| Abstract |
The in-field burning of sugarcane leaf residues presents a major environmental and health burden in Thailand. In
this study, sugarcane leaves were converted into a biochar-based slow release phosphorus (P) fertilizer via pyrolysis at 600 °C, and the influence of pre- and post-pyrolysis treatment on the P loading and release was investigated. The sugarcane leaves were pre-treated with an alkaline (diammonium phosphate, DAP) or an acidic P
source (phosphoric acid, PA), with or without addition of MgO. Additionally, the biochar was post-treated with
DAP to increase the P loading. Extraction of P in DI water and 2% formic acid were used as indicators for potential slow release. The microporous biochars had a specific surface area of 69–333 m2 g
−1 and pre-treatment resulted in a P content of 34–82 g kg−1
. When MgO was included in the pre-treatment, XRD analysis confirmed formation of crystalline Mg2P2O7, irrespective of the P source. This Mg2P2O7 was responsible for slow P release in DI
water over 240 h via a dissolution-controlled process. Post-treatment with DAP increased the P loading to
156 g kg−1
in the form of water-soluble monoammonium phosphate (MAP), which did not contribute to slow release. The tunable P release via combinations of pre- and post-pyrolysis treatment makes these engineered
biochars attractive as P sources for crops and presents an attractive solution to mitigate in-field sugarcane
residue buring |
Publication
Journal Publication
ไทย