Best practices for maize production in the West African savannas

Alpha Y. Kamara,

Maize is the top staple and cereal crop in sub-Saharan Africa. Photo by IITA
Maize is the top staple and cereal crop in sub-Saharan Africa. Photo by IITA

In the past two decades, maize has spread rapidly into the moist savannas of West Africa, replacing traditional cereal crops such as sorghum and millet, particularly in areas with good access to fertilizer inputs and markets.

In the West African moist savannas, higher radiation levels, lower night temperatures, and a reduced incidence of diseases and insect pests have helped to increase maize yield potentials compared with traditional areas for maize cultivation (Kassam et al. 1975). Because of the availability of short-season early maturing varieties, cultivation has gradually spread to the Sudan savanna where the growing period is 90–100 days. Despite the expansion in these production areas, maize yields in farmers’ fields average from 1 to 2 t/ha in contrast to the higher yields of about 5 to 7 t/ha reported on breeding stations in the region (Fakorede et al. 2003).

Maize production in the savannas is faced with several production constraints which limit productivity. Poor soil fertility, drought, and Striga hermonthica parasitism combined can reduce on-farm yield by over 70% even with the use of high-yielding varieties. Land-use intensification in the northern Guinea savanna has resulted in serious land degradation and nutrient depletion (Oikeh et al. 2003). Nitrogen (N) is the nutrient most deficient in the soils and it most often limits maize yield (Carsky and Iwuafor 1995). Unfortunately, due to high cost and poor infrastructure, the availability of N fertilizers is limited.

The problem of poor soil fertility in the Guinea savanna is compounded by recurrent drought at various stages of crop growth. For maize, drought at the flowering and grain-filling stages can cause serious yield losses (Grant et al. 1989). This indicates that farmers’ fields are rarely characterized by only one biotic stress. It would, therefore, be desirable to increase the tolerance of crops to several stresses that occur in the target environment (Bañziger et al. 1999).

Maize plants infested by the parasitic weed<em/> Striga. Source: <i>icipe</i>
Maize plants infested by the parasitic weed Striga. Source: icipe

Surveys in the northern Guinea and Sudan savannas of Nigeria showed that Striga has remained a serious problem, attacking millet, sorghum, maize, and upland rice (Showemimo et al. 2002). In northern Nigeria, over 85% of fields planted to maize and sorghum were found to be infested (Dugje et al. 2006). Grain yield losses ranged from 10 to 100% for these crops (Oikeh et al. 1996). In addition to the damage from parasitic weeds, significant losses occur in maize if other weeds (grassy and broadleaf) are left to compete freely with the crop.

To maintain a good crop and increase grain yield/unit area, agronomic best practices should be undertaken to address these constraints. Appropriate soil fertility management, drought adaptation, and proper weed management can help to close the yield gap for maize in the West African savannas.

Soil fertility management
Maize is a heavy feeder particularly in terms of mineral N. Because soils in the West African savannas are low in plant nutrients, the crop cannot be grown without the application of some form of mineral and/or organic inputs. Farmers often see a dramatic increase in the response of maize to mineral N. If the fertilizer is applied wrongly, however, use efficiency will be reduced and the benefit will be minimal. For optimum economic yield, we recommend 50 kg/ha each of N, P, and K in the form of NPK 15:15:15 at planting if moisture is sufficient or at one week after planting (WAP), and 50 kg N/ha in the form of urea at 3–4 WAP. Increased use of organic and mineral fertilizers, together with diversification in cropping to include legumes grown in rotation is an important tool in restoring or sustaining soil fertility of the intensifying cropping systems of the dry savannas (Sanginga et al. 2003).

These so-called “balanced nutrient management systems” can be further enhanced through the use of improved cultivars that are drought tolerant and can use available nutrients efficiently, such as maize cultivars developed at IITA. This approach that has come to be known as integrated soil fertility management (ISFM) is not characterized by unique field practices, but is a fresh approach to combining available technologies in ways that preserve soil quality while promoting its productivity (Sanginga et al. 2003).

Agronomic practices for drought adaptation
Agronomic practices that enable farmers to adapt to the effect of mid- and end-of-season drought will increase maize productivity in the West African savannas. Several strategies have been developed for the conservation of soil and water to maintain productivity including rainwater harvesting, live barriers, supplementary irrigation, minimum tillage, mulching, bunded basins, and tree planting (Drechsel et al. 2004).

A central approach to increasing crop production in the dry savannas is the planting of well-adapted cultivars at the optimum date. The short growing season and frequent droughts require early and extra-early maturing crop cultivars with drought tolerance. Late- and medium-maturing cultivars, should also be drought tolerant and planted by mid-June after the rains have established. Breeders at IITA and partner institutions have developed cultivars that are early maturing, tolerant of drought, high temperatures, and low contents of soil nutrients and resistant to pests and diseases. These early maturing cultivars can be planted between mid-June and 25 July in the Guinea savannas and between the first week of July and mid-July in the Sudan savanna.

<em/>Striga management technologies. Source: <i>icipe</i>
Striga management technologies. Source: icipe

Weed management
Different approaches are recommended in managing parasitic weeds on the one hand and grassy and broadleaf weeds on the other. An integrated approach is recommended for the control of parasitic weeds. Because Striga attacks the plant underground and causes damage before emergence on the host, the use of postemergence herbicides and hand pulling cannot be recommended. Damage in maize can be reduced by growing varieties that are tolerant of or resistant to Striga or by planting trap crops such as varieties of groundnut (Arachis hypogaea), soybean (Glycine max), cowpea (Vigna unguiculata), and sesame (Sesamum indicum) that stimulate the Striga seeds to germinate without providing a viable host (Carsky et al. 2000).

Some studies have shown that applying N fertilizer reduces Striga emergence and numbers, and boosts cereal grain yield (Showemimo et al. 2002; Kamara et al. 2009). Applying N fertilizer may not be feasible as a stand-alone solution to managing Striga in maize because of the high cost but the combined use of N fertilizer and Striga-tolerant/resistant varieties has shown promise in the West African savannas (Showemimo et al. 2002; Kamara et al. 2009). However, control is most effective if a range of practices is combined into a program of integrated Striga control (ISC) that can provide sustainable control over a wide range of biophysical and socioeconomic environments. Ellis-Jones et al. (2004) showed that growing Striga-resistant maize after a soybean trap crop more than doubled economic returns compared with continuous cropping with local (nonresistant) maize. Kamara et al. (2008) showed that these practices reduced Striga infestation and damage on farmers’ fields and increased productivity by more than 200%.

Although manual weeding is an age-old practice in West Africa, it is no longer sustainable because of high labor costs and the aging farming population. Judicious use of herbicides is recommended to control weeds effectively and increase maize productivity. We normally recommend the use of postemergence herbicides to kill weeds before land preparation and planting. Two common types are Glyphosate and Paraquat. Glyphosate (Round-up, Glycel, Force-up) is usually strictly applied before planting, whereas Paraquat (Gramazone) can be mixed with Pendimenthalin (Stomp, Pendilin) and applied immediately after planting. Paraquat kills any live weeds in the field; Pendimenthalin kills preemerging weeds.

Berner, D.K., M.D. Winslow, A.E. Awad, K.F. Cardwell, D.R. Mohan Raj, and S.K. Kim. 1997. Sustainable control of S. hermonthica spp. through a focused integrated pest management programme. Pages 1–11 in: Contributing to food self-sufficiency: maize research and development in West and Central Africa, edited by B. Badu-Apraku, M.O. Akoroda, M. Oudraogo, and F.M. Quin. IITA, Ibadan, Nigeria.
Banziger, M., G.O. Edmeades, and H.R. Lafitte. 1999. Selection for drought tolerance increases maize yields across a range of nitrogen levels. Crop Science 39(4): 1035–1040.
Carsky, R.J., D.K. Berner, B.D. Oyewole, K. Dashiell, and S. Schulz. 2000. Reduction of Striga hermonthica parasitism on maize using soybean rotation. International Journal of Pest Management 46: 115–120.
Carsky, R.J, and E.N.O. Iwuafor. 1995.  Contribution of soil fertility research and maintenance to improved maize production and productivity in sub-Saharan Africa. In: Proceedings of Regional Maize Workshop, 29 May–2 June 1995, IITA, Cotonou, Benin Republic
Drechsel, P., A. Olaleye, A. Adeoti, L. Thiombiano, B. Barry and K. Vohland. 2004. Adoption driver and constraints of resource conservation technologies in sub-Saharan Africa. Available at
Dugje, I.Y., A.Y. Kamara, and L.O. Omoigui. 2006. Infestation of crop fields by Striga species in the savanna zones of northeast Nigeria. Agriculture, Ecosystems and  Environment 116: 251–254.
Ellis-Jones, J., S. Schulz, B. Douthwaite, M.A. Hussaini, B.D. Oyewole, A.S. Olanrewaju, and R. White. 2004. An assessment of integrated Striga hermonthica control and early adoption by farmers in northern Nigeria. Experimental Agriculture 40: 353–368.
Kamara, A.Y., A. Menkir, S.O. Ajala, and I. Kureh I. 2005. Performance of diverse maize genotypes under nitrogen deficiency stress in the northern Guinea savanna of Nigeria. Experimental Agriculture 41(2): 199–212.
Kamara, A.Y., F. Ekeleme, A. Menkir, D. Chikoye, and L.O. Omoigui. 2009. Influence of nitrogen fertilization on the performance of early and late-maturing maize cultivars under natural infestation with Striga hermonthica. Archives of Agronomy and Soil Science 55(2):125–145.
Kamara, A.Y.,  J. Ellis-Jones, P. Amaza, F. Ekeleme, A. Menkir, L. Omoigui, I.Y. Dugje, and N. Kamai. 2008. A participatory approach to increasing productivity of maize through Striga hermonthica control in northeast Nigeria. Experimental Agriculture 44 (3):349–364.
Kassam, A., E. Kueneman, B. Kebe, S. Ouedraogo, and A. Youdeowei. 2009. Enhancing Crop-Livestock Systems in Conservation Agriculture for Sustainable Production Intensification: A Farmer Discovery Process going to Scale in Burkina Faso. Integrated Crop Management 7. FAO, Rome, Italy.
Menkir, A., B. Badu-Apraku, S. Ajala, A.Y. Kamara, and A. Ndiaye. 2009. Performance evaluation of early-maturing maize landraces and improved varieties under contrasting moisture supply. Plant Genetic Resources: Characterization and Utilization 7(3): 205–215.
Oikeh, S.O. 1996. Dynamics of soil nitrogen in cereal-based cropping systems in the Nigerian Savanna. Ph.D. dissertation, Ahmadu Bello University, Zaria. Nigeria.
Oikeh, S.O., R.J. Carsky, J.G. Kling, V.O. Chude, and W.J. Horst. 2003. Differential N uptake by maize cultivars and soil nitrate dynamics under N fertilization in West Africa. Agriculture, Ecosystems and  Environment 100: 181–191.
Oikeh, S.O., V.O. Chude, G.J. Kling, and W.J. Horst. 2007. Comparative productivity of nitrogen-use efficient and nitrogen-inefficient maize cultivars and traditional grain sorghum in the moist savanna of West Africa. African Journal of Agricultural Research 2(3): 112–118.
Sanginga, N., K. Dashiell, J. Diels, B. Vanlauwe, O. Lyasse, R.J. Carsky, S. Tarawali, B. Asafo-Adjei, A. Menkir, S. Schulz, B.B. Singh, D. Chikoye, D. Keatinge, and Rodomiro Ortiz. 2003. Sustainable resource management coupled with resilient germplasm to provide new intensive cereal–grain legume–livestock systems in the dry savanna. Agriculture, Ecosystems and Environment 100: 305–314.
Showemimo, F.A., C.A. Kimbeng, and S.O. Alabi. 2002. Genotype response of sorghum cultivars to nitrogen fertilization in the control of Striga hermonthica. Crop Protection 21: 867–870.

