前的状态下，只有26％的农业面积可以达到4‰年^-1在未来30年中，土壤有机碳（SOC）储量将增加，这主要是由于多年生作物系统（蔗糖，香蕉，果园）占据了SOC储量最低的土壤。通过增加使用本地生产的堆肥来减少耕种，将使农业面积达到每千分之四的目标，达到31％。但是，在领土范围内，所有测试的情景都表明，SOC的存量逐年减少，范围从− 0.1到− 3.2‰。每1000个目标中有4个目标的有限区域是可行的，并且普遍的SOC损失主要与岛上火山和钙质土壤中当前的高SOC存量有关，并且缺乏能够进一步增加当前种植系统中碳输入的实践。我们得出的结论是，加勒比海地区的碳固存潜力相当有限，而且SOC存量不断增加，