Properties, Classification and Management Implications of Soils of Illela Sand Dunes, Northwestern Nigeria

Abstract

Soils representative of the stabilised Illela sand dunes in northwestern Nigeria were examined in the field and additional properties of four pedons determined in the laboratory. The soils are deep, dark-brown and sandy throughout their profile. Organic carbon contents are very low, less than 2 g kg -1 , and with the siliceous parent material the consequence is low amounts of available nutrients, particularly Ca, K, Mg and N. However, P is moderate to high due to the occurrence of phosphatic nodules at depth. Available micronutrients, Cu, Zn, Mn and Fe, are generally above the critical limits and are adequate for most crops. The high bulk density and low porosity constituted largely of macroporosity impart low water-holding capacity to the soils. Quartz is the dominant mineral in the sand and silt fractions while kaolinite dominates the clay fraction of the soils. According to the USDA Soil Taxonomy and FAO/UNESCO systems of soil classification, all pedons are classified as Ustic Quart-zipsamments or Ferralic Arenosols, except four pedon 2 which is classified as Arenic Haplustult or Haplic Acrisol. From the general characteristics of the soils, it is recommended that proper organic matter management via the incorporation of crop residues into the soil, the use of organic manure and crop rotation involving legumes, will greatly enhance the productivity of the soils.