"Today's scientific evidence demonstrates that agroecological methods outperform the use of chemical fertilizers in boosting food production where the hungry live -- especially in unfavorable environments," said Olivier De Schutter, the UN Special Rapporteur. "To date, agroecological projects have shown an average crop yield increase of 80 percent in 57 developing countries, with an average increase of 116 percent for all African projects. Recent projects conducted in 20 African countries demonstrated a doubling of crop yields over a period of three to ten years."
Malawi is cited as an example.
http://www.srfood.org/images/stories/pdf/press_releases/20110308_agroecology-report-pr_en.pdf