Coffee and banana yields in the East African highlands are often only 10 to 30% of those achieved in commercial farms in Latin America and Asia. This is the result of a mixture of biotic stresses on the crops such as pests, diseases, and weeds, and abiotic constraints such as poor soil quality and drought.
Poor crop management practices that do not sufficiently address these constraints prevent farmers from reaping maximum benefits from their efforts.
However, the importance of these yield-limiting factors differs from region to region. The natural resources management (NRM) approach therefore starts with identifying the gap between the actual, attainable, and potential yields for each location.
Diagnostic surveys and analytical tools such as the boundary line analysis are used to rank and quantify the causes of low yields. This then guides the development of tailor-made measures and actions for farmers.
Smart use of mineral fertilizer and organic matter
Poor soils are one major cause of low yields in the East African highlands. Much of Africaâ€™s soils are old and poor, situated on very old continental plates. Only a few places have soils that still have substantial nutrient stocks, such as those derived from young volcanic material and metamorphic rocks.
Years and years of soil erosion and poor farming methods that mine minerals have worsened the situation.
IITA is working with farmers to combine organic manure and mineral fertilizer to replenish soil nutrients to meet the needs of banana and coffee.
Piet van Asten, IITA systems agronomist based in Uganda, says the approach stresses the judicious use of mineral fertilizer that is moderate in quantity, applied at the right time and in the right way, and combined with locally available organic matter.
â€œThe combination of fertilizers and organic matter provides much-needed additional nutrients that are efficiently used up by the crops. The organic matter helps to retain mineral fertilizers applied in the topsoil and reduces losses from leaching,â€ he says. â€œIt also improves the soil physical properties which help to retain soil humidity and control the temperature. Plants thrive in such humid and temperate environments as the roots are better able to take up nutrients.â€
Sources of local organic matter are mulch, urine, manure, and compost.
Research has shown that adding mineral fertilizers and mulch to both coffee and banana nearly doubles their yields. However, the fertilizer type and dose have to supply the nutrients that are lacking.
Through mapping soil and plant nutrient status, IITA identified the missing nutrients in each region. Subsequently, it developed region-specific recommendations for using fertilizer and organic mulch in parts of Uganda.
Training materials were also developed to teach farmers how to identify nutrient deficiencies in their own farms by observing plant leaves. This should ultimately help them to localize their fertilizer needs down to the farm level.
Halting and preventing soil erosion by placing contour bunds stabilized by forage/mulch grasses and leguminous plants are also important to conserve and improve soil quality.
Smart intercropping systems
IITA has been working on promoting the intercropping of banana/plantain and coffee as research has clearly shown that intercropping works better than monocropping either crop.
Coffee, a shade-loving plant, performs well when grown under banana/plantain. Research findings showed that creating space for the banana/plantain does not reduce the yield of coffee but instead, the farmer gets bonus income from the banana.
Such intercropping systems, says van Asten, spread the socioeconomic risks of farmers as they become less vulnerable to the price fluctuations of a single crop.
â€œThe two intercrops provide farmers with permanent piecemeal harvests from banana and annual or biannual cash booms from coffee,â€ he said.
Intercropping has other benefits. It leads to sharing of inputs, such as fertilizers purchased through the cash crop system, such as coffee farmersâ€™ cooperatives. It also improves fertilizer-use efficiency, as fertilizer applied to the cash crop also benefits the food crop.
Intercropping improves the biophysical efficiency of the systems by providing better and more permanent canopy and soil cover that reduce erosion. It improves soil organic carbon stocks (carbon sequestration) through the biomass produced.
Another benefit, says van Asten, is that intercropping can sometimes increase the quality of some crops. For instance, under suboptimal growing conditions, shade-grown coffee is often of better quality and thus could fetch more money on the market.
Linking to input and output markets
In a study of the factors that limit farmersâ€™ usage of mineral fertilizers for their banana plants, Uganda farmers cited lack of access as one constraint. Moreover, they said it was not available in smaller packaging and more affordable sizes. IITA is working to encourage farmer cooperatives that are organized around postharvest handling, sorting, and bulking to organize the supply of inputs such as fertilizer for their members.
According to van Asten, cooperatives have better access to input/output markets and improved powers of negotiation. They have improved access to market information, bulking and storage facilities, savings and credit schemes through collaboration, and agreements with input/output dealers. They can also facilitate the exploration of niche markets through the certification of products in terms of quality, production, and techniques.
Smart extension services
To meet the information needs of farmers, IITA and partners are exploring options to make location-specific information accessible. This includes the use of extension publications, videos, and mobile phone services.
Together with the Grameen Foundation, IITA is exploring how information can be tailored to the location of the farmer through a (decision-tree) series of questions. The more information a farmer can provide, the more precise the recommendations will be.
The NRM work on coffee and banana shows that there are practical, readily available measures that farmers can use to increase yield and contribute towards the fight against poverty and hunger. However, they have to be region- and crop-specific for maximum impact.
â€œFor all these measures to be successful, they must start with using clean and resistant planting materials. Investing in fertilizers for use on diseased plants is a futile exercise,â€ concludes van Asten.