s:1275:"TI Contributions of agroforestry research to livelihood of smallholder farmers in Southern Africa: 1. taking stock of the adaptation, adoption and impact of fertilizer tree options 
AU Akinnifesi, F.K. 
AU Chirwa, P.W. 
AU Ajayi, O.C. 
AU Sileshi, G. 
AU Matakala, P. 
AU Kwesiga, F.R. 
AU Harawa, H. 
AU Makumba, W. 
AB Agroforestry practies involving fertilizer trees managed in sequential and simultaneous tree-crop systems are key to achieving sustainable food production in Southern Africa as they offer a wider scope for resource-stressed farmers to produce sufficient food for consumption and markets, even where land scarcity and soil fertility are major constraints. In these systems, maize yields have generally increased from less than a tonne per hectare to two or more tonnes, in Malawi, Tanzania, Zambia and Zimbabwe and they have been shown to be comparable to fertilized fields. Application of micro doses of inorganic fertilizers (especially N) in tree-crop systems has generally increased the synergy in nutrient availability thereby producing higher maize yields than unfertilized maize. Fertilizer tree systems are more productive and economically more profitable than unfertilized maize system and the economic impact is high, estimated at US 
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