Green and Blue Water Footprint Accounting for Dry Beans (Phaseolus vulgaris) in Primary Region of Mexico

Water shortages are a key obstacle to the sustainable supply of food to the world population, since agriculture has the largest consumptive water use. The Water Footprint (WF) has been developed as a useful tool to assess the contribution of goods and activities to water scarcity. This concept is being used around the world to improve agricultural water management. This paper analyzes climate data in order to estimate green and blue WFs for dry beans in the dry beans primary region of Mexico under both irrigation and dryland conditions. The quantification of green WF is very important in this area, since 95% of the crop is obtained in dryland conditions. Standard methodology was used to assess the crop WF. Five different sowing dates were considered: two for irrigation (15 April and 15 May) and three for dryland (1 and 15 July and 1 August). It was found that the optimum sowing date for dryland conditions is 1 August, with a WF of 1839 m3·Mg−1 (1 Mg equal to 1000 kg) in the sutheastern part of the region; nevertheless, results show that the largest green water availability occurs around the first days of July. Under irrigated conditions the best sowing date is 15 May, with a decrease in crop evapotranspiration of 10.1% in relation to 15 April; which means a reduction of 36.1% of blue water use in the northwestern region mainly