Rather it is the production of soy that has grown 10 times, not the area devoted to soy.
That said, soy cultivated area has grown from 24 million to 106 million ha, growing 4.4 times since 1961. This impressive growth in area devoted to soy cultivation has nonetheless been less than production growth, partly due to the doubling of soy yields since the 1960’s (Masuda and Goldsmith, 2009).
Projections have suggested the yields could rise by a further 50 per cent globally by 2050 (Bruinsma, 2009), but this will be hugely challenging. Brazil and Argentina have invested heavily in research and crop breeding to increase yields, but the large productivity gains they have experienced are expected to tail off sharply.
Even with higher yields per hectare, however, FAO calculates that by 2050 the soy-growing area will need to increase by almost half as much again (up to 141 million ha from 95 million ha in 2005-07).