土壤有机物原始化:pH值的影响
Chaoqun Wang1,2,3, Yakov Kuzyakov4,5
1Biogeochemistry of Agroecosystems, University of Göttingen, Göttingen, Germany.
Global change biology
|June 1, 2024
概括
土壤pH显著影响土壤有机物 (SOM) 分解,这是全球碳循环中的一个关键过程. 最佳的pH值范围 (5.5-7.5) 增强了原始效应 (PEs),而极端的pH值可以抑制它们.
科学领域:
- 土壤科学 土壤科学
- 生物地质化学生物地质化学
- 微生物生态学 微生物生态学
背景情况:
- 对土壤有机物 (SOM) 分解的原始效应 (PEs) 对全球碳 (C) 循环至关重要.
- 土壤pH值是PE的主要决定因素,影响微生物群落,SOM稳定性和生物地球化学过程.
研究的目的:
- 批判性地审查由土壤pH影响的PE的先决条件和机制.
- 评估全球变化对依赖pH的PE的影响.
主要方法:
- 文献综述侧重于pH介导的原始化效应.
- 分析微生物群落的组成,酶活动和SOM稳定机制在不同的pH水平.
- 评估土壤酸化对PE的短期和长期影响.
主要成果:
- 在pH值5.57.5的土壤中观察到最高的PEs,特别是在pH值6.5左右,正的PEs可能比基线SOM分解高20倍.
- 低分子量有机化合物主要在轻微酸性土壤中触发PE.
- 负PE发生在pH值<4.5或>7时,表明微生物条件不理想或特定的SOM稳定.
- 短期的酸化 (例如,在树根球中) 通过矿物-SOM复合,SOM氧化,酶脱聚合和营养物质的可用性影响PE.
- 肥和土地利用强化降低了土壤的pH值,从而增加了PEs.
结论:
- 土壤的pH值是一个关键的,但经常被忽视的,控制SOM分解和PE的因素.
- 微生物代谢因短期的微生物代谢变化和长期的微生物群落适应pH变化而受到PEs的调节.
- 了解pH-PE关系对于预测碳循环对全球变化的反应至关重要.
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