Festus K. Akinnifesi

Evergreen Agriculture: a robust approach to sustainable food security in Africa

Producing more food for a growing population in the coming decades, while at the same time combating poverty and hunger, is a huge challenge facing African agriculture. The risks that come with climate change make this task more daunting. However, hundreds of thousands of rain fed smallholder farmers in Zambia, Malawi, Niger, and Burkina Faso have been shifting to farming systems that are restoring exhausted soils and are increasing food crop yields, household food security, and incomes. This article reviews these experiences, and their broader implications for African food security, as manifestations of Evergreen Agriculture, a fresh approach to achieving food security and environmental resilience. Evergreen Agriculture is defined as the integration of particular tree species into annual food crop systems. The intercropped trees sustain a green cover on the land throughout the year to maintain vegetative soil cover, bolster nutrient supply through nitrogen fixation and nutrient cycling, generate greater quantities of organic matter in soil surface residues, improve soil structure and water infiltration, increase greater direct production of food, fodder, fuel, fiber and income from products produced by the intercropped trees, enhance carbon storage both above-ground and below-ground, and induce more effective conservation of above- and below-ground biodiversity. Four national cases are reviewed where farmers are observed to be applying these principles on a major scale. The first case involves the experience of Zambia, where conservation farming programmes include the cultivation of food crops within an agroforest of the fertilizer tree Faidherbia albida. The second case is that of the Malawi Agroforestry Food Security Programme, which is integrating fertilizer, fodder, fruit, fuel wood, and timber tree production with food crops on small farms on a national scale. The third case is the dramatic expansion of Faidherbia albida agroforests in millet and sorghum production systems throughout Niger via assisted natural regeneration. The fourth case is the development of a unique type of planting pit technology (zai) along with farmer-managed natural regeneration of trees on a substantial scale in Burkina Faso. Lastly, we examine the current outlook for Evergreen Agriculture to be further adapted and scaled-up across the African continent.

Towards domestication of Jatropha curcas

Jatropha curcas L. attracts a lot of interest as a biofuel crop, triggering large investments and rapid expansion of cultivation areas, and yet, it should still be considered as a (semi-)wild, undomesticated plant. To use the full potential of Jatropha and to support further expansion and systematic selection, breeding and domestication are a prerequisite. This review reveals and identifies gaps in knowledge that still impede domestication of Jatropha. Prebreeding knowledge is limited. In particular, the regeneration ecology and the degree of genetic diversity among and within natural populations in and outside the center of origin are poorly studied. There is only a limited understanding of the Jatropha breeding system and the effect of inbreeding and outbreeding. This review presents all currently available and relevant information on the species distribution, site requirements, regeneration ecology, genetic diversity, advances in selection, development of varieties and hybridization. It also describes possible routes to a better Jatropha germplasm, gives recommendations for tackling current problems and provides guidance for future research. We also discuss the participatory domestication strategy of Jatropha integration in agroforestry.

TOWARDS THE DEVELOPMENT OF MIOMBO FRUIT TREES AS COMMERCIAL TREE CROPS IN SOUTHERN AFRICA

ABSTRACT Many rural households rely on indigenous fruit trees as sources of cash and subsistence in the Southern Africa Development Community (SADC), but until recently there has been little effort to cultivate, improve or add value to these fruits. Since 1989 the International Centre for Research in Agroforestry (ICRAF: now the World Agroforestry Centre) initiated research-and-development work on more than 20 priority indigenous fruit trees in five SADC countries aimed at improving income in rural communities. A participatory approach was used in all stages of their domestication, product development and commercialization. Country-specific priority species were identified in five countries based on discussions with a wide range of users. These species have now become the focus of a regional tree domestication programme. An impact analysis indicates that a robust domestication programme will create incentives for farmer-led investment in the cultivation of indigenous fruit trees, as an alternative to wild fruit collection, especially where there is a decrease in fruit abundance. In Zimbabwe, the returns to family labour of collecting wild fruits are two to three times greater than other farming activities. These returns will be further increased by domestication. Progress in the domestication of four priority fruit tree species Uapaca kirkiana, Strychnos cocculoides, Parinari curatellifolia and Sclerocarya birrea from the miombo woodlands in southern Africa is reviewed. Preliminary results indicate that the long juvenile phase of Uapaca kirkiana can be shortened from 12–16 years to less than four years, using vegetative propagation methods. On-going multidisciplinary tree crop domestication research includes molecular genetic analyses, tissue culture, post-harvest storage, production economics, nutritional analyses, market and supply chain surveys, processing and feasibility assessments of pilot enterprises. Holistic plans are needed to promote cultivation and ensure product quality on farms and to maximize competitiveness at the farm gate and throughout the supply chain.

