Banana (Musa) is a key component of farming systems in the Great Lakes Region with annual per capita consumption in Rwanda, Burundi, and DR Congo estimated at 250 to 400 kg/year (Kilimo Trust 2012). Apart from being a key staple, banana is also a principal source of income for farmers. It has also become an important component of mixed production systems, intercropped with perennial and annual crops such as coffee and beans.
However, banana production in this region is constrained by several factors such as limited access to and use of healthy and improved planting materials and inefficient agronomic practices resulting in low yields (IITA/FAO 2014; Schut et al. 2016). The introduction of improved and elite varieties in smallholder production systems can overcome these challenges, but they are seldom deployed in appropriate combinations with other crops.
In 2006, IITA played a crucial role in initiating the Consortium for Improving Agriculture-based Livelihoods in Central Africa (CIALCA – www.cialca.org). CIALCA conducted research that could support smallholder production systems in becoming both highly productive and profitable using intercropping as an option to maintain soil fertility and maximize crop yields. Intercropping is also promoted to mitigate crop failure risk, reduce pest and disease incidence, and to control weeds and soil erosion.
Since its inception, CIALCA has been conducting research for development with a broad focus on increasing food, income, and nutrition security in the Great Lakes Region. CIALCA meets these challenges by building partnerships with research, government, and development partners to access and deliver appropriate agricultural innovations for use by smallholder farmers. One of the innovations that CIALCA is promoting with partners is the intercropping of legumes and vegetables in banana production systems.
Bananas and beans, a likely couple
The intercropping of bananas and beans (Phaseolus vulgaris L.) is a common production practice in the Great Lakes Region. In onfarm experiments by CIALCA, a variety of bush bean (RWR2245) was evaluated in sole crop and in association with different banana varieties (Injagi, FHIA 17, and FHIA 25) to determine bean and banana yields in monoculture and as intercrop (Figs. 1 and 2). Trials were established in a randomized complete block design with 3 replicates of 9 banana plants per replication spaced at 3 m × 3 m, and bean intercropped at a spacing of 40 cm × 40 cm.
Results showed that apart from banana cultivar Injagi, yield of improved varieties FHIA 17 and FHIA 25 in the intercrop system was significantly different and could be attributed to competition for soil moisture and nutrients as the improved varieties appeared to be more competitive in the intercrop system. On the other hand, the difference observed in bean yield when intercropped with banana could be attributed to shading. Variety effect showed that FHIA 17 and FHIA 25 gave significantly higher fresh bunch yields compared to the local cultivar Injagi, irrespective of the location, with FHIA 17 performing better.
Banana intercropping: The case of Rwanda
In Rwanda, 200 farmers were observed and interviewed in 2015−2016 to assess the suitability and profitability of intercropping banana (Mukarugwiza 2016). Correspondence analysis showed that there is no structured variation in monoculture banana production in terms of plant density (3 m × 3 m or 1100 plants/ha) but two other production systems were identified: (1) association with coffee and fruit trees; and (2) association with legumes and vegetables during field establishment.
Results of benefit-cost ratio (BCR) analysis indicate that banana intercropped with vegetables is more profitable with a BCR of 5.4, followed by coffee at 4.8, and common beans at 4.4. These imply that the production systems are suitable and profitable, returning $5.4, $4.8, and $4.4 for every $1 invested in vegetable, coffee, and common beans, respectively.
Inclusion of taro, eggplant, and pumpkin with varying degrees of shade tolerance after nitrogen-fixing legumes when banana has already developed a dense canopy is beneficial to smallholder farmers for year-round use of available space, light, and soil moisture. To increase farmer access to healthy and improved banana varieties, over 400 farmers were trained on banana macropropagation techniques.
Banana intercropping pays more, really!
Edward Habinshuti of Uwingando village in Kamonyi District swears by the profitability of banana intercropping. His multicrop farm produces over 1500 seedlings of banana and he harvests about 200 bunches (worth $1200) monthly. His wife intercrops groundnut during the early stage of banana development, harvesting 2−3 cycles of groundnut (worth $1500) before the bananas develop dense canopy. Edward says that he used to harvest about three bags of maize from his farm, but the returns from the banana and groundnut are worth 5 times more. He adds that with the bananas, nothing goes to waste as he uses the peels, leaves, and pseudostems as feed for his goats. In return, he uses the goat manure to fertilize his banana plants—a good deal indeed!