Effects of Plant Density and Delayed Bean Sowing on Yields, Economic and Nutritional Perfomances of Cassava-Maize-Bean Intercrops: A Case Study in Kirimiro and Mumirwa Agro-ecological zones, Burundi

Cassava-maize-bean intercropping systems testing effects of spacing (plant density) and bean planting date were assessed under two major Burundi agroecological zones (AEZ), Mumirwa and Kirimiro. Evaluated spacing for all three tested crops were as follows: recommended spacing (RS), RS+20 % and RS + 40 %. Bean was planted either at the same time as other two crops or with a 3-week delay. Measured parameters were intercrops’ and total yields, nutrient value (energy, proteins) and economic benefits (gross monetary values, total costs, net returns and value/cost ratio -V/C). Overall measured parameters, beans contributed more in the Kirimiro AEZ, while cassava contributed more in the Mumirwa AEZ. In the Mumirwa AEZ, cassava represented 82 % of the total yields, while bean and maize represented only 11 and 7 %, respectively. In the Kirimiro AEZ, comparative figures were 54 % for cassava, 33 % for bean and 13 % for maize. Cassava represented 64 % of the total energy yields in the Mumirwa AEZ and 20% for maize and 16 % for bean. In the Kirimiro AEZ, similar figures were 34 % for cassava, 46 % for bean and 20 % for maize. Bean contributed 77 % of the total proteins when all three crops were installed at the same time, whereas maize brought in 10 % and cassava 13 % of proteins, respectively. Bean generated 23 % more money in the Kirimiro AEZ while cassava yielded three-times more money in the Mumirwa AEZ. Overall, revenues generated through the cassava + maize + bean intercropping was two times higher in the Mumirwa than in the Kirimiro AEZ. In the Kirimiro AEZ, bean contributed for 60 % of the total monetary values and only 27 % in the Mumirwa AEZ. A similar reflexion applied to cassava indicated that it contributed to the crop yield global monetary value for 67 % in the Mumirwa AEZ and only 30 % in the Kirimiro AEZ. Maize monetary contribution to the global monetary values was 10 % in the Kirimiro AEZ and 6 % in the Mumirwa AEZ. Maize contribution across AEZ was almost insignificant because of its low yields and practiced selling prices. With a V/C ratio of 2.42, the cassava + maize + bean intercropping system was more profitable in the conditions of the Mumirwa AEZ. In the Kirimiro AEZ bean production was 60 % higher when planted at the same time as other crops than when delayed for three-weeks. Similar tendancies were observed for returns (+ 72 %), V/C (+ 34 %), energy (+ 60 %) and proteins (+ 60 %) yields. On the opposite, bean 3-week delay favored maize yield (+ 42 %), energy and proteins yields (+ 42 %). The same trends in agronomic, economic and nutritional values was also observed in the Mumirwa AEZ with lower bean and maize productions but higher cassava yields. In conclusion, all in all, more returns (+ 36 %) were obtained when all three crops were sown/planted at the same time with a V/C ratio = 2.36. In parallel, effect of crop density/spacing indicated that recommended crop spacing increased by 20 % (RS + 20 %) was more economically profitable (V/C=2.39). &nbsp

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

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

Experimental Study and Comparative Effects of Bean (Phaseolus vulgaris L.) crop residues and effective Microorganisms (EM) on the Fertilizer value of Coffee Pulp Compost