Indigenous Fruit Trees in the Tropics: domestication, utilization and commercialization

[Extract] This book comprises 5 parts and 21 chapters discussing the domestication of indigenous fruit trees in Africa, Oceania, Latin America and Asia; and describes the biophysical and socio-economic aspects of Miombo fruit trees.

Agroforestry research and development in southern Africa during the 1990s: Review and challenges ahead

The International Centre for Research in Agroforestry (ICRAF) initiated in 1987 the Southern Africa Regional Agroforestry Programme in partnership with the national research systems in Malawi, Zambia, Zimbabwe and Tanzania to address the problems of low soil fertility and consequent low crop and livestock production, low cash income, and shortages of fuelwood and timber that are common to most rural households in the region. This paper synthesizes agroforestry research and development during the 1990s from a regional perspective and emphasizes scaling-up of promising technologies. The problem of nutrient-depletion can be overcome using nitrogen-fixing and fast growing tree/shrub species, such as Sesbania sesban, Tephrosia vogelii and Gliricidia sepium, as short-duration planted fallows in rotation with crops. Intercropping of food crops with coppicing trees, annual relay intercropping and biomass transfer technologies were found to be appropriate for soil fertility improvement under specific conditions. Tree fodder banks greatly increase fodder production and enrich livestock diets with protein supplements. Rotational woodlots were developed to meet fuelwood and timber demand and reduce pressure on natural woodlands. Research has identified the potential for a number of indigenous fruits in the region to supplement the food needs of rural families, improve their nutritional status and generate cash income. Achieving the ultimate goals of ensuring food security, alleviating poverty and sustaining the environment will require a massive scaling up of adoption of these agroforestry technologies. Key strategies to accomplish this include: increasing the benefits and targeting of agroforestry technologies (for example, through providing substitutes for costly inputs, improving diversification, marketing and processing of agroforestry products, and employing GIS-based targeting techniques) and information-sharing, training and collaborative partnerships in implementation and dissemination of agroforestry options with all major stakeholders (farmers, non-government organizations, extension services, educational institutions, and policy-makers).

SUSTAINABLE MAIZE PRODUCTION USING GLIRICIDIA/MAIZE INTERCROPPING IN SOUTHERN MALAWI

and without gliricidia trees), and three rates of inorganic N fertilizer (0, 24 and 48 N kg ha −1 representing 0, 25 and 50% of the national recommended N rate), and three rates of P fertilizer application (0, 20 and 40 P ha −1 representing 0, 50 and 100% of the recommended rate). No effect of P was detected on yield early in the trial, and this treatment was discontinued. The gliricidia pruning biomass did not decline after 10 years of intensive pruning, with strong correlation between tree biomass production and years after establishment (r = 0.91, p < 0.001). Application of gliricidia prunings increased maize yields by three times compared to the yield of unfertilized sole maize. Maize yield from the unfertilized gliricidia pruning treatment was superior to the yield from sole maize supplemented with a quarter or half the recommended N rate. The study confirmed that a gliricidia/maize intercropping system is a promising soil fertility replenishment option in southern Malawi and elsewhere in southern Africa.

Improving livelihoods and nutrition in sub-saharan africa through the promotion of indigenous and exotic fruit production in smallholders' agroforestry systems: A review

SUMMARY The cultivation of indigenous and exotic fruits for sub-Saharan Africas domestic markets can bring increased revenues for smallholders and improve the diets of local consumers. There are, however, many bottlenecks which need to be addressed so that wider benefits from such activities are realised. Here, we describe key interventions being taken to address current constraints. For indigenous fruit trees, it is necessary to set priorities for which species to promote and to engage in participatory domestication for the improvement of yield, quality and germplasm delivery to farmers. For exotic fruits, ‘south-south’ transfer of advanced cultivars and the development of small-scale commercial suppliers of planting material are required to reinvigorate production. For both indigenous and exotic species, a focus on improving market value chains to bring greater benefits to producers is needed. We describe where further work is required to increase efficiency in the sector and to favour smallholder involvement.

