Lessons learnt from analyses of the water footprint of tomatoes and olive oil in Spain
ABSTRACT: This chapter evaluates the water footprint (WF) of Spanish tomatoes and olive oil over the period 1997-2008. It analyses the three types of water: green, blue and grey. Water apparent productivity (WAP) and virtual water exports for tomatoes and olive oil have been studied. The ranges of the WF of tomatoes and olives per unit of product (m3/t) show that providing a unique value for a product WF may be a strong assumption because of the widely different climatic conditions, production systems, productivity levels and irrigation schedules across the country. The greenhouse tomato system presents the greatest WAP, which is influenced by the much higher price of off-season productions and larger crop yield. However, tomato production also shows a high grey WF, implying a pressure over water resources related to nitrogen pollution. The increase of groundwater consumption in the upstream Guadalquivir basin caused concerns about the sustainability of olive irrigation. Recently, the situation seems to be under control given the deficit irrigation practices and the constraints imposed by the sharp increase in energy prices. The virtual water related to olive oil exports illustrates still the importance of the green water footprint of rainfed olives amounting to about 77% of the total virtual water exports.