Browsing by Author "Sirikare, N.S."

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    Chemical properties of travertine from different sources in Rwanda with regards to their calcium oxide and magnesium oxide contents
    (Sokoine University of Agriculture, Tanzania., 2012) Sirikare, N.S.; Naramabuye, F.X.; Marwa, E; Semu, E.
    This study was conducted in the districts of Rusizi, Korongi and Musanze districts, Rwanda in areas where travertine is found. The objective of the study was to characterize the chemical compositions of travertine for use in amending soil acidity for crop production. Thirty two samples of travertine from different deposits at Mashyuza (Rusizi), Gishita (Karongi) and Mpenge and Rwaza (Musanze) were analysed to establish their CaO and MgO contents. Percentages by weight of CaO and MgO in samples were determined using X-ray fluorescence. Results revealed that travertine from Mashyuza and Rwaza has the highest CaO wt% content followed by Gishyita. Mpenge deposits had the lowest content CaO% . There was no significant difference among sites for MgO contin travertine. The tratio of CaO:MgO in Mpenge, Mashyuza and Gishita was within a range required to prevent deficiency of Ca and Mg in acid soils where maize and beans are grown.
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    Proton consumption capacity, ash alkalinity and chemical characterization of travertine from different sources in Rwanda
    (Department of Soil Science Sokoine, University of Agriculture, Tanzania., 2014-08-06) Sirikare, N.S.; Naramabuye, F.X; Marwa, E.; Semu, Ernest
    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 CI, 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 zource of micronutrients for agricultural production.