|ZHANG, YUELING - Chinese Academy Of Agricultural Sciences
|YAO, SHUIHONG - Chinese Academy Of Agricultural Sciences
|MAO, JINGDONG - Old Dominion University
|Olk, Daniel - Dan
|CAO, XIAOYAN - Old Dominion University
|ZHANG, BIN - Chinese Academy Of Agricultural Sciences
Submitted to: Soil Biology and Biochemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/12/2015
Publication Date: 6/1/2015
Citation: Zhang, Y., Yao, S., Mao, J., Olk, D.C., Cao, X., Zhang, B. 2015. Chemical composition of organic matter in a deep soil changed with a positive priming effect due to glucose addition as investigated by 13C NMR spectroscopy. Soil Biology and Biochemistry. 85:137-144.
Interpretive Summary: Carbon contributes to several favorable soil processes, including nutrient availability, water infiltration, and biological activity. The addition of new carbon into soil might cause faster decomposition of carbon already present in the soil by promoting microbial activity. We measured changes in both the amounts and types of stable carbon in a subsoil after a sugar was added to promote microbial activity. This work demonstrates the complexity of managing stable soil carbon and its interactions with microbial activity. It will benefit researchers who study the factors of carbon stability in soil or the types of carbon in soil and land managers who strive to maximize carbon content in soil.
Technical Abstract: Fresh organic carbon becomes more accessible to subsoil following losses of surface soil or deep incorporation of crop residues, which can cause the priming effect and influence the quality and quantity of soil organic C (SOC) in subsoil. Chemical compositions of SOC in subsoil (1.0-1.2 m) without (G0) and with (G0.4) addition of 13C-labelled glucose (0.4 g C kg-1 soil) were investigated during a 31-d incubation with solid-state 13C cross polarization/total sideband suppression (13C-CP/TOSS) and CP/TOSS with dipolar dephasing nuclear magnetic resonance (NMR) techniques. No glucose remained in the soil after 21 days of incubation, 48% was mineralized into CO2 emission and 52% was incorporated into SOC. The native SOC was decomposed by 0.23% more in G0.4 than in G0. Both labile and recalcitrant organic compounds in SOC changed during the incubation, but in different manners in G0 and G0.4. The -CH2n- abundance in G0 did not change during the incubation, but in G0.4 it decreased from Day 0 to Day 21 and then increased from Day 21 to Day 31, suggesting shifts in soil microbial communities only in G0.4. In G0 the abundances of ketones/aldehydes and nonpolar alkyl C increased, but those of aromatic C-C and protonated O-alkyl C (OCH) decreased. In G0.4, the abundances of NCH and protonated O alkyl C (OCH) increased, but those of nonpolar alkyl C and nonprotonated aromatic C-O and ketones/aldehydes decreased. Such inconsistent changes in recalcitrant compounds between G0 and G0.4 indicated that glucose addition likely primed the decomposition of aromatic C-O and suppressed the formation of ketones/aldehydes. We have demonstrated for the first time that the priming effect due to glucose addition caused changes in both labile and recalcitrant structures of native SOC.