Cadmium and lead contents in compost amended oxisols in the western highlands of Cameroon

This study evaluates the Cadmium (Cd) and Lead (Pb) concentrations of an oxisols in a field where the plots had received one, two, and three year’s application of compost (20 t/ha), together with a control plot. The soil was sampled at depths of 0-10, 10-20, and 20-30 cm for analysis of total Cd and Pb principally, but also other soil physico-chemical properties. Cd and Pb bulk contents were measured by atomic absorption spectrophotometry after HNO3 and HCl digestion. Results indicate that organic carbon contents increased from the control (4.8 ± 0.9 %MS) to the one year cultivated plot (5.5 ± 0.8 %MS), then two years (5.7 ± 0.5 %MS) and lastly three years (5.9 ± 0.4 %MS), showing that compost increased the carbon contents of the soils. The soil acidity in the other hand decrease, the pH value ranged from 5.2 to 6.3. Total Nitrogen (N), Cd and Pb contents increased with the number of years of compost application with the following trends: 0.04 to 0.32 % for N, 0.018 to 0.101 mg/kg for Cd, and 0.73 to 1.74 mg/kg for Pb. Significant correlations were noted between Pb and organic carbon (p < 0.01), Pb and clay (p < 0.05). Compost application increased the concentration of the TMEs in soil.