TITLE:
Short-Term Field Decomposition and Physico-Chemical Transformation of Jatropha Pod Biochar in Acidic Mineral Soil
AUTHORS:
Cheah Poh Meng, Ahmad Husni Mohd Hanif, Samsuri Abd Wahid, Luqman Chuah Abdullah
KEYWORDS:
Litter Bag Study, Redox, FTIR, NMR, Hyperbolic Decay Model
JOURNAL NAME:
Open Journal of Soil Science,
Vol.4 No.7,
July
10,
2014
ABSTRACT: Details
regarding field decomposition and transformation of biochar in Malaysia are
scarce. The objectives of this study were to investigate the physico-chemical
changes experienced by Jatropha pod biochar (JPB) in acidic mineral soil under
field condition. Elemental composition was determined using CHNS-O analyzer and
surface area with Brunauer-Emmett-Teller (BET) method. The JPB surface
chemistry and structure were studied using the Fourier Transform Infrared (FTIR) spectroscopy and 13C solid state Nuclear Magnetic Resonance (NMR) spectroscopy, respectively. The
JPB short-term decomposition was investigated by using a litter bag study and
decomposition data were best fitted by a hyperbolic decay model compared to an
exponential decay model because no significant dry weight loss was detected
after 4 months. Two phases (volatile and near stagnant) were detected for JPB
field decomposition. The volatile phase was due to rapid loss of labile
fraction such as carbohydrate during the initial 4 months. The near stagnant
phase was probably due to adsorption of organic matter and soil minerals. The
JPB was fragmented into smaller pieces, encouraging surface adsorption. Redox
reaction was prominent as shown by the production of hydroxyl, carboxylic and
phenolic functional groups. The JPB became more recalcitrant after 12 months of
application to the soils.