-The negative effects of soil fertility depletion on food security, especially among smallholder farmers in Africa, is of economic importance, and may be worsened by climate change and rising global fertiliser prices. Substantial efforts and investment have gone into development of alternative soil fertility management options. These include vigorous research and development of N-fixing plants or "fertiliser trees", that has been on-going in the last two decades in East and Southern Africa. In this paper, we review several studies conducted both on-station and on-farm and synthesise the results in terms of improvements in soil physical, chemical and biological properties, and crop yield in response to fertiliser trees. Our major findings are that (1) fertiliser trees add more than 60 kg N ha −1 per year through biological nitrogen fixation (BNF); (2) nutrient contributions from fertiliser tree biomass can reduce the requirement for mineral N fertiliser by 75%, translating to huge savings on mineral fertilisers; (3) fertiliser trees were also shown to substantially increase crop yield. A meta-analysis has further provided conclusive evidence that with good management, fertiliser trees can double maize yields compared with local farmer practices of maize cultivation without addition of external fertilisation. (4) Financial analyses showed that fertiliser tree systems are profitable and also have higher net returns than the farmers' de facto practice, i.e. continuous maize cropping without fertiliser. We conclude that widespread adoption and scaling up of fertiliser trees can reduce the amount of mineral fertiliser needed, maintain the soil ecosystem, and positively impact on the livelihoods of farm households in southern Africa.

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Several agro-ecological practices have been developed to increase the range of soil fertility management options available to farmers, but little information is available on their labour input requirement and profitability relative to conventional practices. This study used a multiple visit cost-route method to estimate labour inputs and financial profitability of agroforestry-based and conventional (with and without fertiliser) soil fertility management practices in eastern Zambia. Results show that aggregated over a five-year cycle, labour inputs used under agroforestry practices were lower than fertilised maize fields but higher than non-fertilised continuous cropped maize. Agroforestry practices were more profitable (NPV ranging between $233 and $327 ha -1 ) than unfertilised maize fields (NPV of $130 ha -1 ) but less profitable than fertilised maize fields. The NPV for the latter is $499 ha -1 under a 50% government subsidy on fertiliser but, it fell to $349 ha -1 when the subsidy effect is removed. In terms of return per unit investment cost, agroforestry practices performed better with a benefit to cost ratio ranging between 2.77 to 3.13 in contrast to 2.65 (subsidised fertiliser) and 1.77 (non-subsidised fertiliser). The returns to labour per person day was $2.56 in (non-subsidised) fertilised maize field, $3.16 in subsidised fertiliser field, $2.63 in Gliricidia fields, $2.41 in Sesbania fields, $1.90 in Tephrosia fields, and $1.10 in non-fertilised maize fields. The results do not support the popular notion that agroforestry practices are more labour intensive. It suggests that in addition to total labour use requirements, the temporal distribution of labour use during the farming season is important. It is concluded that agroforestry practices are profitable, and could contribute to food security.

Based on field data collected from 131 small scale dairy farmers that were randomly selected from four agro-ecological zones, this study assessed the potential of adoption of fodder bank technology as a means for improving livestock production and income generation for smallholder farmers in Zimbabwe. Using a logit modelling approach, it also identified the drivers of adoption of the technology by analysing the influence of household characteristics and ecological factors on farmers' decision to adopt the technology. The model correctly predicted 75% of observed adoption and non-adoption by farmers. Results reveal that dairy herd size, land holding size, membership of dairy association and agro-ecological potential are the key factors influencing farmers' adoption of fodder bank. Age, sex, household size and educational level of farmers play lesser role. Male and female farmers were equally likely to take up and practice fodder bank if they are given equal access to information and incentives. The study recommends farmer-led extension approaches where farmers who possess certain key characteristics should constitute the initial group for disseminating information regarding the technology in rural communities. The results highlight the importance of access to dairy product markets as a driver for the adoption of fodder banks. It is recommended that forging a strategic partnership with the Dairy Development Programme (DDP) will offer high potential for enhancing the scaling up of the adoption and impact of fodder bank technology in the country.

-The negative effects of soil fertility depletion on food security, especially among smallholder farmers in Africa, is of economic importance, and may be worsened by climate change and rising global fertiliser prices. Substantial efforts and investment have gone into development of alternative soil fertility management options. These include vigorous research and development of N-fixing plants or "fertiliser trees", that has been on-going in the last two decades in East and Southern Africa. In this paper, we review several studies conducted both on-station and on-farm and synthesise the results in terms of improvements in soil physical, chemical and biological properties, and crop yield in response to fertiliser trees. Our major findings are that (1) fertiliser trees add more than 60 kg N ha −1 per year through biological nitrogen fixation (BNF); (2) nutrient contributions from fertiliser tree biomass can reduce the requirement for mineral N fertiliser by 75%, translating to huge savings on mineral fertilisers; (3) fertiliser trees were also shown to substantially increase crop yield. A meta-analysis has further provided conclusive evidence that with good management, fertiliser trees can double maize yields compared with local farmer practices of maize cultivation without addition of external fertilisation. (4) Financial analyses showed that fertiliser tree systems are profitable and also have higher net returns than the farmers' de facto practice, i.e. continuous maize cropping without fertiliser. We conclude that widespread adoption and scaling up of fertiliser trees can reduce the amount of mineral fertiliser needed, maintain the soil ecosystem, and positively impact on the livelihoods of farm households in southern Africa.