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Effect of slope and depth on soil chemical properties of a typical alfisol

Nnenne Bassey Anwanane, Kehinde Olayemi Affinnih, John Olajide Olaniyan Olaniyan (original scientific paper)


Management options proffered with respect to the chemical properties along a toposequence are a key to sustainable crop and soil productivity since nutrient status and soil properties are related to topography of the land area. A study was conducted to evaluate the effect of slope and depth on selected soil chemical properties at the University of Ilorin Teaching and Research Farm in 2013. Three points: upper, middle and bottom slope, along a toposequence with an average distance of 200 m apart were delineated and sampled for soil analysis at depths of 0–30 cm, 30–60 cm and 60–90 cm using core sampler and auger. Soil chemical properties which included pH in water, pH in KCl, electrical conductivity, organic matter, total nitrogen, available phosphorus, exchangeable bases (Ca, Mg, K, Na), exchangeable acidity, effective cation exchange capacity, base saturation, exchangeable sodium percentage and sodium adsorption ratio were determined in the laboratory/ computed afterwards. Data from the analysis were subjected to ANOVA using 2×3 factorial combinations of factors slope and depth – in randomized complete block design (RCBD) with five replicates. Results on the effects of slope and soil depth on soil chemical properties showed that soil depth affected all the measured soil chemical properties except exchangeable sodium. The pH (both in water and KCl), electrical conductivity, available phosphorus and exchangeable potassium were not affected by slope. Also, pH, exchangeable magnesium and sodium were not affected by the interaction between the effect of slope and soil depth.

Correspondent author:
Kehinde Olayemi AffinnihDepartment of Agronomy, Faculty of Agriculture, University of Ilorin, PMB 1515, Ilorin, Kwara State Nigeria,