In order to evaluate the fertilizer potentials of the coffee pulp as compost, three field experiments were set up with bean (Phaseolus vulgaris L.) and potato (Solanum tuberosum L.). To that end, the fresh coffee pulp was composted with accelerators addition. Evaluated treatments in a Completely Randomized Block Design (CRBD) with 4 replicates were as follows : T1 = Coffee pulp (CP) alone ; T2 = CP + 1 L molasse + 1 L Effective Microorganisms (EM1) + 37 kg of dolomitic lime ; T3 = CP + 16.75 kg of bean residues (BR1) + 16.75 kg of soil (forest soil) ; T4 = CP + 2 L molasse + 2 L EM2 + 74 kg of dolomitic lime ; T5 = CP + 33.5 kg of bean residues (BR2) + 33.5 kg of soil (forest soil) ; T6 = Farm manure + 1.5 T/ha dolomitic lime + 200 kg/ha DAP+ 100 kg/ha KCl + 50 kg/ha Urea and T7 = Control (non amended/fertilised). In both the bean and the first potato (Victoria variety) experiments, recommended organo-mineral fertilization (T6) was not significantly different from either T4 (CP+EM2) or T5 (CP + BR2).  In the second potato (Mabondo) study, T6 (Farm Manure + 60-90-60) produced significantly higher yields than the other treatments (T7, T6, T5, and T4), which did not show any significant differences among them. Across the three field studies, treatments T4 (CP+EM2) and T5 (CP + BR2) are equivalent and substitutable. Nevertheless, being imported, EM is surely problematic with regard to cost, conservation, and manipulation. In that context, we contend that T5 (CP + BR2) is more accessible to farmers and could be widely adopted as a source of organic fertilizer. We then advance that this compost treatment (T5) is the one to be disseminated as a potential coffee pulp-based source of organic fertilizer in coffee-growing Burundi areas. We further propose to test the minerally-complemented T5 (CP+BR2+mineral fertilizers) against the currently recommended Farm Manure+mineral fertilizer applications for bean (18-46-0) and potato (60-90-60) crops. Such an experimental study would evaluate the substitutability of farm manure by CP compost boosted by bean residues addition

Vegetable Yield responses to Coffee pulp Co-composted with Effective Microorganisms (EM) and bean (Phaseolus vulgaris L.) Crop Residues

In a follow-up study to experiments conducted in order to evaluate the fertilizer potentials of coffee, pulp composts enhanced with (micro) biological accelerators on potato (Solanum tuberosum L.) and bean (Phaseolus vulgaris L.) crops, a triple experiment was conducted on two cabbage (Brassica oleracea L.) varieties (Mukasi and Kidodo) and on eggplant (Solanum melongena L.). Tested treatments were: T1=Coffee pulp (CP) alone, T4=CP + 2 L molasse + 2 L EM + 74 kg of dolomitic lime (CP+EM2), T5= CP + 33.5 kg of bean residues (BR) + 33.5 kg of soil (forest soil) (CP+BR2), T6=Recommended organo-mineral fertilizer application for cabbage and T7=Control (non amended/fertilised). The first experiment with the Mukasi cabbage (Brassica oleracea L.) variety showed that CP+EM2 (T4) and CP+BR2 (T5) gave statistically equivalent yields. In the second experiment with the cabbage (Kidodo variety), fresh head yields followed the order: T5 (CP + BR2) ≥ T6 (organo-mineral fertilizer) ≥ T1 (CP alone) ≥ T4 (CP+ EM2) ≥ T7 (Control), indicating the superiority of the coffe pulp co-composted with bean (Phaseolus vulgaris L.) residues. Overall, CP+EM2 treatment (T4) did not perform well, particularly with Kidodo variety. The low performance of CP+EM2 (T4) was confirmed by the eggplant experiment, in which the highest yield was registered with the CP compost alone (T1), followed by CP + BR2 (T5), the control treatment (T7), and lastly by CP + EM2 (T4). In accordance with the previous potato (Solanum tuberosum L.) and bean (Phaseolus vulgaris L.) experiments, we confirm the consistent agronomic superiority of the CP+BR2 treatment (T5) over other tested treatments, including the costly inorganic treatment (T6). This conclusive statement is enhanced by the fact that the CP+BR2 treatment (T5) is more accessible and more reproducible by farmers (because locally available), in comparison with the CP+EM2 treatment (T4). The latter compost treatment is more problematic with regard to cost of acquisition (importation), conservation, manipulation and availability to poor rural Burundi farmers