Soil aggregate stability and erodibility in different gully sites in parts of Kaduna State, Nigeria

Abstract

This paper assesses soil aggregate stability and erodibility in different gully sites in parts of Zaria, Kaduna State, Nigeria with the aim to provide quantitative information on the variation of some soil properties and their interaction with eroding agents and how this affects soil erosion on the sites. The gullies selected are found at the headwaters of river Saye, Yashi, Guga and Kubanni basins with leached ferruginous tropical soils developed from the basement complex and quaternary deposits drained by River Galma whose pattern is basically dentritic. Soil samples collected from the headscarps, sidewalls and floor of each gully length at 5 – 10 cm depth were analysed using standard laboratory methods. Particle size distribution data was used to compute clay ratio index. The result shows that based on aggregate stability the most susceptible to water erosion is the Yashi gully site. Soil particle size distribution in all the gully sites show soil textural classes of silt loam, sandy loam, sandy loam and sandy clay loam at Guga, Saye, Kubanni and Yashi gully sites respectively. Based on clay ratio index (3.58) Yashi show more resistant to erosion followed by Saye with a mean clay ratio index of 4.02, then Kubanni with a mean clay ratio of 10.89 and lastly Guga with a mean clay ratio of 13.06. Results show there is a significant variation of clay, silt, sand, clay ratio and aggregate stability with gully sites at 0.05 levels of significance. A linear multiple regression analysis was used to check the contribution or influence of each independent variable on the dependent variable. Clay ratio index was also derived. The Research concludes that though all sites exhibit gully erosion the reaction of soil properties to environmental conditions varies. Slightly different efforts will be required to turn around the gullies.

Key words: Aggregate, Erodibility, Gully, Soil, Stability, Texture