On the high plains around the town of Luiz Eduardo Magalhães in central Brazil, it is easy to feel dwarfed by the landscape. Fields of soya, maize and cotton stretch to the horizon under immense blue skies, only the occasional tree, silo or patch of scrubby cerrado woodland giving any sense of scale. Twin-wagoned lorries are laden with soya thunder along the highways. Away from the main roads, human beings are a rarity, glimpsed only in the cabins of combine harvesters or, in the late afternoon as the air…