Rice (Oryza sativa L) plantation affects the stability of biochar in paddy soil

Abstract

Conversion of rice straw into biochar for soil amendment appears to be a promising method to increase long-term carbon sequestration and reduce greenhouse gas (GHG) emissions. The stability of biochar in paddy soil, which is the major determining factor of carbon sequestration effect, depends mainly on soil properties and plant functions. However, the influence of plants on biochar stability in paddy soil remains unclear. In this study, bulk and surface characteristics of the biochars incubated without rice plants were compared with those incubated with rice plants using a suite of analytical techniques. Results showed that although rice plants had no significant influence on the bulk characteristics and decomposition rates of the biochar, the surface oxidation of biochar particles was enhanced by rice plants. Using 13C labeling we observed that rice plants could significantly increase carbon incorporation from biochar into soil microbial biomass. About 0.047% of the carbon in biochar was incorporated into the rice plants during the whole rice growing cycle. These results inferred that root exudates and transportation of biochar particles into rice plants might decrease the stability of biochar in paddy soil. Impact of plants should be considered when predicting carbon sequestration potential of biochar in soil systems.

Interactions between biochar and soil organic carbon decomposition: Effects of nitrogen and low molecular weight carbon compound addition

“…A previous study reported that fresh C supply would decrease stability of old SOC in deep soil layers through priming (Fontaine et al, 2007). A recent study reported increased biochar-C incorporation into soil microbial biomass with rice plants (Wu et al, 2015), but it was uncertain whether this positive response was related with LMW-C exudates from rice roots. LMW-Cs support microbial growth and account for as much as 30% of total soil respiration ( van Hees et al, 2005), which play both a direct and an indirect role in the formation, decomposition, and stabilization of soil C storage (de Graaff et al, 2010).…”

Biochar loaded chitosan/gelatin/poly(ethylene glycol) biocomposite beads: Morphological, thermal and swelling properties

“…The FTIR spectra of the biochar peak at 1580 cm -1 which corresponded to the C=O stretching and aromatic C=C vibrations [18]. The peaks at 1444 cm -1 aliphatic C-H groups and C=C stretching and 882 cm -1 were related to aromatic C-H bending, respectively [19,20]. The peak at 1080 cm -1 could be related to the C-O stretching [21].…”

“…The last step of the bead samples was related to the burning of the pyrolysis product which was formed during analysis in the N2 atmosphere. FTIR spectrum of the biochar involves peaks related to the C-O group (1111 cm -1 and 1021 cm -1 ) and amine group (1592 cm -1 and 1416 cm -1 ) [18][19][20]. Before 600°C, the TGA analysis was carried out in the inert atmosphere, because neat bead undergoes both decomposition and pyrolysis reaction while biochar does not decompose.…”

Biochar efficiency in pesticides sorption as a function of production variables—a review

“…The biochar decomposition can give the entrapped portion of chemicals exposure to degradation. Therefore, the release of entrapped pesticide from saturated biochar is dependent on the biochar properties and its degree of recalcitrance, the properties of the organic substance, and the environmental conditions (Spokas 2010;Wu et al 2015).…”