ISFM for banana systems

Piet van Asten,, Severine Delstanche, Lydia Wairegi, Tony Muliele, Syldie Bizimana, Godfrey Taulia, Ken Giller, Peter Leffelaar, Laurence Jassogne, Philippe Baret, and Charles Bielders

Banana systems in Rwanda. Photo by Piet van Asten
Banana systems in Rwanda. Photo by Piet van Asten

Banana is the primary food crop in the Great Lakes Region, providing food and income for over 85% of the population. Unfortunately, current banana yields of 5–30 t/ha/year are low compared to potential yields of over 70 t/ha/year. Although between 25% and 70% of this yield gap can be explained by low soil fertility (Fig. 1), the use of external inputs such as fertilizers is virtually nonexistent and soil fertility is mostly managed by recycling local organic residues.

A study done by Severine Delstanche at the Catholic University of Louvain-la-Neuve (UCL) showed that very little nutrients were released from the soil through weathering of the soil minerals (Fig. 2). Hence, soil fertility depended almost entirely on the soil’s organic matter content. In banana-based farming systems, nutrient recycling is very important, as the harvest index is relatively small (<30%). This helps maintain relatively high organic matter content in the soil.

Figure 1. Primary crop constraints identified by use of boundary line approach.
Figure 1. Primary crop constraints identified by use of boundary line approach.

Furthermore, the large and perennial canopy and root system of banana help protect the soil from erosion. Banana therefore plays an important role in protecting the environment in this hilly landscape.

In addition to being an important component in sustaining soil fertility, banana plays an important socioeconomic buffer role for the smallholders. The crop provides food security as bunches are harvested throughout the year and any surplus can be sold to generate a continuous cash flow.

Banana systems particularly occur in areas with high population pressure and small (<2 ha) farm sizes. A study by Lydia Wairegi at Makerere University (Uganda), showed that fertilizer use was very profitable in the peri-urban area close to Kampala with marginal rates of return sometimes exceeding 500%. However, in areas far from the market (>150 km), the intensification process seemed less promising, but banana continues to play an important buffer role to maintain food security and protect the environment. In these remote locations, it seems wiser to invest in improved use of local (nutrient) resources, than to purchase mineral fertilizers.

Figure 2. The proportion of annual K fluxes in banana systems originating from soil mineral weathering (2%), crop<br /> residues (77%), and the crop harvest (21%).
Figure 2. The proportion of annual K fluxes in banana systems originating from soil mineral weathering.

To maintain its buffer role, banana can be integrated with other crops such as coffee and beans. The Ph.D. studies of Tony Muliele and Syldie Bizimana (both UCL) showed that intercropping beans with banana could be improved. Traditionally, farmers in Rwanda, Burundi, and DR Congo would till the banana field at the beginning of the wet season to suppress weeds and prepare the land for bean intercropping. Unfortunately, this practice damages a large proportion of the superficial root system of banana plants. Based on practices observed in Southwest Uganda, a technology of zero-tillage and mulching was tested. Beans are planted in the mulch. The planting holes for the beans were made using a stick. The use of external mulch greatly improved banana performance in eight trials across the region. However, beans did suffer some setback in some instances when the improved banana growth would lead to a more dense canopy, outshading the understory beans. In collaboration with Bioversity International and the Tropical Soil Biology and Fertility Institute of CIAT (TSBF-CIAT), a series of trials was conducted to reduce the banana canopy through leaf pruning. The results are almost ready, but they provide farmers with advice on how to best manage the trade-offs between banana and the understory legumes.

To improve fertilizer use efficiency and profitability, it will be important for farmers to apply the right nutrients at appropriate rates. To enable the identification of the most deficient nutrients (see photo) that need primary attention when applying fertilizers, compositional nutrient diagnosis (CND norms) were developed by Lydia Wairegi in Uganda and by Severine Delstanche in Rwanda. The CND norms are based on foliar analysis and allow a quick assessment of nutrient deficiencies observed within the plant. Contrary to critical norms for single nutrients, the CND allows for an integrated assessment of nutrient imbalances within the plant.

Farmers can use pictures to diagnose nutrient deficiencies for nitrogen, phosphorus, potassium, and magnesium.
Farmers can use pictures to diagnose nutrient deficiencies for nitrogen, phosphorus, potassium, and magnesium.

Besides developing fertilizer recommendations based on foliar analysis, IITA conducted a series of large nutrient omission trials in central and southwest Uganda. Based on the quantification of nutrient uptake, soil nutrient supply, and crop response, a QUEFTS model was developed to predict fertilizer requirements in collaboration with Wageningen University (WUR). This work was led by Ph.D. student Kenneth Nyombi and is currently being carried forward by Ph.D. student Godfrey Taulya. He observed that potassium nutrition was particularly important for banana to alleviate drought stress. The result from the ongoing research effort clearly shows that strong synergies can be achieved when integrating soil fertility, agronomic, and economic research approaches at the plot, farm, and regional levels.

NRM in cassava and yam production systems

Stefan Hauser,

Cassava has the potential to produce roots even under poor soil conditions. Photo by IITA
Cassava has the potential to produce roots even under poor soil conditions. Photo by IITA

Why are yields of cassava in Thailand and India three times higher than in Africa and production costs in Brazil only one-third of those here? Although Africa suffered from the Cassava Mosaic Disease pandemic and currently faces the threat of Cassava Brown Streak Disease, breeding tolerant and resistant germplasm has contributed to yield gains over the last three decades. Thailand, India, and Brazil have been successful in commercial cassava production with yields between 25 and 40 t/ha. The question arises: how can African farmers realize more of the >80 t/ha yield potential of cassava?

Natural resource management (NRM), agronomy, and crop husbandry have hardly ever been credited with “breakthrough” solutions to hunger and poverty. However, when more than 50-75% of the cassava yield potential is not being realized, major improvements are clearly possible through NRM, agronomy, and appropriate crop husbandry.

Agronomy and crop husbandry
For West Africa there is still a dearth of agronomic information on cassava. Currently a density of 10,000 plants/ha is the standard, while further increases are being recommended without concrete data on the yield responses to increased density by different growth types. Cassava varieties vary widely in their branching height and level of ramification, leading to different levels of ground cover by single plants and of the start and intensity of intra-specific competition. Cassava yield distribution within the same variety is highly biased (Fig. 1), raising questions on the optimum plant density and issues such as genetic uniformity and crop responses to edaphic (soil) factors.

Figure 1. Relative contribution to yield of individual plants of cassava variety Zizila in DRC.
Figure 1. Relative contribution to yield of individual plants of cassava variety Zizila in DRC.

One future effort will be to determine optimum plant densities for monocrops by major cassava growth types.

Intercropping cassava with maize or grain legumes is still widely practiced and needs to be improved. The short-term intercrops are cleared from the field, leaving space unused that can be invaded by weeds, thus there needs to be a follow-up either with weed control or a second crop to occupy the open space. Various crops will be tested for their capacity to perform between developed cassava plants and their contribution to total system productivity.

