EFFECT OF DIFFERENT LAND USE ON SOME SELECTED PHYSICOCHEMICAL PROPERTIES AND MICRO-AGGREGATE STABILITY INDICES IN TWO AGRO-ECOLOGICAL ZONES IN EKITI STATE, SOUTHWESTERN NIGERIA.

 ABSTRACT

A study was conducted to investigate changes that may occur in the soil due to conversion of forest land to plantation, fallow and arable lands. Four locations in two-agro-ecological zones at Ikole Local Government Area, Ekiti State, were used for this study. They are; Itapaji (L 1), Asin (L2); in rainforest agro-ecological zone and Odo-Ogo (L3), Odo-Ayedun (L4) in derived savannah. Soil parameters evaluated include particle size distribution, bulk density, saturated moisture content, total porosity, total nitrogen, available phosphorus, exchangeable potassium, organic matter, pH, micro-aggregate indices measured by CDI (clay dispersion index), CFI (clay flocculation index), WDC (water dispersible clay), DR (dispersion ratio), ASC (aggregated silt+ clay). The experiment was arranged as a 4 x4x 2 factorial, replicated three times in a randomized complete block design. The result show that forest conversion to other land use types caused a significant (P:::;0.05)decline in clay content, organic matter, porosity, saturated moisture content, total nitrogen and clay flocculation index (CFI). However, forest conversion did not cause a significant decline in saturated moisture content, total nitrogen, clay flocculation index or increase in clay dispersion index compared to plantation land use. It caused significant (P:S0.05) increase in bulk density, clay dispersion index (CDI), and sand fraction, while the effect on the silt content, available phosphorus, exchangeable potassium, aggregated silt + clay, dispersion ratio and water dispersible clay was not significant. The interactions of agro-ecological zone with land use, landuse, agro-ecological zone and location were not significant on soil properties for majority of the locations across the two agro-ecological zone. This might be attributed to similar texture (sandy loam) indicated in about 75% of the locations across the four land use types and agro-ecological zones under study.

Keywords: Landuse, soil physical properties, soil chemical properties, agro-ecological zone, micro-aggregate stability indices.