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

Abstract

In order to evaluate the fertilizer potentials of coffee pulp as compost, three field experiments were set up with bean (Phaseolus vulgaris L.) and potato (Solanum tuberosum L.). For that end, fresh coffee pulp was composted with accelators 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 organomineral fertilization (T6) was not significantly differerent from either T4 (CP+EM2) or T5 (CP + BR2). In the second potato (Mabondo) study, T6 (Farm Manure + 60-90-60) producted significantly higher yields than the other treatments (T7, T6, T5, and T4), which did not show any significant differences among them. Accross the three field studies, treatments T4 (CP+EM2) and T5 (CP + BR2) are equivalent and substituable. 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 experim