Weed control remains a problem as there are no postemergence herbicides that cassava would tolerate. Combinations of preemergence herbicides with appropriate planting techniques have the potential to reduce weed competition and labor. For instance, a preemergence herbicide can be applied before planting cassava. The herbicide kills germinating seeds as they break through the herbicide-sealed soil surface. The cassava stakes need to be planted in a vertical position and the orientation needs to be correct so that no emerging cassava leaves touch the soil surface. Such technologies combined with the follow-up use of postemergence herbicides with shields can drastically reduce labor and increase productivity as weeding can be done at the most efficient time.

Fertilizer use is low in Africa yet it appears certain that fertilizer or other forms of soil nutrient replenishment can contribute to yield increases, higher farm incomes, possibly to lower consumer prices, and thus to better livelihoods. Using average nutrient uptake into all cassava plant parts (dry matter basis) of 6.2 kg N/t, 1 kg P/t, and 5.3 kg K/t, a total supply of 165–25–145 kg N-P-K/ha is required to attain 50% of the current potential yield (45 t/ha fresh roots). Such amounts are unlikely to be supplied by the soil and thus nutrient supply is a crucial factor in achieving higher cassava yields.

There are no recent fertilizer response curves for cassava and yam in West Africa, hence, farmers do not know the composition and amounts of fertilizer to apply. The nutrient(s) most limiting to cassava production have not been quantitatively determined. The replenishment of any most limiting nutrient would lead to substantial yield increases. Depending on the limiting nutrient, productivity and profitability increases may be possible at a very low cost and risk. IITA uses a stepwise approach, first determining the most limiting nutrient(s) followed by elaborating the optimum quantity required and the construction of recommendations for optimal nutrient composition and quantities. IITA is currently working with the International Fertilizer Development Center on testing special fertilizer blends for cassava, addressing the augmentation of neglected nutrients such as sulfur, magnesium, zinc, and boron.

Use of other nutrient sources
Compost, manure, mulch, and rock phosphate have all been proposed as means to improve soil nutrient status and crop production. However, none of these sources has had a major impact as farmers need land to produce biomass or else infrastructure is required to mine, process, and distribute rock phosphate. Although the biological sources are important, constraints in biomass production need to be overcome first.

Figure 2. Crop yield response to planted herbaceous fallow in West and Central Africa.
Figure 2. Crop yield response to planted herbaceous fallow in West and Central Africa.

Mineral fertilizers alone cannot sustain crop production on degraded land. Soil organic matter and  soil micro-, meso-, and macro-fauna are important in maintaining soil quality and health. Traditionally, fallow phases between crops were replenishing the soils’ production capacity. With increased population densities, fallow phases have been shortened or no longer exist. Thus, soils do not recover but continue to lose their production potential. Farmers do not seem to invest in soil fertility but look for ways of coping with ever less fertile soils, thereby degrading them to a stage where cropping becomes unprofitable.

Such situations have been encountered in southern Bénin. Soil fertility and quality management techniques, such as cover crops, manure application, or any other form of organic matter and nutrient recycling have not been adopted at larger scales. In retrospect, there have been constraints to the adoption that were not considered in the process of technological development. Today, with more options available and a stronger and earlier involvement of farmers in research for development, such approaches are worth reconsidering. One such technology, using leguminous cover crops, had little if any success in cassava (Fig. 2).

Controlling the cover crop was a major problem. Consequently IITA works today on efficient and effective control methods. Pueraria phaseoloides was introduced to smallholders in southern Cameroon but it was not readily accepted as farmers immediately identified it as an aggressive weed, able to destroy crops. However, two years into the use of Pueraria, fallow farmers noticed that the weeds most difficult to control had disappeared and that it was easier to clear Pueraria than the natural fallow. Some farmers burned the Pueraria only to find the land ready to crop without major labor input. Yields of cassava, maize, and groundnut were generally higher after Pueraria, whereby the labor-saving burning produced the highest yields (Fig. 3).

Figure 3. Cassava fresh root yield in burned and mulched maize-cassava and burned maize-cassava-groundnut intercrop.
Figure 3. Cassava fresh root yield in burned and mulched maize-cassava and burned maize-cassava-groundnut intercrop.

Considering farmers’ needs
Pueraria was introduced for soil fertility replenishment but was adopted for its labor-saving effects. Soil fertility was not perceived as a problem and thus positive effects on the soil could be compromised (by burning) without compromising yields. Effects such as weed suppression and the reduction of soil-borne pests and diseases may contribute to the yield increases after Pueraria.

Livestock integration and the search for synergies
Few farmers adopted the use of green manures for soil fertility improvement because they have no direct benefits from it. Herbaceous legumes have rarely been used to feed livestock, although there is (anecdotal) evidence that livestock feed on them and that they are beneficial to growth and reproduction. In the IITA-led CRP on Humidtropics, livestock integration will be a major aspect. It will add value to green manure species when these are used to feed livestock that will also benefit from the canopies of root and tuber crops (cassava leaves) remaining at root harvest. Thus, there will be an increase in returns of animal manure to fields, and to crop yields through the combined use of green and animal manures for improved food security and farm incomes.

Efficient combinations of agronomic practices, nutrient supply, and soil management practices will be developed to increase the productivity of cassava and yam while improving the status of the natural resource base. Synergistic effects between these measures and the integration of livestock or fish farming will increase resource use efficiency and income generation as well as the quality of the farm food supplies. Due consideration of social and gender aspects in farm household operations will identify the entry point best suited for IITA’s interventions. Farmers’ feedback and innovations will be integrated into approaches on sustainable intensification to increase food production and improve rural livelihoods while enhancing the capacity of the agroecosystems to deliver essential services.

Hauser, S. and C. Nolte. 2002. Biomass production and N fixation of five Mucuna pruriens varieties and their effect on maize yields in the forest zone of Cameroon. Journal of Plant Nutrition and Soil Science 165: 101–109.
Hauser, S., C. Nolte, and R.J. Carsky. 2006. What role can planted fallows play in humid and sub-humid West Africa? Nutrient Cycling in Agroecosystems 76: 297–318.

Boosting the productivity of cassava-based systems in DR Congo

Bernard Vanlauwe,, Patrick Mutuo, Nzola Mahungu, and Pieter Pypers

The intensification of African agriculture is an essential response to the increasing demands for more food without endangering important natural resources, including the forests in the Congo basin.

Because of its potential to produce some roots, cassava is often considered a crop that “likes” poor soils but, as all other crops, it responds to and requires a sufficient amount of nutrients to produce attainable yields. The transformation of cassava from a food security to a cash crop in many countries in Africa further stresses the need for nutrient replenishment strategies in cassava-based systems since the transport of cassava roots to processing plants can accelerate the amount of nutrients exported from the farm.

In recent years, integrated soil fertility management (ISFM) (see article by Vanlauwe et al. this publication) has been accepted by many organizations as the underlying technical framework for the sustainable intensification of smallholder systems in Africa. This article highlights the progress of work on the application of ISFM principles in the context of cassava-based systems in DR Congo.

In DR Congo application of 2 bags of NPK fertilizer per hectare results in root yield increases from 30% to 160%.
In DR Congo application of 2 bags of NPK fertilizer per hectare results in root yield increases from 30% to 160%.

Current situation
In the highlands of Sud-Kivu province, cassava and common beans are among the main food crops traditionally cultivated in mixed cropping systems. Cassava monocropping is done only in marginal fields where other crops fail to yield. Farmers generally allocate about 0.2–0.3 ha (30–45% of their farm area) to cassava–legume intercropping and obtain average yields of 400–800 kg/ha of legume grains and 10–15 t/ha of cassava fresh roots. Pressure on land is very heavy due to high population densities and justifies agricultural intensification and investment in soil productivity.

In Bas-Congo province, on the other hand, farmers practice slash-and-burn agriculture. Cassava is grown for 1 or 2 years, followed by fallow periods of 2 to 4 years. In the past two decennia, the population has grown by more than 50% leading to more demands for food, especially from nearby Kinshasa. Improved and sustainable, fire-free production systems are urgently needed. In DR Congo, most farmers have no access to improved varieties and have very limited options to improve soil fertility.

Fertilizer and germplasm
First, the use of improved, pest-and disease-resistant varieties in combination with appropriate rates of NPK fertilizer was observed to result in a 30–160% increase in cassava root yields in eastern DR Congo. A visible increase was observed in yields of the stems, important for the production of planting material (see photo). In western DR Congo, cassava yields doubled from 12 to 25 t/ha with the application of moderate rates of NPK and reached over 40 t/ha with higher rates. Several initiatives are taking place to ensure that large quantities of planting materials reach smallholder farmers with specific attention being given to those varieties resistant to cassava mosaic disease and the brown streak virus.

Figure 1. Cassava storage root yields as affected by application of compound fertilizer (17 nitrogen: 17 phosphorus: 17 potassium) at rates of 0 (F0), 40 (F1), 120 (F2), and 200 (F3) kg K/ha, and green manure (TI = <em/>Tithonia sp.; CH = <i>Chromolaena </i>sp.) at 2.5 t dry matter/ha alone or together with compound fertilizer at 40 kg K/ha in two trial locations in Bas-Congo, DRC. SED: standard error of difference at P<0.05. Source: Adapted from Pypers et al. 2012
Figure 1. Cassava storage root yields as affected by application of compound fertilizer (17 nitrogen: 17 phosphorus: 17 potassium) at rates of 0 (F0), 40 (F1), 120 (F2), and 200 (F3) kg K/ha, and green manure (TI = Tithonia sp.; CH = Chromolaena sp.) at 2.5 t dry matter/ha alone or together with compound fertilizer at 40 kg K/ha in two trial locations in Bas-Congo, DRC. SED: standard error of difference at P<0.05. Source: Adapted from Pypers et al. 2012

Combined application of fertilizer and organic inputs
Fertilizer response and the effect of combining inorganic and organic nutrient resources were also evaluated on cassava systems. The most common fertilizer, NPK 17:17:17, was applied in western DR Congo with or without green manure made from Tithonia sp. or Chromolaena sp., and the effects on storage root yield were evaluated in two locations with a differing soil fertility status (Fig. 1). Both plants are commonly found in fallow vegetation in western DR Congo. Control yields were similar at the two sites (12 t/ha), but the response to fertilizer differed between the sites: storage root yields reached 40 t/ha at Kiduma but only 20 t/ha at Mbuela with the addition of 200 kg K/ha. A much larger response to Tithonia sp. green manure was also observed at Kiduma, which was likely to have been related to the higher quality and nutrient contents of the green manure grown at that site.

