Abstract:

To replore effects of temperature and duration of pyrolysis on physico-chemical properties of biochar,tea branches and twigs were used as raw material in pyrolysis under different temperatures（ 300,450,600 ℃） for 1 and 3 hours,separately,and the biochars were analyzed for properties and element composition. Results show that the biochars were highly porous in structure with a high specific surface area and fairly well maintained organization structure of tea branches and twigs. With rising temperature and extending duration of pyrolysis,the biochar increased in ash content,p H,organic carbon,total phosphorus,total potassium,total calcium,total magnesium and C / N ratio,but decreased in total nitrogen.Meanwhile,ash content was extremely significantly and positively related with pH and was the main contributor to alkalinity of biochar. In addition,the conditions of pyrolysis had significant effects on physico-chemical properties of the tea-twigderived biochar,and the effect of temperature was higher than that of duration. Moreover,the paper also discussed prospects of the application of the tea-twig-derived biochar in tea gardens,and the findings of the study may serve as reference for application of the biochar.

Key words: pyrolysis temperature, pyrolysis duration, tea branch, biochar