Determination of Total Content of Some Microelements in Soil Using Two Digestion Methods

Aqua regia and tri-acid digestion methods were applied for the analysis of some soil microelements. The total number of 243 soil samples was digested using the two different methods and total Iron, Manganese, Zinc, and Copper were measured in extracted solutions using atomic absorption spectrophotometer (AAS). The obtained results showed a strong correlation between two digestion methods of microelements, r=0.95, 0.81, 0.85 and 0.84 for Iron, Manganese, Zinc, and Copper, respectively. The two methods of digestion were able to extract the total content of microelements with similar efficiency. The aqua regia method was found to be less chemical consuming, less harmful to the environment, time and cost-efficient than the tri-acid digestion method. Thus, the aqua regia method of digestion is strongly recommended for analysis of the total content of microelements in soils.