Combining organic and inorganic nutrient resources did not result in positive interactions. No significant differences were observed between the yields after the sole application of either fertilizer or green manure to the control and those obtained with the combined application of both nutrient sources (Pypers et al. 2012). In maize-based systems, positive interactions between organic and inorganic fertilizers often arise from better synchrony in N release and N uptake by the crop. In cassava systems, where K is more often the most limiting nutrient, such a mechanism is likely to be less relevant.

In the highlands of eastern DRC alternative spacing of cassava  (2 × 0.5 m instead of 1 × 1 m) allows integration of four lines of legumes during one season and two lines of legumes during the second season without affecting cassava densities and yields.
In the highlands of eastern DRC alternative spacing of cassava (2 × 0.5 m instead of 1 × 1 m) allows integration of four lines of legumes during one season and two lines of legumes during the second season without affecting cassava densities and yields.

In eastern DR Congo, the use of improved germplasm did not result in yield increases without the simultaneous implementation of other ISFM components. Modifying the crop arrangement by planting cassava at 2 m between rows and 0.5 m within the row, intercropped with four legume lines, increased bean yields during the first season and permitted a second bean intercrop. This can also increase the total legume production by up to 1 t/ha and resulted in additional revenues of almost $1000/ha (see photo). The crop arrangement or a second legume intercrop did not affect cassava root yields. Fertilizer application increased both legume and cassava yields, and net revenue by $400–700/ha with a marginal rate of return of 1.6–2.7. Replacing the common bean intercrop by groundnut increased net revenue by $200–400/ha, partly because of the higher market value of the grains, but mostly due to a positive effect on yield of cassava storage roots. Soybean affected cassava yields negatively because of its high biomass production and long maturity period; modifications are needed to integrate a soybean intercrop into the system.

Local adaptation
Due to the high variability in soil fertility status, the varying landscape features, and the variation in access to inputs, local adaptation is required to ensure that the investments made by cassava-producing households  result in the highest returns, in line with the resources (e.g., cash, land, labor) that these households have (see photo). Such adaptation efforts are best led by extension and development partners that have the required skills and capacity to implement such efforts at scale. In eastern DR Congo, erosion is the most urgent issue to be tackled to enhance the sustainability of cassava-based systems. Results from Southeast Asia with the use of live hedges should be explored for these environments.

Cassava land preparation varies widely in DRC partly affected by slope and water status of the land.
Cassava land preparation varies widely in DRC partly affected by slope and water status of the land.

These findings demonstrate the large potential of ISFM to increase productivity in cassava–legume systems in DR Congo. This is crucial in view of the fact that cassava is changing from being almost only a food security crop to one for which there is high demand in local and urban markets. The intensification of production is thus a prerequisite for sustaining cassava-producing households and ISFM can assist in achieving such benefits. However, these benefits were not observed in all study sites. In poor soils, productivity increases were variable or absent, and soil amendments are required. Better targeting and local adaptation of the technologies are possible with a better understanding of the conditions under which positive effects occur.

Pypers, P., J.M. Sanginga, K. Bishikwabo, M. Walangululu, and B. Vanlauwe. 2011. Increased productivity through integrated soil fertility management in cassava–legume intercropping systems in the highlands of Sud-Kivu, DR Congo. Field Crops Research 120: 76–85.
Pypers, P., W. Bimponda, J.P. Lodi-Lama, B. Lele, R. Mulumba, C. Kachaka, P. Boeckx, R. Merckx, and B. Vanlauwe. 2012. Combining mineral fertilizer and green manure for increased, profitable cassava production. Agronomy Journal, in press.

Cassava improvement in the era of “agrigenomics”

Ismail Yusuf Rabbi (, Melaku Gedil, Morag Ferguson, and Peter Kulakow
I. Rabbi, Postdoctoral Fellow (Molecular Genetics); M. Gedil, Head, Bioscience Center, IITA, Ibadan, Nigeria; M. Ferguson, Molecular Geneticist, IITA, Nairobi, Kenya; and P. Kulakow, Cassava Breeder, IITA, Ibadan, Nigeria

Pro-vitamin A 'yellow root' cassava developed by the IITA cassava breeding program. Photo by IITA.
Pro-vitamin A 'yellow root' cassava developed by the IITA cassava breeding program. Photo by IITA.

In the last 45 years, IITA has played a pivotal role in the genetic improvement of cassava for resource-poor farmers in sub-Saharan Africa (SSA). More than 400 cassava varieties have been developed that are not only high yielding but also resistant to diseases and pests. Many of these improved varieties have been extensively deployed in SSA and have helped to avert humanitarian crises caused by the viral disease pandemics that devastated local landraces in East and Central Africa. The cassava breeding program in Ibadan has a collection of more than 750 elite cassava clones representing current and historical materials accumulated over the last 45 years. These materials, referred to as the genetic gain collection (GGC), are accompanied by extensive field evaluation (phenotypic) data. In addition, the active breeding collection contains over 1000 African landraces and more than 400 new advanced breeding clones that are also accompanied by phenotypic data, including observations of disease and pest resistance, plant architecture, flowering ability, and performance in storage root yield. The most recent success of the conventional cassava breeding program culminated in the release of three vitamin A cassava varieties by the Government of Nigeria. These varieties (IITA TMS I011368, IITA TMS I011371, and IITA TMS I011412) were first cloned from seedlings in Ibadan in 2001 and have been subjected to extensive field testing throughout Nigeria. While almost all cassava in Nigeria are currently white fleshed, vitamin A cassava produces yellow-fleshed roots with nutritionally significant concentrations of carotenoids that produce vitamin A in the human body when consumed as yellow gari or fufu. In cooperation with HarvestPlus, IITA and partners will distribute vitamin A cassava planting materials to more than 25,000 farmers in 2013. New yellow-fleshed genotypes in the pipeline promise continued improvement in pro-vitamin A content, yield, and dry matter in the coming years.

Preparation of cassava DNA for genotyping by sequencing. Photo by IITA.
Preparation of cassava DNA for genotyping by sequencing. Photo by IITA.

As the vitamin A cassava illustrates, the genetic improvement of cassava has mostly been achieved through conventional breeding methods based on phenotypic selection. The only known direct application of molecular markers in cassava breeding is selection for resistance to cassava mosaic disease and cassava green mite. Recent advances and a reduction in the cost of the next-generation sequencing technologies now promise to usher in a new era for cassava breeding that will combine the success of conventional hybridization, selection, and multilocational yield trials with the latest advances in genomic resources.

Setting the stage for “next-generation cassava breeding”
Cognizant of the potential of marker technologies to improve the efficiency and effectiveness of cassava breeding, IITA, in collaboration with partners, embarked on the development and deployment of molecular markers1. With the recent accumulation of genomic resources in cassava research, including the first full cassava genome sequence2, our emphasis at IITA has shifted towards the application of these resources in molecular breeding3. One recent achievement is the identification and validation of nearly 1500 single nucleotide polymorphism (SNP) markers through an international collaboration led by IITA’s geneticist, Morag Ferguson4. These SNPs have been converted to a highly parallel hybridization-based genotyping system that has been shared with the international cassava research community through partnership with the Generation Challenge Program (GCP).

An example of an SNP genotyping data plotted with KBioscience’s SNPviewer software. Inset: raw SNP genotyping data from Illumina’s GoldenGate®assay.
An example of an SNP genotyping data plotted with KBioscience’s SNPviewer software. Inset: raw SNP genotyping data from Illumina’s GoldenGate®assay.

In addition, the first SNP-based genetic linkage map of cassava has been developed by IITA in collaboration with Heneriko Kulembeka of the Agricultural Research Institute (ARI), Ukiriguru, Tanzania. A linkage map is analogous to landmarks (SNP markers in this case) placed along chromosomes that guide researchers to genes or genomic regions controlling traits of interest. Such a linkage map is an indispensable tool for marker-assisted selection (MAS). SNP and SSR markers have also been applied to uncover quantitative trait loci (QTL) associated with resistance to cassava brown streak disease (CBSD)―which is ravaging cassava production in Eastern and Southern Africa―in a collaboration between IITA, CIAT, and ARI-Tanzania. Another dramatic development in cassava genomics is the recently completed sequencing of the cassava genome through the partnership of the US Department of Energy’s Joint Genome Institute and 454 Life Sciences2.

