The switch by many farmers in Kenya's Rift Valley province from staple cereals to more profitable coffee is likely to increase the country's dependence on grain imports and possibly affect food security, agricultural experts have warned. 'It is unsafe to use our land for crops with the hopes of being fed by other countries,' said James Nyoro, managing director for Africa of the Rockefeller Foundation. Kenya will have to import 2.3 million tonnes of cereal during the 2011-2012 marketing year to meet demand, a year-on-year increase of 37 per cent, according to the UN Food and Agricultural Organisation, which estimated domestic harvests of maize - a staple for 90 per cent of Kenyans - at 2.5 million tonnes, down 18 per cent because of poor weather.