Rather than raising crop yields per hectare, the West African country's agricultural growth depended predominantly on expanding the cropped area, through clearing virgin forests and reducing the length of traditional fallow periods, the researchers noted.

In a new book titled "Ghana's Economic and Agricultural Transformation: Past Performance and Future Prospects", researchers have established that this pattern of crop production is unsustainable and environmentally damaging.

The authors are Danielle Resnick, a senior research fellow, and Xinshen Diao, deputy director in the development strategy and governance division of the International Food Policy Research Institute, United States, as well as Peter Hazell and Shashidhara Kolavalli, independent researchers based in the US.

"This pattern of growth has reduced Ghana's competitiveness in developing agricultural exports other than cocoa, and in competing with imports like rice, poultry, and processed foods," the summary of the findings sent to Xinhua revealed.

"There is relatively little virgin forest left, and the reduction of fallow periods is leading to serious soil fertility problems which have been masked so far by the increased use of inorganic fertilizers to replace lost nutrients rather than to raise yields," it added.

The researchers urged the West African country, which exports gold, cocoa, and crude oil, to adopt more intensive agricultural practices that raise land as well as labor productivity.

Ghana has long been depending on rain-fed agriculture for food production, with food preservation at its basic stage.