The progress in next- generation technologies has drastically reduced the costs of DNA sequencing so that genotyping-by-sequencing (GBS) is now feasible for species such as cassava, ushering in a new era of agricultural genomics5. This will revolutionize the application of genomic tools for cassava improvement. GBS involves the cutting of genomic DNA into short pieces at specific locations using a restriction enzyme. The ends of these pieces are sequenced using techniques that allow sequencing of many samples at the same time. The beauty of this method is the use of adaptors containing barcodes (unique tags) that are enzymatically joined to the digested DNA fragments, enabling simultaneous sequencing or multiplexing of up to 384 samples in one sequencing reaction. This economy of scale greatly reduces the cost of processing each individual DNA to less than $10/sample. Approximately 200,000 markers can be identified and mapped in a very short time. With this powerful tool, breeders may conduct genomics-based research that was inconceivable a couple of years ago. Some of the exciting new research applications include polymorphism discovery, high-density genotyping for QTL detection and fine mapping, genome-wide association studies, genomic selection, improving reference genome assembly, and kinship estimation.

High-density QTL mapping and fine mapping
In the past, a limitation for QTL mapping was the number of markers on a genetic linkage map. With new SNP-based technologies this is no longer a limitation. This allows for fine mapping of QTLs so long as a sufficient number of individuals in the mapping population can be developed. IITA, in collaboration with national partners [ARI-Tanzania and National Crops Resources Research Institute (NaCRRI), Uganda], is using SNPs to discover QTLs associated with sources of tolerance for CBSD.

Preparation of gari, the most popular food product from cassava. Photo by IITA.
Preparation of gari, the most popular food product from cassava. Photo by IITA.

The next frontier for cassava genomics
Using the genotyping by sequencing approach, scientists from IITA and Cornell University, USA, are currently genotyping more than 2000 accessions of cassava, including released varieties, advanced breeding lines, and landraces from Africa. This is a pilot study of genomic selection funded by the Bill & Melinda Gates Foundation to explore the potential for using the IITA breeding collection, including genetic gain, local germplasm, and current advanced breeding lines, as the base population to begin genomic selection for West Africa. The IITA breeding collection has been extensively characterized in many locations and over many years. The convergence of high-density SNP data and extensive phenotypic data in IITA’s cassava collection sets the stage for the implementation of genome-wide association studies (GWAS) and genomic selection (GS) in breeding. The aim of GWAS is to pinpoint the genetic polymorphisms underlying agriculturally important traits. In GWAS, the whole genome is scanned for significant marker-trait associations, using a sample of individuals from the germplasm collections, such as a breeder’s collection. This approach of “allele mining” overcomes the limitations of traditional gene mapping by (a) providing higher resolution, (b) uncovering more genetic variants from broad germplasm, and most importantly, (c) creating the possibility of exploiting historical phenotypic data for future advances in breeding cassava.

A schema of genomic selection (GS) processes, starting from phenotyping and genotyping of the training population and selection of parental candidates via genomic estimated breeding value (GEBV)–based selection. Note that selection model improvement can be performed iteratively as new penotype and marker data accumulate.
A schema of genomic selection (GS) processes, starting from phenotyping and genotyping of the training population and selection of parental candidates via genomic estimated breeding value (GEBV)–based selection. Note that selection model improvement can be performed iteratively as new penotype and marker data accumulate.

GS is a breeding strategy that seeks to predict phenotypes from high-density genotypic data alone, using a statistical model based on both phenotypic and genotypic information from a “training population”. For cassava, phenotyping is the slowest and most expensive phase of the crop’s breeding cycle because of the crop’s low multiplication ratio of between 5 and 10 cuttings/plant. Thus, it takes several cycles of propagation (up to 6 years) to carry out a proper multilocational field trial evaluation. The implementation of GS at the seedling stage should: (a) dramatically reduce the length of the breeding cycle, (b) increase the number/unit time of crosses and selections, and (c) increase the number of seedlings that could be accurately evaluated. The reduced breeding cycle means that the ”engine of evolution,” i.e., recombination and selection, can proceed at a rate that is three times as fast as phenotypic-based selection, while saving resources. In conclusion, cassava breeding in IITA is being redefined, thanks to the increasing availability and deployment of genomic resources. Combining these resources with IITA’s long-standing conventional breeding pipeline means that the best days of cassava improvement lie ahead. These efforts will ultimately satisfy the increasing need for more healthy and nutritious food produced in environmentally sustainable ways.

1 Lokko et al. 2007. Cassava. In: Kole et al (ed). Genome mapping and molecular breeding in plants, Vol. 3. Pulses, Sugar and Tuber Crops. Springer-Verlag Berlin Heidelberg.
2 Prochnik S., P.R. Marri,B. Desany, P.D. Rabinowicz, et al. 2011. Tropical Plant Biol. doi:10.1007/s12042-011-9088-z. 3 Ferguson M., I.Y. Rabbi, D-J.Kim, M. Gedil, L.A.B. Lopez-Lavalle, and E. Okogbenin. 2011a. Tropical Plant Biol. DOI 10.1007/s12042-011-9087-0.
4 Ferguson M.E., S.J. Hearne, T.J. Close, S. Wanamaker, W.A. Moskal, C.D. Town, J. de Young, P.R. Marri, I.Y. Rabbi, and E.P. de Villiers. 2011b. Theor Appl Genet. DOI: 10.1007/s00122-011-1739-9.
5 Elshire R., J. Glaubitz, Q. Sun, J. Poland, and K. Kawamoto. 2011. PLoS ONE 6:e19379.

Partnerships as relationships for agricultural development

Krishnamurthy Sriramesh (
Professor, College of Business, Massey University, Wellington, New Zealand

Humans and organizations have to depend on others for optimal existence to work effectively to achieve their goals. However, the significance of such interdependencies is often overlooked because of the tendency to take for granted partnerships, relationships, and communication in the organizational context. These key areas are often ignored, being labeled as “soft science”.

Building a coalition of public-public and public-private partnership for the promotion of 40% cassava flour in bread. Photo by IITA.
Building a coalition of public-public and public-private partnership for the promotion of 40% cassava flour in bread. Photo by IITA.
What is partnership?
In organizational contexts, the term “partnership” usually means the legal/contractual association between two or more entrepreneurs. The word “partner” originated from parcenter-‒a legal term meaning “joint heir.” In the fourteenth century, the emphasis on “partner” shifted away from this legal orientation because of the similarity to “part” (part of). Webster’s dictionary still puts the contractual relationship of the word partner first and only then mentions “a cooperative relationship between people or groups who agree to share responsibility for achieving some specific goal.” This nonlegal definition is most useful for discussing partnerships in agriculture for development. Using the term “partner” to refer to the various human elements involved in the long chain of agriculture for development helps us counter such conventional wisdom and assists in moving science closer to the common man.

Each partnership has three broad phases: initiation, management, and exit. Entering into a partnership, whether at the personal or the organizational level, should be done with care and a level of informed thinking that should include how the partnership will also be terminated. If partnerships are entered into in haste or without much groundwork, there is a high probability that they will lead to failures, and often result in loss of reputation as well. Especially when one does not have the luxury of time to assess potential partners, relying on previous experiences of working with a partner (and an assessment of the strengths and weaknesses of the partner) is a very good foundation with greater potential for success. Therefore, personal as well as institutional “memory” is crucial to success in choosing the right partner. So also is harnessing the strengths of a partner (while avoiding weaknesses) for maximum harmony and symbiosis.

Types of partnership
As relationships, three types of partnerships can be discerned: exchange, communal, and exploitive. An exchange relationship is one of pure barter where material or even information may be exchanged often among strangers as seen between a buyer and salesperson. Communal relationships often occur between partners who have known each other and thereby care for each other at a deeper level. The exchanges in a communal relationship can often be for altruistic purposes where one partner derives gratification by making the other happy, successful, comfortable, etc. Exploitive partnerships are indicative of parasitic tendencies from one partner often exploiting the goodness (kindness) of the other. Knowledge of the characteristics, strengths, and weaknesses of partners is vital to managing partnerships for increased harmony and efficacy.

Ingredients of good partnership
There are other key ingredients that help to develop/identify good partners. Foremost is the element of trust. Every good partnership is built on trust. When trust is lost, partners become suspicious to the point of being paranoid and that leads to a breakdown of the relationship. Transparency and open communication help to build trust. A reasonable argument can be made that it is impossible to build and maintain trust without effective (two-way) communication among partners. Mutuality of control (sharing control in the partnership) is another key ingredient of good partnerships. When control is not mutually shared, this often leads to exploitive partnerships and that is certainly not a healthy relationship.
Commitment is another key element of a good partnership. Every partnership is built around attaining certain goals and objectives. Unless every partner involved has adequate, or nearly equal, commitment to those goals and the ways by which to reach them, there can be no synergy in that partnership. Commitment to harmony within the partnership is equally vital and when both are present, a partnership is bound to flourish, leading to exponential outputs. Finally, satisfaction is a vital ingredient of a good partnership. Unless all partners are satisfied with the various elements of the partnership (process, output, and outcome), there is bound to be discord, ultimately leading to a breakdown in the partnership.

Considerations for good partnerships
There are several elements that help in cultivating good partnerships: (a) access: when partners share access to each other and their networks of information and influence, there is harmony in the partnership; (b) disclosure and openness: unless both partners are equally open, the more “closed” partner is more likely to exploit the openness of the more “open’ and sharing partner; (c) share mutual networks: good partners help one another’s integration into individual networks, thereby enhancing one another’s outreach and influence; (d) shared interests and shared tasks: overlapping interests obviously bring partners closer together whether in personal or professional settings; similarly, sharing similar tasks (and thereby goals and objectives) also leads to closer partnerships; and (e) continuing dialog: frequent communication between partners is a sure way of building good partnerships. In addition, dialog helps to reduce tensions in partnerships before these become irreparable.

