ConclusionsNew considerations were proposed to quantify blue and graywater footprint in a fertirrigated crop under different rates of Nmineral fertilization in semiarid conditions, where irrigation is nec-essary to maintain the production, and where higher volumes ofwater are needed to avoid soil salt accumulation preventing yieldloss. In our proposed method, since in these conditions green waterfootprint is zero because the effective rainfall is nule, efforts havebeen aimed at improving blue and gray water footprint. The bluewater footprint needs to include the extra consumption of waterirrigation that the farmer has to apply to compensate (i) the failof uniformity on discharge of drips, (ii) percolation losses or saltsleaching, which depends on the salt tolerance of the crop, soil andquality of irrigation water. With respect to gray water footprint,one has to consider all the N sources as N fertilizer rate, N contentin the irrigation water and N in the soil (mineral and mineralizedduring the crop period).The previous studies and proposed methodologies were used toquantify the water footprint in a three year experiment with fertir-rigated melon crop, using eleven different N rates ranging between11 and 393 kg ha−1.The treatments with the optimum N dose pre-sented values of water footprint between 127.8 and 151.7 m3t−1.The highest water footprint was obtained in the treatments witha N excess, with 226.0 and 355.0 m3t−1, while the treatmentswith the lowest N dose presented a water footprint between 145.7and 158.4 t ha−1. In both cases the values were higher than thoseobtained in the treatments with the optimum N dose.