Potentially mineralizable nitrogen in West African lowland rice soils

• Published in: Geoderma Vol. 76; no. 1; pp. 145 - 154
• Main Authors: Narteh, L.T., Sahrawat, K.L.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.03.1997
• Subjects: AFRICA OCCIDENTAL; AFRIQUE OCCIDENTALE; AZOTE; MATERIA ORGANICA; MATIERE ORGANIQUE; MINERALISATION; MINERALIZACION; MINERALIZATION; N mineralization capacity; NITROGEN; NITROGENO; ORGANIC MATTER; ORYZA SATIVA; principal components analysis; soil characteristics; TERRE HUMIDE; TIERRAS HUMEDAS; waterlogged incubation; WEST AFRICA; wetland soils; WETLANDS; waterlogged incubation; wetland soils; N mineralization capacity; principal components analysis; soil characteristics
• ISSN: 0016-7061; 1872-6259
• DOI: 10.1016/S0016-7061(96)00097-3

Nitrogen (N) deficiency is a major constraint to rice production in West Africa. Little information is available on the N supplying capacity of soils used for wetland rice production in West Africa. Potentially mineralizable N, as a measure of N supplying capacity, was determined employing an anaerobic incubation test in 15 diverse soils from 5 major rice producing countries in the sub region. Mineralized N contents of the soils varied widely (21 to 166 mg kg −1 of soil) and the ammonium N released constituted 2 to 7% of the total N. Mineralized N was significantly correlated with pH, organic C, total N, clay and CEC but not with extractable iron and C/N ratio of the soils. Multiple regression analysis of mineralized N with soil characteristics showed that inclusion of C/N ratio and extractable iron improved the prediction of mineralized N. The results underscore the importance of organic matter (organic C and total N) in controlling potentially mineralizable N in wetland rice soils. The main soil factors affecting N mineralization, identified by principal components analysis, accounted for over 97% variation in potentially mineralizable N in the soils.