Intra-organizational partnership matters
It is important for organizations to recognize that partners internal to the organization (employees) are just as, if not more, important than partners outside the organization. Internal partners are often taken for granted, a sure recipe for a weak organizational culture that breeds rumors, discord, and low morale. Involving internal stakeholders in governance is vitally important as it drives employees to feel they have invested in the organization and thereby elicits greater loyalty, commitment, and satisfaction in the partnership. Finally, it would not be hyperbole if one were to state that organizations neglect relationship building at their peril.

Partnership is a mission of IITA
IITA works in partnership with national, regional, and international research institutes, national governments, civil society organizations, and the private sector to conduct research and ensure that research results benefit agriculture growth and development, particularly in sub-Saharan Africa. During the course of 45 years, IITA has partnered with over 200 different organizations all around the world to advance pro-poor research programs. IITA recognizes that close collaboration with partner organizations is essential for the optimum use of resources, knowledge, technologies, access to cutting-edge science and technologies, mutual learning and for making a positive impact on the livelihoods of poor farmers.

Impact of cassava R4D on smallholder farmers

Does research-for-development (R4D) have an impact on small-scale farmers? The answer is a resounding ‘yes’ based on a series of impact studies on IITA’s cassava R4D work in the Democratic Republic of Congo (DRC) and Malawi.

Cassava harvest in Bungu, Tanzania. Photo by E. Kanju, IITA.
Cassava harvest. Photo by E. Kanju, IITA.

Democratic Republic of Congo
In DRC, an emergency response R4D program was implemented from 2001 to 2009 after the outbreak of the cassava mosaic disease. The study provided hard evidence of a clear impact on household access and participation in markets, adoption of improved crop varieties and crop management practices, plot yields, gross margins, and food security.

Cassava is the number one provider of staple food and wages in DRC, accounting for more than 70% of the annual crop area and supplying around 56% of the calories in the diet (FAO 2010). In 1996, a new, more virulent Ugandan strain of the East African Cassava Mosaic Virus (EACMV-Ug) was detected. By 2000, it had spread to most cassava-producing regions. Most of the widely planted varieties had no resistance to EACMV-Ug and it was feared that the disease would lead to widespread crop losses and food insecurity.

The emergency response program to the outbreak was started in 2001 and aimed at increasing farmers’ income, improving food security, and nutrition, and reducing poverty. It was supported through a multi-donor funding basket.

The first phase was implemented from 2001 to 2006 in the western provinces of Bas Congo, Kinshasa, and Bandundu because there was war in the eastern part of the country. The second phase, from 2007 to 2009, was expanded to include the central and eastern provinces: Equateur, Province Orientale, Katanga, Kasai Oriental, Kasai Occidental, Maniema, Nord-Kivu, and Sud-Kivu.

The first phase focused on the rehabilitation of cassava production through the multiplication and distribution of clean planting material of existing, already released cassava varieties, breeding for improved varieties with resistance to the viral disease and acceptable consumer traits, and improved crop management technologies. The second phase added components of postharvest management.

The program was implemented through an agricultural R4D approach which brought together different R4D organizations into public–private partnerships with clearly defined roles. These included the Programme National Manioc (PRONAM) within the Institut National pour l’Etude et la Recherche Agronomiques (INERA), IITA, the South-East Consortium for International Development (SECID), FAO, Centre d’Appui pour le Développement Integral de Mbankana (CADIM), PACT Congo, community based organizations, farmers’ associations, and village-level farmers’ groups.

Chikwangues, made from fermented and pounded cassava, for sale at Kolo market, Bas-Congo, DRC. Photo by IITA.
Chikwangues, made from fermented and pounded cassava, for sale at Kolo market, Bas-Congo, DRC. Photo by IITA.

The impact
In-depth interviews with participants revealed four stages by which the program interventions had an impact at the farm household level.

First stage: IITA and INERA undertook the multiplication of breeder and foundation planting materials and the development of new varieties, crop management, integrated pest management, and processing technologies. SECID, FAO, and CADIM implemented rapid multiplication and the large-scale distribution of disease-free planting materials, using a quality control system of primary and secondary nurseries to ensure that large quantities of planting materials were supplied to farmers for establishing their crops.
The Bureau Central de Coordination (BECECO), a government clean seed multiplication and distribution program funded by the World Bank, supported the multiplication and distribution of planting materials and farmers’ training. Community based organizations and farmers’ groups established village-level nurseries for multiplying disease-free planting materials of improved varieties, mostly for farmers within their communities but for some in neighboring areas.

Discussions with researchers, implementation staff, and beneficiaries revealed that the program led to the following outputs:
• The formation of strong partnership and networking among researchers in IITA and INERA, FAO, SECID, CADIM, and PACT-Congo, farmers’ associations, farmers’ groups, and small- and medium-scale enterprises.
• Capacity building resulted in the build-up of knowledge, skills, and competencies at the individual and organizational levels for researchers in INERA, extension agents, farmers, farmers’ groups, processors, and equipment manufacturers. Farmers’ field schools helped farmers to gain experience.
• The development and release of disease-resistant improved varieties. When the program started there were no varieties resistant to EACMV-Ug but in 2–3 years, five varieties had been developed. Eleven additional varieties were released between 2005 and 2008.
• Crop management and crop protection technologies were delivered through breeding for disease and pest resistance, releasing predators for green mite control, and refining extension recommendations.
• Processing technologies and institutional innovations for organizing and linking farmers to markets were delivered after the adoption of improved crop management practices and expansion in cassava production in the targeted areas. Small and medium enterprises engaged in cassava processing emerged as a result of the improved processing technologies to expand their operations and market in micro-chips and other products, such as farinha, gari, and starch.

Second stage: During this stage the outputs were delivered to change agents, including INERA researchers, extension workers, NGOs, farmers’ associations, and private sector companies, resulting in changes in their level of awareness, knowledge, and practices.

The major outcomes perceived at the change agent level were as follows:
• Changes in the practice and behavior of INERA researchers, Government and NGO extension agents, processors, and equipment manufacturers.
• Development of supply systems for clean planting materials of improved varieties, advice on crop and postharvest technology management, locally manufactured processing machines and equipment, micro-enterprises engaged in cassava processing, improved quality of cassava flour, better output marketing and logistics of distributing cassava-derived products to urban consumers.
• Tissue culture and institutional arrangements for the multiplication and distribution of planting materials made possible the distribution of a cumulative total of 417,354,633 one-meter stem cuttings of disease-free improved varieties to 3,530,666 households from 2001 to 2008. However, the total planting materials distributed were sufficient for planting only a lower bound estimate of 166,942 ha, or about 9% of the total national cassava area cropped in 2007/2008 using FAO data or 10% using data from the Service National de Statistique Agricole (SNSA).

Third stage: Here, the research products were delivered to farmers, resulting in increased awareness, knowledge, and adoption of improved practices among farm households in villages exposed to the program’s interventions compared to those living in other villages. Respondents interviewed in this study believed that farmers exposed to the program’s interventions acquired new knowledge that mosaic is a disease. To get good yields, growers needed to obtain disease-free planting materials from INERA research stations or NGO multiplication plots instead of neighboring farmers. Farmers acquired knowledge on using phytosanitation to control the disease.

Fourth stage: Respondents perceived that R4D generated synergies between farmers’ access to and participation in markets, on-farm productivity, and the intensiveness in which parcels of land were cultivated. This, in turn, accelerated the adoption of improved technologies and farm-level impacts. Households in intervention villages that participated in the R4D program were perceived to have achieved better yields, higher profitability, and greater food security than those that did not. Processing added value to the cassava produced in targeted areas and the products were increasingly being sold to urban markets.

Bags of dried cassava chips in Mbuji Mayi, DRC. Photo by IITA.
Bags of dried cassava chips in Mbuji Mayi, DRC. Photo by IITA.

The study
Primary data were collected through a questionnaire interview survey in 2009 to a randomly selected sample of households in areas where the program had been implemented and neighboring nonprogram areas. The survey used stratified random sampling to select contact households. A total of 521 households clustered in 52 villages were interviewed.

The study tested three hypotheses on the impact of the agricultural R4D program on farm-level outcomes of interest:
• The R4D program has causal effects on households’ participation in markets.
• The R4D program generates synergies among improved varieties and crop management technologies and encourages their adoption by farm households.
• The R4D program helps households achieve higher plot-level yields, greater profitability, and improved household food security.

The study established that households in villages where R4D had been introduced had significantly higher levels of sales of cassava compared with households in villages without interventions. R4D was also found to increase the probability of a household adopting most of the technology options. There were high correlations among random utility components which provided evidence for the hypothesis that R4D generates synergies among improved technology adoption decisions.

The study showed that households who lived in intervention villages had significantly higher plot yields, gross margins, and food security than those in nonintervention villages. Marginal effects showed that household participation in a farmers’ organization had the most impact.

The study concluded that the cassava R4D interventions were successful in increasing the outcomes. The finding that the R4D program had positive impacts on intermediate outcomes that can be observed in the short term suggests that the approach has potential for long-term impacts on final outcomes. This implies that policymakers can increase the impact of agricultural research on household food security by promoting agricultural R4D approaches together with the development of farmers’ organizations.

Cassava is the second most important staple in Malawi after maize. The two crops supply over 70% of calories in the diet and sometimes replace and complement each other in production and consumption. They are historically intertwined as both were introduced into Southern Africa from Brazil in the 1500s. However, the colonial and early post-independence agricultural policies favored maize and, as a result, cassava production remained insignificant throughout this period.

Women peeling cassava for processing. Photo by IITA.
Women peeling cassava for processing. Photo by IITA.

