Water-stable aggregates of flooded Inceptisols from south-eastern Nigeria in relation to mineralogy and chemical properties

Abstract

Information on the influence of chemical and mineralogical properties on soil aggregate stability of field soils subjected to waterlogging at some time of the year is essential for better management of these soils. We studied water-stable aggregates (WSA) of various sizes for clay flocculation index, soil organic carbon, total elements, and mineralogy of the soil, and related these properties to aggregate stability. Five soil profiles sited on the floodplain of the River Niger were studied. The topsoils were dominated in all profiles except near the river by WSA > 2.00 mm. Also the mean-weight diameter (MWD) of the topsoil followed the trend in WSA > 2.00 mm. Thixotropic age hardening appeared to be responsible for the rather high values of WSA > 2.00 and MWD in the topsoil. Soil organic carbon content associated significantly better with macroaggregates than microaggregates. The aggregating effects of the polyvalent cations manifested more on the microaggregates. The stabilising role of various forms of Fe, Al, and Mn oxides is believed to be as result of their large surface area, abundance, and the favourable environment for their formation. These polyvalent metals may have formed bridges between clay and organic matter in the formation of aggregates.