Neo-colonial, is how director Jacques Diouf of the UN's Food and Agricultural Organisation (FAO) has branded the practice. Since 2006, developing countries have leased 15 to 20 million hectares of farm land to foreign investors, according to a study by the International Food Policy Research Institute - a territory equal to the total farming area of France - with a turnover of 20 to 30 billion dollars since 2006.

New research commissioned by the FAO and the International Fund for Agricultural Development (IFAD, also a UN organisation) says the leasing of farm land to foreign companies, investment funds and foreign governments is now a worldwide phenomenon. The study, conducted together with the British International Institute for Environment and Development (IIED), concentrated on five African countries - Ethiopia, Ghana, Madagascar, Mali and Sudan - where 2.5 million hectares of farm land have been leased out since 2004.

Feeding the rich According to the study Land grab or development opportunity? Agricultural investment and international land deals in Africa, it is mainly Middle-Eastern and Asian countries and companies that are leasing farm land in Africa. The cheap and abundant African farm land is used to secure the food supply for populations in oil-rich countries with poor agricultural infrastructures. An investment fund from Abu Dhabi, for instance, has leased 28.000 hectares in Sudan to produce corn, beans and potatoes for the United Arab Emirates. A consortium of Saudi Arabian agricultural companies has announced it will invest 400 million dollars in food production in Sudan and Ethiopia. Bio-fuel is another reason to lease African land. The British energy company CAMS Group announced last year it had leased 45.000 hectares in Tanzania for the production of sorghum, a weed that can be used to produce bio-fuel. Once in a while it is the other way around and an African country gets its food from Europe: Lybia last year entered into an oil-for-grain agreement with Ukraine.

The main investors are semi-government companies and investment companies from oil-rich countries in the Middle East and Asia where fast growth and consequent high demand for fuel and food go hand in hand with poor agricultural facilities. Qatar and Kuwait, for instance, are big investors in Sudan. Ethiopia has leased farm land to Saudi Arabia.

The researchers warn against jumping to conclusions about the effect of the practice on African countries. "Africa has been dying for decades to attract more foreign investment, so let's not shoot ourselves in the foot," Harold Liversage, an IFAD researcher, told Reuters press agency.

But they also point to the dangers. Many African countries lack efficient property and environmental laws. In the absence of clear agreements, "there is a risk of poor people being chased off their land or loosing access to land, water or other necessities," the study warns.

One bad example is Madagascar, where Daewoo from South Korea leased 1.3 million hectares of farm land - half of all the farm land on the island. The deal raised anger among poor Madagascans and led to a popular uprising that culminated in president Marc Ravalomanana being removed in a coup led by the populist Andry Rajoelina.

The debate over leased farm land is similar to the one about Chinese investments in Africa. Critics say China investing in infrastructure in Africa in exchange for natural resources is neo-colonial too. But supporters say the cheap loans and investments provided by China are beneficial to African countries.

China, by the way, is not looking for food from Africa. Its land deals in Africa are for bio-fuel or for pure investment purposes. For its food supply, China prefers to look to South-East Asia.