Soil organic matter priming: The pH effects

文献类型： 外文期刊

第一作者： Wang, Chaoqun

作者： Wang, Chaoqun;Wang, Chaoqun;Wang, Chaoqun;Kuzyakov, Yakov;Kuzyakov, Yakov

作者机构：

关键词： exoenzyme; iron and manganese reduction; microbial community activity; plant litter input; soil acidification; soil organic matter stabilization

期刊名称：GLOBAL CHANGE BIOLOGY （ 影响因子：11.6； 五年影响因子：12.3 ）

ISSN： 1354-1013

年卷期： 2024 年 30 卷 6 期

页码：

收录情况： SCI

摘要： Priming of soil organic matter (SOM) decomposition by microorganisms is a key phenomenon of global carbon (C) cycling. Soil pH is a main factor defining priming effects (PEs) because it (i) controls microbial community composition and activities, including enzyme activities, (ii) defines SOM stabilization and destabilization mechanisms, and (iii) regulates intensities of many biogeochemical processes. In this critical review, we focus on prerequisites and mechanisms of PE depending on pH and assess the global change consequences for PE. The highest PEs were common in soils with pH between 5.5 and 7.5, whereas low molecular weight organic compounds triggered PE mainly in slightly acidic soils. Positive PEs up to 20 times of SOM decomposition before C input were common at pH around 6.5. Negative PEs were common at soil pH below 4.5 or above 7 reflecting a suboptimal environment for microorganisms and specific SOM stabilization mechanisms at low and high pH. Short-term soil acidification (in rhizosphere, after fertilizer application) affects PE by: mineral-SOM complexation, SOM oxidation by iron reduction, enzymatic depolymerization, and pH-dependent changes in nutrient availability. Biological processes of microbial metabolism shift over the short-term, whereas long-term microbial community adaptations to slow acidification are common. The nitrogen fertilization induced soil acidification and land use intensification strongly decrease pH and thus boost the PE. Concluding, soil pH is one of the strongest but up to now disregarded factors of PE, defining SOM decomposition through short-term metabolic adaptation of microbial groups and long-term shift of microbial communities.

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