PROPERTIES, CLASSIFICATION AND MANAGEMENT IMPLICATIONS OF SOILS OF ILLELA SAND DUNES, NORTHWESTERN NIGERIA

Soils representative of the stabilised Illela sand dunes in northweste rn Nigeria were examined in the field and additional properties of fou r pedons determined in the laboratory. The soils are deep, dark-brown and sandy throughout their profile. Organic carbon contents are very l ow, less than 2 g kg(-1), and with the siliceous parent material the c onsequence is low amounts of available nutrients, particularly Ca, K, Mg and N. However, P is moderate to high due to the occurrence of phos phatic nodules at depth. Available micronutrients, Cu, Zn, Mn and Fe, are generally above the critical limits and are adequate for most crop s. The high bulk density and low porosity constituted largely of macro porosity impart low water-holding capacity to the soils. Quartz is the dominant mineral in the sand and silt fractions while kaolinite domin ates the clay fraction of the soils. According to the USDA Soil Taxono my and FAO/UNESCO systems of soil classification, all pedons are class ified as Ustic Quartzipsamments or Ferralic Arenosols, except four ped on 2 which is classified as Arenic Haplustult or Haplic Acrisol. From the general characteristics of the soils, it is recommended that prope r organic matter management via the incorporation of crop residues int o the soil, the use of organic manure and crop rotation involving legu mes, will greatly enhance the productivity of the soils.