The situation, however, changed dramatically between 1994–1995 and 2006–2007 when the area grown to cassava more than doubled and production expanded. This was as a result of a combination of factors including (1) realignment of commodity prices in favor of cassava over maize after the removal of consumer and producer subsidies under structural adjustment; (2) development, dissemination, and adoption of improved technologies; (3) extension to popularize cassava; (4) the collapse of input supply, credit, and maize markets; (4) a decline in soil fertility below the economic yields for maize; and (5) high rainfall variability.

The spread of HIV/AIDS may have also contributed by reducing the rural labor supply and replacing high-labor intensive crops such as maize with labor-saving, low-input crops such as cassava. There was an increased demand for fresh and processed cassava in central Malawi as consumers substituted cassava for more expensive maize and wheat products.

A study applied econometric modeling treatment effects methods to estimate the impact of the cassava R4D projects implemented in Malawi in the 1990s and 2000s on the farm-level yield, per capita area planted to cassava, and food security.

Overview of the program
Formal cassava improvement research started in 1930 in Karonga with the collection and evaluation of local varieties for their yield potential and resistance to cassava mosaic disease. Varieties from Malaysia, Java, Kenya, Tanzania, Trinidad, and Ghana were introduced and evaluated.

Notable highlights include the severe drought and famine in the years 1948–1949 and 1949–1950 that led the Department of Agriculture to distribute cuttings as a drought recovery intervention. However, these years were followed by three consecutive good rainfall seasons that resulted in sufficient maize production, large surpluses of cassava which were not sold due to lack of transport, and reduced interest in the crop except in areas where it was already a staple food.

During the 1950s and 1960s, researchers continued to search for mosaic-resistant varieties from the East African Agriculture and Forestry Research Organization. Agronomic trials were also conducted on intercropping, planting time and method, spacing, harvesting, fertilizer use and land preparation, and on pest and disease control. The findings were formulated into recommendations and made available to extension for dissemination to farmers.

Motorized cassava grating machine commissioned by IITA-CFC in Sierra Leone. Photo by IITA.
Motorized cassava grating machine. Photo by IITA.

Postharvest management research was conducted to develop technologies for processing cassava into flour on a large scale by agribusiness companies. In the 1950s and 1960s, the crop began to emerge as a cash crop in the southeastern districts when private traders exported surpluses of dried cassava to East Africa and the European Common Market. At its peak in 1968, the crop was the fifth highest foreign exchange earner in Malawi after tobacco, tea, groundnut, and maize. But the quality of the dried chips was low because of poor processing methods and could not compete with cassava pellets from Thailand.

From 1978, a parallel cassava research program was set up to evaluate materials from IITA. The breeding scheme used at IITA was introduced to shorten the time taken from identification to variety release, multiplication, and distribution of planting materials to farmers. This resulted in the release of second generation bitter varieties tolerant of cassava mosaic and mealybug in 2000. These were Mkondezi (MK91/478), Silira (TMS601428), and Maunjili (TMS91934). In 2002, the national cassava program released two other cassava mosaic- tolerant bitter varieties, Yizaso (CH92/112) and Sauti (CH92/077).

At the beginning of 1985 there was a serious outbreak of cassava mealybug in the main cassava-growing areas but scientists brought the pest under control in the 1990s by exporting and releasing its natural exotic enemies from IITA.

During 1991–1992 and 1993–1994 there were severe droughts followed by low rains in 1994–1995. In response, the national cassava research and extension programs expanded and accelerated the multiplication and distribution of planting materials for cassava and sweetpotato. This was followed by another food security project from 1998–1999 to 2000–2001 which also incorporated postharvest technologies.

The projects resulted in major changes in the organization and implementation of cassava research. The first change was the smart borrowing of IITA’s procedures for large-scale tissue culture, the rapid multiplication of virus-free planting materials, and distribution systems. The systems consisted of farmers’ groups, researchers, extension agents, traders, processors, religious groups, community based and nongovernmental organizations, and policymakers. Also involved were Bunda College of Agriculture, Natural Resources College, IITA/SARRNET, International Potato Center, FAO, United Nations Children’s Fund, and donors (Office of Foreign Disaster Assistance/United States Agency for International Development, United Nations Development Program, and International Development Research Centre.

The first multiplication and distribution project focused on the supply of ‘‘cleaned” cassava cuttings of improved varieties through a quality control system of primary, secondary, and tertiary nurseries, on-farm technology evaluation and dissemination of improved crop management practices, the development of farmers’ organizations, training, capacity building, and networking.

The second project placed more emphasis on postharvest management and market development. The components were implemented as a package in target areas selected as being food insecure suited to cassava production, and suitably located to minimize the costs of transporting materials from primary multiplication sites at government research stations, agricultural colleges, irrigation schemes, and agricultural training centers and from secondary sites in NGO intervention areas. The planting materials were supplied, based on availability and farmers’ requests, to villages through farmers’ groups and distributed through farmer-to-farmer exchange.

Research findings and conclusions
The study found that the cassava R4D program benefited smallholder farmers and generated significant farm-level impact. Using synthetic control methods to control for observable characteristics it showed that by 1995 annual yields in predominantly cassava-growing and -consuming districts first exposed to the program were about 23% higher than they would have been in the absence of the program.

The study estimated an increase of 14% in per capita area cropped to cassava among households first exposed to the program compared with those that were later exposed. The cassava R4D program led to an average increase of 9.1% for the 1997–1998 cross-section, 9.5% for the 2004–2005 cross-section, and 8% in the before and after changes for households per capita area planted to cassava.

Using the Heckman’s treatment effects model to control for observables and unobservables, the study estimated that participation in the program increased the months a household can meet its minimum caloric requirements from home-produced maize and cassava staples by 66% for a randomly selected household, 18% for those actually selected in the program, and 22% for those at the margin of participation.
Therefore, increasing the impact of cassava R4D at a greater scale requires further investments in an adequate supply of planting materials and market development to transform cassava into both a food and cash crop.

Restoring the IITA Forest

Deni Bown,

Read the Estonian translation by Anna Galovich

IITA lake and forest. Photo by IITA.
IITA lake and forest. Photo by IITA.

In 2010, the International Year of Biodiversity, a new project began at IITA to enhance biodiversity and restore IITA’s Forest. Coincidentally, the United Nations (UN) declared 2011 as the International Year of Forests, and the IITA–Leventis Project is preparing to plant over 30,000 saplings of indigenous tree species this year to restore native forests.

The IITA campus (1000 ha) in Ibadan, Nigeria, now largely within the city limits of Ibadan, was acquired in 1965. The land was mostly bush, interspersed with field crops and 26 villages, whose occupants were relocated. After campus construction and the allocation of fields for crop research, about a third of the site—some 350 ha—was left untouched. In 1987, campus residents created pathways through this regenerating post-abandonment secondary forest, resulting in the Forest Trails we still enjoy today.

After more than 45 years as a reserve, and with continuing loss of forest in southwest Nigeria, this area has become an increasingly important refuge for many plants and animals that were once widespread. Together with an artificial lake at the west margin, the IITA Forest shelters a wealth of animal and plant species and provides a habitat for biodiversity in Nigeria.


The IITA–Leventis Forest Restoration Project aims to:

-Restore the existing forest by removing invasive exotic species, such as Chromolaena odorata, Delonix regia, Gliricidia sepium, Leucaena leucocephala, and Tithonia diversifolia, and replanting the area with indigenous species from seeds, wildlings, and cuttings.

-Protect the IITA Forest against disturbance and theft, in particular, against hunting for bush meat and the collection of medicinal plant parts.

-Catalog the biodiversity of the forested areas, mainly in terms of birds, butterflies, and medicinal plants, and monitor changes.

Junonia cymodoce basking in the sun. Photo by Sz. Safian.
Junonia cymodoce basking in the sun. Photo by Sz. Safian.

-Replant the east bank of the lake with indigenous tree species and carry out research into reforestation techniques.

-Engage in conservation educational activities, especially with young people, to raise awareness of the need to protect forests.

-Form local, regional, and international partnerships in tropical forest conservation, research, and education activities.

The team of rangers and nursery workers from the IITA–Leventis Project is led by Project Manager John Peacock, Project Coordinator and flora/medicinal plant consultant Deni Bown, and Nursery Manager Olukunle Olasupo. In the first year, over 21,000 seedlings of more than 40 indigenous tree species were propagated. Experimental plots were established to record the effects of different ground treatments on the growth of 10 species. Reforesting the east bank was also started by planting trees grown in their first Tree Seed Project by the International School at IITA and by the Institute’s staff.

In addition to the School’s Tree Seed Project, a Garden Club was started to show children how to grow, propagate, harvest, and value edible and medicinal plants. There are regular activities to engage children in observing wildlife and appreciating the forest. Moves are also under way to found a Youth Explorers’ branch of the Nigerian Field Society which will use the resources and expertise at the IITA campus. Educational displays of medicinal plants, butterflies, and photo archives of birds were exhibited at events, and information, both printed and electronic, is provided for the numerous visitors.

Together with the Security Unit at IITA, the team also improved the protection of the Forest.

Ibadan malimbe, an endemic bird species in Nigeria. Source: Leventis Foundation.
Ibadan malimbe, an endemic bird species in Nigeria. Source: Leventis Foundation.

Catalogue of forest resources
The IITA Forest is an internationally acclaimed Important Bird Area (IBA). Since March 2010, over 200 bird species have been identified during surveys by Shiiwua Manu, Phil Hall, John Peacock, Adeniyi Taiye, and Matt Stephens. Similar baseline surveys were carried out for butterflies by Szabolcs Sáfián, Robert Warren, and Oskar Brattström, and brought the total identified in the IITA Forest to 220. Deni Bown has to date recorded 431 plant species at IITA; of these, 382 have medicinal uses.

