Water scarcity footprint of cocoa irrigation in Bahia

Abstract This study simulated the water scarcity footprint (WSF) of cocoa irrigation in municipalities considered suitable for cocoa growing in the state of Bahia, according to agro climatic zoning. Irrigation demand was calculated using the model proposed by FAO (Food and Agriculture Organization of the United Nations). Subsequently, impact on water scarcity was calculated using the product of crop irrigation demand and water scarcity characterization factors of the regionalized AWARE method for Brazil. The WSF in Bahia ranged between 0.28 and 646.5 m³ of water per kilo of cocoa produced. From the defined scale, of the 417 municipalities in Bahia suitable for growing cocoa, 59% have a 'low' footprint, 18% 'medium', 10% 'high', and 12% have a 'very high' footprint. Based on these results, it is suggested that areas with lower WSF are a priority in the expansion of cocoa to avoid a possible compromise of other essential demands of the municipalities. In addition, irrigation should avoid waste, especially in regions with high levels of water scarcity. The results show that the inclusion of the WSF in agroclimatic zoning can contribute to the process of identifying potential and critical regions for new crops and the expansion of others.

摘要 本研究基于农业气候区划，对巴西巴伊亚州适宜可可种植的市镇开展可可灌溉水资源短缺足迹（water scarcity footprint, WSF）模拟研究。本研究采用联合国粮食及农业组织（Food and Agriculture Organization of the United Nations, FAO）提出的模型计算作物灌溉需水量；随后结合巴西分区AWARE方法的水资源短缺特征因子，通过作物灌溉需水量与该特征因子的乘积计算水资源短缺影响。巴伊亚州的WSF区间为每生产1千克可可需水0.28~646.5立方米。基于划定的分级标准，在该州417个适宜可可种植的市镇中，59%的水资源短缺足迹等级为“低”，18%为“中”，10%为“高”，12%为“极高”。基于上述结果，研究建议优先在水资源短缺足迹较低的区域开展可可种植扩张，以避免对市镇其他必要用水需求造成潜在影响；此外应避免灌溉用水浪费，尤其在水资源短缺程度较高的区域。研究结果表明，将水资源短缺足迹纳入农业气候区划，有助于识别适宜新增种植作物以及现有作物扩张的潜力区域与关键区域。