By Mario Osava RIO DE JANEIRO, Mar 24 (IPS) - It is a question of "national sovereignty, not xenophobia," said the president of Brazil’s land reform agency, INCRA, explaining the need to regulate foreign land ownership in Brazil. The biofuel frenzy has driven growing purchases of land in Brazil in the last few years, by local and foreign investors alike. Global financier George Soros, Microsoft chairman Bill Gates, the owners of Google and former U.S. president Bill Clinton (1993-2001) have all bought land or are partners in companies dedicated to the development of bioenergy in this country.