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