Artmisia ordosica was used as the experimental material for making biochar in this study. The effects of carbonization temperature on the pH and total K, Ca, and Mg of Artmisia ordosica biochar were investigated. The results showed that the concentrations of K, Ca, and Mg in the biochar increased with the increase of carbonization temperature. Compared with those at 300℃, the K, Ca, and Mg concentrations increased by 52.47%, 25.76%, and 86.32% at 900℃, respectively. The increase of element concentration is due to gradual removal of the volatile and decomposable components in Artmisia ordosica under different carbonization temperature. The heating process of carbonization enriches K, Ca, Mg, and other elements (relative enrichment coefficient RE>1). Low temperature contributes to the enrichment of K and Ca, while medium temperature is favorable for Mg. The RE of the three elements reached their maximum values at 300, 300 and 500℃, being 1.17, 1.15, and 1.22, respectively. The pH increased with the increase of carbonization temperature. The alkalinity of the biochar was correlated to the enrichment of the three elements, and the number and types of oxygen-containing functional groups at the biochar surface, and it had good correlation with the total alkaline functional groups at the surface of the biochar (with correlation coefficient of 0.8665).

Artemisia ordosica  /  biochar  /  carbonization temperature