The water footprint and virtual water exports of Spanish tomatoes

D. CHICO et al. 39where the main production system is open-air irrigation.In many cases (though not exclusively) this type of productionis intended for processing tomato, as in the MiddleGuadiana and Ebro Valleys, which has a lower marketprice. Groundwater is generally used in areas where theproduction is intended for export and has higher prices.These results confirm previous studies that claim thatagriculture using groundwater is economically more productivethat using surface water (Hernández-Mora et al.,2001; Llamas and Martínez-Santos, 2005). This differencecan be attributed to several causes: the greater controland supply guarantee that groundwater provides, whichin turn allows farmers to introduce more efficient irrigationtechniques and more profitable crops; the greater dynamismthat has characterized the farmer that hassought out his own sources of water and bears the fullcosts of drilling, pumping and distribution; and the factthat the higher financial costs farmers bear motivatesthem to look for more profitable crops that will allow themto maximize their return on investments (Hernández-Mora et al., 2001).Finally, as for the water footprint of tomato exports, theywere assigned to each province proportionally to their shareof the national production. The international trade database(DataComex) of the Spanish Ministry of Industry,Tourism and Commerce reflects where the amount of tomatoesleft the country, not where they were produced. Hadwe applied the water footprint of the exporting province tothe tomatoes exported, it would have meant an overestimationof the water footprint of the exports of the provinceswith intensive international commerce while ignoring thoseproducing the tomatoes. In any case, a more detailed analysisof the export character of particular provinces would beadvisable to better quantify the water footprint other nationshave in Spain.