Quantifying blue and green virtual water contents in global crop production as well as potential production losses without irrigation

摘要: Summary Crop production requires large amounts of green and blue water. We developed the new global crop water model GCWM to compute consumptive use (evapotranspiration) virtual content (evapotranspiration per harvested biomass) crops at a spatial resolution 5′ by 5′, distinguishing 26 classes, versus is based on land data set MIRCA2000 that provides monthly growing areas for classes under rainfed irrigated conditions period 1998–2002 represents multi-cropping. By computing daily soil balances, determines evapotranspiration each grid cell. Cell-specific both computed downscaling average yields reported 402 national sub-national statistical units, relating in census statistics simulated ratios actual potential crops. restricting only, loss without any irrigation was computed. For 1998–2002, value total 6685 km 3  yr −1 , which 1180 km 919 km 4586 km . Total largest rice (941 km ), wheat (858 km ) maize (722 km ). The were used (307 km (208 km Blue as percentage highest date palms (85%), cotton (39%), citrus fruits (33%), (33%) sugar beets (32%), while cassava, oil palm cocoa, almost no used. Average yield cereals 442 Mg km −2 only 266 Mg km cereal 1109 m  Mg 291 m water, productivity 714 g m −3 If currently not irrigated, dates, rice, cotton, cane would decrease 60%, 39%, 38%, 32% 31%, respectively. Forty-three cent land, irrigation, 47%, corresponding 20% production. losses occur Northern Africa (66%) Southern Asia (45%) be very low Europe (0.001%), Western (1.2%), Eastern (1.5%) Middle (1.6%). Uncertainties limitations are discussed manuscript, comparison results or other studies shows good agreement regional scale, but larger differences specific countries.