Cadmium Desorption Kinetics in the presence of the soft Almond Husk Compost and Biochar in a Calcareous Soil

Cadmium (Cd) is one of the most common and dangerous environmental contaminants. The effect of soft almond husk compost and its biochar was studied in the kinetic of cadmium desorption on a calcareous soil in the field of Shahid Bahonar Agricultural College, Kerman. For this purpose, compost and biochar of soft almond husk were used in three Levels (0, 2 and 4 % w/w) and were added to calcareous soil contaminated with three levels of cadmium (0, 40 and 80 mg kg-1). Sampling from treated soils was carried out 45 and 90 days after the contamination of soils with cadmium. Samples from treated soils were extracted by EDTA in 5 to 2880 minutes in different periods of time and the concentrations of cadmium were measured. The results showed that the application of compost and soft almond husk biochar reduced the desorption of cadmium compared to the control. The lowest amount of cadmium desorption occurred at level 4% w/w biochar and compost, while biochar had the highest reduction amount in the desorption of cadmium compared to the soft almond husk compost. Based on the experimental results, the cadmium desorption was highest in all treatments at initial times and decreased over the time. In other words, 50% of cadmium desorption occurred in the first 2 hours. In 90-day sampling compared to 45-day one, cadmium desorption from soil showed the highest decrease. Based on the determination of coefficient and standard error, the power function equation is considered as the best predictor of the cadmium release kinetics trend in the studied soil.