A diverse range of physicochemically-distinct biochars made from a combination of different feedstock tissues and pyrolysis temperatures from a biodiesel plant Jatropha curcas: A comparative study

摘要

Jatropha curcas (Jatropha) is drought-resistant and produces seed oil that is suitable for biodiesel fuel production. During cultivation, Jatropha produces a large amount of non-oil biomass from fallen leaves and pruned branches; however, their utilization has been largely unexplored. In the present study, we evaluated the potential of Jatropha non-oil biomass as a feedstock for biochar that could be utilized as a soil modifier and fertilizer for sustainable farming. A total of 12 different Jatropha biochars were produced using a combination of three tissue types (leaf, trunk, and branch) and four pyrolysis temperatures (300, 400, 500, and 600 degrees C), and their physicochemical properties were comparatively analyzed. For each tissue type biochar, a general trend of increasing pH and electrical conductivity, and decreasing yield and cation exchange capacity was observed as the pyrolysis temperature increased. The leaf biochar had significantly lower carbon and higher nitrogen, phosphate, potassium, and magnesium contents than that of the other tissue biochars, whereas the trunk biochar had the highest calcium content among all the biochars. Except for the leaf biochar pyrolyzed at 300 degrees C, all biochars significantly improved the water holding capacity of silica sand applied at a 1%(w/w) concentration. Pearson's correlation and principal component analyses highlighted a wide range of biochars with divergent physicochemical properties, which were characterized by nitrogen, phosphate, and magnesium richness in the leaf biochar; and calcium richness in the trunk biochar. Therefore, a specific combination of pyrolysis temperature and tissue type from Jatropha non-oil biomass could serve as a feedstock for tailor-made biochar products for various agronomic needs such as soil modifiers and fertilizers.