The evidence does not support gloomy generalizations about an irreversible African environmental crisis or pessimistic arguments that barriers to adopting Green Revolution technologies are insuperable. Although evidence on agricultural technology in Africa is often unreliable, food output and grain yields do appear to have risen strongly in some African economies.. Huge variations in crop yields, including within similar agro-ecological zones, suggest massive potential for policies to promote a rapid increase in yields. Agricultural research and development (R&D) within African countries—and production on many large-scale farms—has shown that dramatically higher yields are possible. Crop yield improvements—with the aid of suitable high-yield varieties (HYVs), public agricultural research spending, and especially investment in irrigation—are possible without draconian resettlement schemes, without wasteful extension service spending, and without recourse to micro-finance schemes. The methods underpinning commonly produced estimates of yields are unreliable, calling into question conventional wisdom that small farms are more efficient than larger farms.
Rates of return to public agricultural research in 48 US states