Temperature effect on biochar produced from tea (Camellia sinensis L.) pruning litters: A comprehensive treatise on physico-chemical and statistical approaches

Abstract

The present study aimed to optimize the production of biochar from tea (Camellia sinensis L.) pruning litter. Characterization of biochar prepared from four tea pruning litters (mixed, Tocklai Vegetative 1, 22 and 25) at five pyrolysis temperatures (250, 300, 350, 400, 450, and 500 °C for 3 h) were documented. The results demonstrated that yield, total nitrogen, H:C, and O:C decreased steadily with increasing pyrolysis temperature. However, water holding capacity, ash content, fixed carbon, C:N, NH4+-N, NO3–-N, trace elements, total P and K, and germination index increased consistently with increasing pyrolysis temperature. All the prepared biochars are suitable for agriculture application as H:C and O:C ratios of prepared biochars are <0.6 and <0.4, respectively. Low pyrolysis temperature (<300 °C) was optimal to get more stable biochar with respect to essential nutrients. Biochar derived from Tocklai Vegetative 1 at 300 °C has more potential for agronomic applications. Principal component analysis showed >96% variability.