Abstract

Sirikare N.S., Naramabuye F.X. Marwa E. and Semu E

Soil acidification is among the major factors limiting the sustainability of agricultural production systems throughout the world and more specifically in Rwanda. Travertine samples collected from different deposits in Rwanda were examined for their chemical compositions. Calcium oxide (CaO) content, ash alkalinity and protons consumption capacity were determined as potential indicators to predict the efficiency of travertine. The results found revealed that the studied travertine deposits (Rwaza, Mashyuza, Gishyita and Mpenge) in Rwanda had 35 to 71.1 wt% CaO. Magnesium Oxide (MgO) ranged between 3.1 and 12.7 wt%. Travertine had micronutrients Cl, Zn, Cu, Mo and Co that can offset deficiency encountered in highly weathered Rwandan acidic soils. In addition, these travertine deposits had higher proton consumption capacity and ash alkalinity as compared to other liming materials. The study revealed positive linear correlations among all the investigated indicators, which could serve as a model for predicting proton consumption capacity and ash alkalinity of any liming material when its pH and CaO content are known. It was recommended that travertine from Rwanda could be used for soil acidity amelioration and a potential source of micronutrients for agricultural production.