Fertiliser trees for sustainable food security in the maize-based production systems of East and Southern Africa. A review

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.

Biological nitrogen fixation and socioeconomic factors for legume production in sub-Saharan Africa: a review

Low crop productivity is a general problem facing most farming systems in sub-Saharan Africa (SSA). These low yields are pronounced in grain legumes and are often associated with declining soil fertility and reduced N2-fixation due to biological and environmental factors. Unfortunately, the majority of African small farmers are now unable to afford the high mineral fertilizer prices. More than 75% of the fertilizers used in Africa are imported, putting pressure on foreign exchange. Low cost and sustainable technical solutions compatible with the socioeconomic conditions of small farmers are needed to solve soil fertility problems. Biological nitrogen fixation (BNF), a key source of N for farmers using little or no fertilizer, constitutes one of the potential solutions and plays a key role in sustainable grain legumes (e.g., soybean) production. Given the high cost of fertilizer in Africa and the limited market infrastructure for farm inputs, current research and extension efforts have been directed to integrated nutrient management, in which legumes play a crucial role. Inoculation with compatible and appropriate rhizobia may be necessary where a low population of native rhizobial strains predominates and is one of the solutions which grain legume farmers can use to optimize yields. It is critical for sustained yield in farmlands deficient in native rhizobia and where N supply limits production. Research on use of Rhizobium inoculants for production of grain legumes showed it is a cheaper and usually more effective agronomic practice for ensuring adequate N nutrition of legumes, compared with the application of N fertilizer. Here, we review past and ongoing interventions in Rhizobium inoculation (with special reference to soybean) in the farming systems of SSA with a view to understanding the best way to effectively advise on future investments to enhance production and adoption of BNF and inoculant technologies in SSA. The major findings are: (1) complete absence of or very weak institutions, policy and budgetary support for biotechnology research and lack of its integration into wider agricultural and overall development objectives in SSA, (2) limited knowledge of inoculation responses of both promiscuous and specifically nodulating soybean varieties as well as the other factors that inhibit BNF, hence a weak basis for decision-making on biotechnology issues in SSA, (3) limited capacity and lack of sustainable investment, (4) poorly developed marketing channels and infrastructure, and limited involvement of the private sector in the distribution of inoculants, and (5) limited farmer awareness about and access to (much more than price) inoculants. The lessons learned include the need: (1) to increase investment in Rhizobium inoculation technology development, and strengthen policy and institutional support, (2) for public private partnership in the development, deployment and dissemination of BNF technologies, (3) to develop effective BNF dissemination strategies (including participatory approach) to reach farmers, (4) for greater emphasis on capacity building along the BNF value chain, and (5) for partnership between universities in SSA and those in the North on BNF research.

Agricultural success from Africa: the case of fertilizer tree systems in southern Africa (Malawi, Tanzania, Mozambique, Zambia and Zimbabwe)

In response to the declining soil fertility in southern Africa and the negative effects that this leads to, such as food insecurity besides other developmental challenges, fertilizer tree systems (FTS) were developed as technological innovation to help smallholder farmers to build soil organic matter and fertility in a sustainable manner. In this paper, we trace the historical background and highlight the developmental phases and outcomes of the technology. The synthesis shows that FTS are inexpensive technologies that significantly raise crop yields, reduce food insecurity and enhance environmental services and resilience of agro-ecologies. Many of the achievements recorded with FTS can be traced to some key factors: the availability of a suite of technological options that are appropriate in a range of different household and ecological circumstances, partnership between multiple institutions and disciplines in the development of the technology, active encouragement of farmer innovations in the adaptation process and proactive engagement of several consortia of partner institutions to scale up the technology in farming communities. It is recommended that smallholder farmers would benefit if rural development planners emphasize the merits of different fertility replenishment approaches and taking advantage of the synergy between FTS and mineral fertilizers rather than focusing on ‘organic vs. inorganic’ debates.