This study was conducted to investigate the agronomic performance of the organo-mineral fertilizer FOMI-IMBURA N-P2O5-K2O-CaO-MgO (9-22-4-13-2) compared to the currently recommended DAP dose for bean cultivation.
Field trials were set up at ISABU research stations using a split-plot design with three replications, on dwarf (CODMLB003 and RWR2245) and climbing (MAC44 and Muhoro) varieties with five treatments: 10 T/ha of manure (control); 100 kg/ha DAP + 10 T of manure; 100 kg/ha FOMI-IMBURA + 10 T of manure; 200 kg/ha FOMI-IMBURA +10 T of manure and 100 kg/ha DAP + 50 kg/ha KCl+10 T of manure.
Concurrently, field trials were conducted in all communes of Burundi with 2,320 farmers (20 farmers per commune) using 180 varieties, including 111 climbing bean varieties and 69 dwarf bean varieties. The treatments compared were 150 kg/ha DAP and 150 kg/ha FOMI-IMBURA.
At the experimental stations, the results showed that average bean yields were similar for the following treatments: 100 kg/ha DAP + 10 T of manure; 100 kg/ha FOMI-IMBURA + 10 T of manure; 200 kg/ha FOMI-IMBURA + 10 T of manure; and 100 kg/ha DAP + 50 kg/ha KCl + 10 T of manure. The double dose of FOMI-IMBURA (200 kg/ha) and the treatment of 100 kg/ha DAP + 50 kg/ha KCl resulted in slightly lower yields than those obtained with 100 kg/ha of FOMI-IMBURA.
In real-world conditions, the results showed that for climbing beans, the average yield obtained with 150 kg/ha of FOMI-IMBURA in 14 out of 17 provinces was, in absolute terms, higher than that obtained with 150 kg/ha of DAP, even though the two treatments were statistically in the same group of homogeneous means.
However, in the provinces of Bujumbura, Muyinga, Rumonge, Rutana, and Ruyigi, the FOMI-IMBURA formulation resulted in significantly higher average yields (p<0.05) than those obtained with DAP at equivalent doses. The same trend was observed for dwarf beans in 16 out of 17 provinces, with average yields obtained with FOMI-IMBURA significantly higher (p<0.05) than those recorded with DAP. The exception was Mwaro province, where yields obtained with DAP fertilizer were higher than those recorded with FOMI-IMBURA fertilizer.
Furthermore, when data are compiled for all provinces and by bean type (dwarf and climbing), the average yield obtained with FOMI-IMBURA is significantly different from, or even much higher than, that obtained with DAP at 150 kg/ha.
In conclusion, FOMI-IMBURA provides similar or higher yields compared to DAP. Consequently, FOMI-IMBURA fertilizer can advantageously replace DAP for fertilizing climbing and dwarf beans in Burundi.