Effet de la combinaison DAP, chaux dolomitique et fientes de poule sur la réduction de la toxicité aluminique d’un sol acide d’altitude du Burundi

A 90-day greenhouse study evaluated the combined effect of [(NH4)2HPO4], chicken (Gallus gallus domesticus) manure and dolomitic lime (CaCO3.MgCO3) on exchangeable Al3+reduction,  growth and biomass yield of common bean (Phaseolus vulgaris L.) grown on an acidic high altitude soil collected at Gisozi, Mwaro province. The investigation combined 3 application rates of chicken manure (0, 2.5 and 5 T/ha) and lime (0, 0.5 and 1 T/ha)with a unique application rate of 100 kg of DAP per hectare. Obtained results on common bean crop showed highest growth performances by the combination of 100 kg DAP + 5 T/ha of chicken manure + 1 T/ha of lime. Nevertheless, the latter treatment was not significantly different with some lower application rates, including2.5 T/ha of chicken manure combined with 0.5 T/ha of lime. The latter application rate completely neutralized the exchangeable Al in the used soil, as did higher application rates of chicken manure and lime. A global analysis of bean growth performance coupled with the results of exchangeable acidity neutralization show that the combination of 2.5 T/ha of chicken manure and 0.5 T/ha of lime could be considered the most economically efficient. As a matter of fact, chicken manure constitutes an organic amendment with the particularity of bringing in quite large quantities of Ca2+and Mg2+.Hence, chicken manure has a dual liming potential, via Al3+ detoxification through chelation and chemical displacement and neutralization of Al3+by Ca2+and Mg2+.