Zhang et al. (2024): Soil organic carbon increase via microbial assimilation or soil protection against the priming effect is mediated by the availability of soil N relative to input C

Futao Zhang, Qianqian Wang, Yueling Zhang, Shuihong Yao, Qinhua Wang, Georges Ndzana, Ute Hamer, Yakov Kuzyakov, Bin Zhang IN: Geoderma, 444, 116861, https://doi.org/10.1016/j.geoderma.2024.116861

Labile C inputs into soils will be partially transformed into soil organic carbon (SOC) through microbial assimilation or physicochemical protection as such mineral-organic interactions and soil aggregation. The C inputs may stimulate the decomposition of native SOC, inducing a phenomenon known as the priming effect. Increasing C inputs may increase SOC content, yet the relative role of these mechanisms in controlling the magnitudes of SOC increase among soils remains unclear. Four soils differing in microbiology and N content were incubated with ¹³C-labeled glucose at the amounts of 0.5 (G_0.5), 1.0 (G_1.0), and 2.0 (G_2.0) g C kg⁻¹ soil for 48 days. The objectives of this study were 1) to quantify the fates of added glucose-C, the priming effect, and the changes in SOC and mineral N contents after the incubation, and 2) to identify the main mechanisms for SOC increase with the increased amount of C input and the effects of initial soil N availability and microbial composition.

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