1Laboratoire des Productions Animale et Fourragère,Institut National de la Recherche Agronomique de Tunisie (INRAT),Université de Carthage, rue Hédi Karray,2049 Ariana,Tunisia.
Animal. 2019 Feb;13(2):407-416. doi: 10.1017/S1751731118001593. Epub 2018 Jul 9.
Water scarcity is among the main challenges making vulnerable the livestock farming systems in drylands. The water footprint (WF) indicator was proposed as a metric to measure the impacts of livestock production on freshwater resources. Therefore, this study aimed to assess water use in five different Tunisian sheep production systems using the Water Footprint Network methodology. The primary data were obtained from 1050 sheep farms located in 13 Tunisian provinces. A multivariate analysis was performed to characterize the different farming systems. A validation step of the WF modeled values of sheep meat was conducted in 12 sheep farms belonging to two different farming systems. This was done through year-round monitoring of on-farm practices using water metres and recording equipment's taking into account the direct and indirect water use. The typology analysis came up with five sheep farming systems that are the mixed sheep-cereal (MSC), the agro-sylvo-pastoral (ASP), the agro-pastoral (AP), the extensive agro-pastoral (EAP) and the mixed sheep-olive tree farming systems. The WF of sheep meat produced under the target farming systems ranged from 8654 to 13 056 l/kg live weight. The evaluation of WF of five different sheep production systems figured out that sheep raised under the EAP farming system had the greatest WF per ton of live animal. However, the ASP farming system exhibited the lowest WF. Water used to grow feedstuffs for sheep production accounts for 98% of the total WF of sheep. The green WF accounts for more than 92% of the total WF in all farming systems. Results of monitoring water use at farm scale show that the modeled values of WF are overestimated by an average of 23.3% and 24.1% for the selected farms assigned to the MSC and AP farming systems, respectively. Water use for sheep production is high in most of the Tunisian farms. Therefore, the general assumption that 'meat production is a driver of water scarcity' is supported and should be considered as an important focal point in agricultural and water policies. Particular attention should be given to forage crops with low WFs and high contribution to dry matter to provide ration with low WF. The efficient use of green water along the meat value chain is essential to minimize the depletion of blue water resources and to reduce the economic dependency on virtual water through the import of feedstuffs.
水资源短缺是干旱地区畜牧业系统面临的主要挑战之一。水足迹（WF）指标被提出作为衡量畜牧业生产对淡水资源影响的指标。因此，本研究旨在使用水足迹网络方法评估突尼斯五个不同绵羊生产系统的用水量。主要数据来自位于突尼斯 13 个省份的 1050 个绵羊养殖场。采用多元分析对不同的养殖系统进行了特征描述。对两个不同养殖系统的 12 个绵羊养殖场的绵羊肉 WF 模型值进行了验证。这是通过使用水表和记录设备全年监测农场实践，并考虑直接和间接用水量来完成的。通过对五个绵羊养殖系统的分类分析，得出了混合绵羊-谷物（MSC）、农林牧复合（ASP）、农牧（AP）、粗放农牧（EAP）和混合绵羊-橄榄树养殖系统。目标养殖系统下生产的绵羊肉的 WF 范围为 8654 至 13056 升/公斤活重。对五个不同绵羊生产系统 WF 的评估表明，EAP 养殖系统下饲养的绵羊每头活畜的 WF 最大。然而，ASP 养殖系统的 WF 最低。用于饲养绵羊的饲料用水量占绵羊总 WF 的 98%。在所有养殖系统中，绿色 WF 占总 WF 的 92%以上。农场规模的用水量监测结果表明，对于分配给 MSC 和 AP 养殖系统的选定农场，WF 模型值的平均高估了 23.3%和 24.1%。在大多数突尼斯农场，绵羊生产的用水量都很高。因此，“肉类生产是水资源短缺的驱动因素”这一普遍假设得到了支持，应该被视为农业和水政策的一个重要焦点。应特别关注 WF 低、对干物质贡献高的饲料作物，以提供 WF 低的日粮。沿肉类价值链有效利用绿水对于最小化蓝水资源的枯竭以及通过进口饲料减少对虚拟水的经济依赖至关重要。
