Low soil fertility is a major concern in agricultural productivity and development policy discourse in sub-saharan Africa. The problem is exacerbated by government withdrawal from fertilizer input markets and the inability of private sector operators to fill the gap. This warranted a search for other nutrient sources to supplement chemical fertilizers. Based on field data collected in Zambia, this study assessed the labor inputs implications of “improved tree fallows”, continuous maize cropping with and without mineral fertilizer and, evaluated the financial profitability of the different land use systems. Results show that agroforestry-based land use systems are more profitable (NPV between $233 and $309 per ha) than farmers’ practice of continuous maize production without external fertilization ($130/ha) but, they are less profitable than mineral fertilizer ($499). When the effects of the 50% government subsidy on fertilizers are taken into account, the differences in the profitability of fertilizers over improved tree fallows falls from 61% to 13%. The returns per person labor-day is $3.20 for fertilizer and $2.50, $2.40, and $1.90 respectively, for the three agroforestry options evaluated and only $1.10 for unfertilized maize. These returns compare with a daily agricultural wage of $0.50 in the study area. Key determinants of financial attractiveness and by extension, potential adoptability of the land use systems were identified. Given the low rate (20%) of farmers in Zambia who have access to fertilizers, there is a large niche to integrate other soil nutrient replenishing options with fertilizer to improve food security and reduce poverty among resource-poor smallholder farmers in Africa.