Carbon footprint of smallholder farms in Central Madagascar: The integration of agroecological practices

摘要

The carbon footprint (CFP) assessment of smallholders offers key information on the capacities and challenges for greenhouse gas (GHG) mitigation at farm scale. This allows prioritizing the practices that ensure both the food security of farmers and the low carbon impact associated to climate change. To tackle food security challenges and to maintain sustainable environment production, agroecological practices were planned for farmers in the Itasy region, Central Highlands of Madagascar. The project consisted of agroforestry and forestry systems, composting of organic matters, and system of rice intensification. The goals of this study were (i) to assess the CFP of farms in the Itasy region Central Madagascar, (ii) to assess the impact of agroecological practices adopted by farmers on farms CFP, and (iii) to compare the impact of Tier 1 and Tier 3 factors for carbon removal in woody biomass and in cropland soils on farms CFP. For these purposes, a survey of 192 representative farms was realized during the years 2012-2013. Agroecological practices integrated at farm scale reduced significantly farms CFP up to 364% in terms of land surface and up to 578% in terms of food production, suggesting an important GHG sequestration at farm scale. Main sources of GHG at farms scale were: nitrous oxide from soil management (25%), methane from rice cultivation (24%), livestock manure management (24%), and enteric fermentation (23%). Trees planted in agroforestry and forestry systems offered the highest GHG mitigation benefits. Tier 1 factors overestimated up to 7 times higher the farms CFP compared to Tier 3 factors. This study highlights that the integration of agro-ecological practices at farm scale offers significant GHG mitigation and carbon sequestration in Malagasy context, thus giving an alternative for climate change mitigation. (C) 2016 Elsevier Ltd. All rights reserved.