Flagship species
For many people, the Forest is a place of mystery and beauty but something they may not know much about. By targeting conservation efforts on spectacular species, their interest can be focused. The Project has three flagship species: the Ibadan malimbe, Malimbus ibadanensis, an endangered bird found only in the Ibadan area; the iroko, Milicia excelsa, one of Nigeria’s most important timber trees; and the “PG plant”, Pararistolochia goldieana, a liana (a woody vine) that produces the largest flower in Africa.

Pararistolochia goldieana, a woody vine that produces the largest flower in Africa. Photo by O. Adebayo, IITA.
Pararistolochia goldieana, a woody vine that produces the largest flower in Africa. Photo by O. Adebayo, IITA.

The Iroko is of major economic importance but cannot be grown successfully in plantations. The only place where it is now safe from being felled is within the IITA campus.

Likewise, the Ibadan malimbe and PG plant are totally dependent on the IITA Forest for survival.

Over the past 50 decades, the loss of tropical forests in Nigeria has been catastrophic, giving this fragment in IITA considerable importance. Increasing its extent and biodiversity is part of IITA’s new initiative to conserve biodiversity and create an African Science Park or Innovation Africa™. These are valuable resources for local interests and the wider scientific community.


A hot bath for the suckers!

An effective treatment against nematode and weevil pests of banana and plantain

Plantain plant with three sword suckers, field trial on IITA campus, Ibadan, Nigeria. Photo by A. zumFelde, IITA.
Plantain plant with three sword suckers, field trial on IITA campus, Ibadan, Nigeria. Photo by A. zumFelde, IITA.

Banana and plantain (Musa spp.) are important food crops for millions of people all over the world. The banana is the most popular fruit in the world and number one in international trade. The FAO estimates that over 100 million t of banana and plantain were produced worldwide in 2007. In sub-Saharan Africa (SSA), over 70 million smallholder farmers depend on the two crops for their food and income.

Banana and plantain production is greatly constrained by pests and diseases that lead to annual losses of millions of US dollars. The most important pests are nematodes (several species) and weevils (Cosmopolites sordidus) that are found in the soil and roots.

Nematodes attack the roots, hampering the uptake of nutrients from the soil and drastically reducing yield. In severe cases, they topple the whole plant. Weevils, on the other hand, attack the plant’s underground corm, weakening the plant and causing stem breakage. Average production losses from nematodes are estimated at 30% of the harvests of highland banana in East Africa and can exceed 60% for plantain in West Africa.

These two pests are spread from one farm to another through the planting of infested suckers. Farmers can avoid infesting their farms by ensuring that they plant disease- and pest-free suckers, such as those derived from tissue culture. These are, however, out of reach for the millions of small-scale farmers in sub-Saharan Africa.

Farmers dipping peeled suckers in boiling water. Source: D. Coyne, IITA.
Farmers dipping peeled suckers in boiling water. Source: D. Coyne, IITA.

Research has shown that peeling and treating the suckers in hot water, at 50 °C, can effectively remove both nematodes and weevils and their eggs. This method has worked successfully for commercial farms and organized cooperatives but not for small-scale farmers. This is because a thermometer must be used to ensure precision and the right temperature and this is not readily accessible to the farmers in SSA.

IITA’s scientists Danny Coyne and Stefan Hauser have developed an easier method that is just as effective by simply immersing the peeled or unpeeled suckers in boiling water for 20–30 seconds.

The counting
The duration of 20–30 seconds can be achieved by simply counting from 1 to 30. Farmers can also use small objects, such as pebbles, to mark the time: picking the pebbles one by one and placing them in a small container. The counting takes about 1 second/item but farmers can check the time for more accuracy.

This technique has proven to be friendly to small-scale farmers and is better than the hot water treatment at 50 °C as the time taken to treat a sucker is reduced and the measurement of the temperature and timing is simplified. It effectively disinfects suckers of various sizes without affecting their germination

Plantain field planted with suckers treated in boiling water. Photo by A. zumFelde, IITA.
Plantain field planted with suckers treated in boiling water. Photo by A. zumFelde, IITA.

The method is radical and requires skill and care when it is promoted to farmers who may be sceptical at first. The scientists recommend the use of a demonstration plot to introduce the technology and convince farmers to adopt it. They must keep within 30 seconds as otherwise they risk damaging the suckers, especially those that are small-sized.

Although the technology requires a fuel/energy source and the process has to be followed precisely, it is definitely a much easier method to use than the hot water treatment.

Using boiling water to treat the suckers has the potential to improve banana and plantain productivity by eliminating the two pests.

Investing in aflasafeTM

aflasafeTM is a cost-effective, safe, and natural method for preventing the formation of aflatoxin in maize and other susceptible commodities in the field and also in postharvest storage and processing. It is providing hope for African farmers and opening doors for entrepreneurs looking to invest on a winning formula in the agricultural sector.

Maize farmers receive aflasafeâ„¢ from IITA. Photo by IITA.
Maize farmers receive aflasafeâ„¢ from IITA. Photo by IITA.

Scientific studies suggest that investment in aflasafeTM in Africa is viable, not only for profit but also to improve people’s health. For instance, the study of Wu and Khlangwiset (2010) estimated that the cost-effectiveness ratio (CER; gross domestic product multiplied by disability-adjusted life years saved per unit cost) for aflatoxin biocontrol in Nigerian maize ranged from 5.10 to 24.8. According to the guidelines from the World Health Organization (WHO 2001), any intervention with a CER >1 is considered to be “very cost-effective”.

About aflatoxins
Produced by the fungi Aspergillus spp., aflatoxins are highly toxic fungal substances that suppress the immune system, and cause growth retardation, liver cancer, and even death in humans and domestic animals.

Aflatoxins also affect the rate of recovery from protein malnutrition and Kwashiorkor, and exert severe nutritional interference, including in protein synthesis, the modification of micronutrients, and the uptake of vitamins A and D.

Exposure in animals reduces milk and egg yields. The contamination of milk and meat is passed on to humans after consumption of these products. Aflatoxins affect cereals, oilseeds, spices, tree nuts, milk, meat, and dried fruits. Maize and groundnut are major sources of human exposure because of their higher susceptibility to contamination and frequent consumption.

The toxins are most prevalent within developing countries in tropical regions and the problem is expected to be further exacerbated by climate change.

The high incidence of aflatoxin throughout sub-Saharan Africa aggravates an already food-insecure situation. Agricultural productivity is hampered by contamination, compromising food availability, access, and utilization. Unless aflatoxins in crops and livestock are effectively managed, marketable production and food safety cannot improve. Thus, the economic benefits of increased trade cannot be achieved.
Aflatoxins cost farmers and countries hundreds of millions of dollars annually. These losses have caused crops to be moved out of regions, companies to go bankrupt, and entire agricultural communities to lose stability.

IITA staff producing aflasafeâ„¢ in the lab. Source: R. Bandyophadyay, IITA.
IITA staff producing aflasafeâ„¢ in the lab. Source: R. Bandyophadyay, IITA.

aflasafeâ„¢ to the rescue
An innovative scientific solution in the form of biocontrol has been developed by the US Department of Agriculture’s Agricultural Research Service (USDA-ARS). This breakthrough technology,already widely used in the United States, reduces aflatoxins during both crop development and postharvest storage, and throughout the value chain.

IITA and USDA-ARS have been collaborating since 2003 to adapt the biocontrol for Africa. They achieved significant breakthroughs that resulted in the development of an indigenous aflatoxin technology in Nigeria, now called aflasafeâ„¢. aflasafeâ„¢ contains four native atoxigenic strains of Aspergillus flavus that outcompetes and replaces the toxin-producing strains, thus reducing aflatoxin accumulation.

IITA and partners conducted trials in Nigeria. Native atoxigenic strains reduced contamination by up to 99%. The National Agency for Food and Drugs Administration and Control (NAFDAC) gave IITA provisional registration to begin testing of the inoculum of a mixture of four strains under the trade name aflasafeâ„¢. In 2009 and 2010, maize farmers who applied aflasafeâ„¢ achieved, on average, a reduction of >80% in aflatoxin contamination at harvest and 90% after storage.

Groundnut farmers also achieved more than 90% reduction in Nigeria and Senegal using a version of aflasafeâ„¢ with native atoxigenic strains from Senegal.

In the future
The success recorded so far in the control of aflatoxin comes from aflasafeâ„¢ produced in the lab. Consequently, to meet the demands of farmers in sub-Saharan Africa, large-scale production is needed.

In Nigeria, for instance, nearly 30% of harvested maize has high levels of aflatoxins and is prone to being rejected by the feed industry. In Kenya, last year because of aflatoxin contamination, more than two million bags of maize were declared unfit for human consumption in the Eastern and the Coast provinces. Some countries, such as Senegal, have lost groundnut export market to the European Union due to aflatoxin contamination.

Commercial production of aflasafeâ„¢ would allow easy and widespread availability of a simple solution to the most recalcitrant problem affecting farmers and consumers. The monetized value of lives saved, quality of life gained, and improved trade by reducing aflatoxin far exceeds the cost of aflasafeâ„¢ production.

Wu F and Khlangwiset P. 2010. Health economic impacts and cost-effectiveness of aflatoxin-reduction strategies in Africa: case studies in biocontrol and post-harvest Interventions. Food Additives & Contaminants. Part A, 27: 4, 496—509, First published on: 05 January 2010 (iFirst).

Related website

Aflatoxin management website –