Keywords: Virtual water, evapotranspiration, productive grassland, meat production, water requirement, food security, rainwater.
Based on evapotranspiration demand for crops, the additional amount of water needed for the extra food production for the coming four decades is estimated at about 2,000—4,000 km3 (2—4 x 1015 litres), depending on diet, and water productivity increase. These amounts are equivalent to the evapotranspiration of a production area of about half to one billion hectares of land respectively, at grain yields of four tonnes per hectare. This additional water can be ‘incorporated’ in our food through increased yield with an associated water productivity increase on the current arable area of some 35-70% and/or through expansion of the arable area. Enhancing the use of grasslands for increasing red meat production by ruminants may be an essential way to capture part of this additional water to increase the availability of healthy food products for poor and food insecure people. We estimate that the production of ruminant meat on improved grasslands can make a significant contribution to substitute expansion of arable land area. Though these gains may not be easily achieved, this is true overall for any option to enhance use efficiency of natural resources to increase productivity and improve food security.
Prem Bindraban, Sjaak Conijn, Raymond Jongschaap, Jing Qi, Munir Hanjra, Jacob Kijne, Pasquale Steduto, Henk Udo, Theib Owels and Imke de Boer.
ISRIC — World Soil Information, PO Box 353 6700 AJ, Wageningen, The Netherlands.
22 pages, 2 figures, 3 tables, 68 references.