Biological, Nutritional and Economic Benefits of Cassava-Maize-Bean Intercropping in Kirimiro and Mumirwa Agro-ecological zones, Burundi

Abstract

Cassava (Manihot esculenta Crantz)-maize (Zea mays L.)-bean (Phaseolus vulgaris L.) intercropping system is common in Burundi. Nevertheless, despite the undeniable predominance of varied intercropping systems in the current Burundi agriculture landscape, national research programs remain focused on monoculture systems. The global objective of this investigation initiated by ADISCO/UPH was to evaluate the comparative advantages of the cassava-maize-bean intercropping system, relative to corresponding monoculture systems under two major Burundi agro-ecological zones, Kirimiro and Mumirwa. The two cropping systems were assessed on their effects on soil fertility, land equivalent ratio (LER), area x time equivalent ratio (ATER), nutrient value (energy, proteins) and economic benefits (total and net returns, value/cost). The study revealed that cassava-maize-bean intercropping resulted in greater biological land-use efficiency (+ 55 %) and an increase in soil fertility parameters (% C, % N, CEC, exchangeable Ca²⁺ and Mg²⁺). Above all, compared to monoculture systems, the gains in energy (kilocalories) associated with the intercropping system varied between + 36% (Kirimiro) and + 59 % (Mumirwa), while those of protein (kg) content ranged from + 28 % to + 51 %, respectively in Kirimiro and Mumirwa. However, the economic efficiency based on the value/cost ratio was low for both cropping systems (V/C=0.6-1.3). From this study, it is transparent that for most farmers, obtaining a well-balanced and regular diet for their family is more meaningful than any other intercropping benefits. In this context, it is more than urgent to find the right crop combinations that would yield better and, at the same time, produce a reasonably well-balanced diet. We then conclude that the development and dissemination of such cropping systems, appropriate to the Burundi rural reality, adapted to climate change, while meeting the nutritional and economic requirements for farmers is, with no doubt the today major challenge for agronomists, extensionists and policymakers alike.