TY - JOUR

T1 - A multi-technique approach to assess the fate of biochar in soil and to quantify its effect on soil organic matter composition

AU - Paetsch, Lydia

AU - Mueller, Carsten W.

AU - Rumpel, Cornelia

AU - Angst, Šárka

AU - Wiesheu, Alexandra C.

AU - Girardin, Cyril

AU - Ivleva, Natalia P.

AU - Niessner, Reinhard

AU - Kögel-Knabner, Ingrid

PY - 2017/10

Y1 - 2017/10

N2 - Differentiation of biochar and native soil organic matter (SOM) is required to assess the effect of biochar amendment on in-situ changes of SOM. Therefore, we used C4 biochar produced at high temperature (1200 °C) by gasification (BCGS) and measured the 13C abundance of density and particle size fractions. We quantified the BCGS effects on distinct native C3-SOM pools of a grassland topsoil one year after BCGS amendment. The chemical composition was analyzed with solid-state 13C CPMAS NMR, whereas information on the nanostructure of BCGS were obtained by Raman microspectroscopy measurements. Our aim was to assess BCGS induced chemical changes of SOM and physical fractions and to validate the accuracy of BCGS detection by 13C NMR spectroscopy. Quantification by isotopic measurements and 13C NMR spectroscopy for aromatic C yielded similar estimates of BC in soils. Of the total BCGS, 52% were recovered as free particulate organic matter (POM) and 33% were located in aggregated soil structures isolated as occluded POM particles. Around 4% of the total BCGS was detected in the clay fraction. After one year of field exposure, the surface of the BCGS particles decreased in unordered graphitic-like structures. The higher ordered BC residue is supposed to be more recalcitrant. The native SOC stock increase (p = 0.06, n = 4) in the clay fraction indicated increased sequestration of organic matter as mineral-bound SOM due to BCGS amendment. With respect to soil functionality, the BCGS amendment induced a tremendous shift from a soil system dominated by organo-mineral associations to POM−dominated OC storage, resulting in increased soil air capacity.

AB - Differentiation of biochar and native soil organic matter (SOM) is required to assess the effect of biochar amendment on in-situ changes of SOM. Therefore, we used C4 biochar produced at high temperature (1200 °C) by gasification (BCGS) and measured the 13C abundance of density and particle size fractions. We quantified the BCGS effects on distinct native C3-SOM pools of a grassland topsoil one year after BCGS amendment. The chemical composition was analyzed with solid-state 13C CPMAS NMR, whereas information on the nanostructure of BCGS were obtained by Raman microspectroscopy measurements. Our aim was to assess BCGS induced chemical changes of SOM and physical fractions and to validate the accuracy of BCGS detection by 13C NMR spectroscopy. Quantification by isotopic measurements and 13C NMR spectroscopy for aromatic C yielded similar estimates of BC in soils. Of the total BCGS, 52% were recovered as free particulate organic matter (POM) and 33% were located in aggregated soil structures isolated as occluded POM particles. Around 4% of the total BCGS was detected in the clay fraction. After one year of field exposure, the surface of the BCGS particles decreased in unordered graphitic-like structures. The higher ordered BC residue is supposed to be more recalcitrant. The native SOC stock increase (p = 0.06, n = 4) in the clay fraction indicated increased sequestration of organic matter as mineral-bound SOM due to BCGS amendment. With respect to soil functionality, the BCGS amendment induced a tremendous shift from a soil system dominated by organo-mineral associations to POM−dominated OC storage, resulting in increased soil air capacity.

KW - C CPMAS NMR spectroscopy

KW - Carbon sequestration

KW - Density fractionation

KW - Equivalent soil mass

KW - Isotopic mixing model

KW - Molecular mixing model

KW - Native SOM

KW - Raman microspectroscopy

KW - Stable isotope

U2 - 10.1016/j.orggeochem.2017.06.012

DO - 10.1016/j.orggeochem.2017.06.012

M3 - Journal article

AN - SCOPUS:85029000793

VL - 112

SP - 177

EP - 186

JO - Organic Geochemistry

JF - Organic Geochemistry

SN - 0146-6380

ER -