Microbial necromass in cropland soils: A global meta‐analysis of management effects

作者：Ranran Zhou, Yuan Liu, Jennifer A. J. Dungait, Amit Kumar, Jinsong Wang, Lisa K. Tiemann, Fusuo Zhang, Yakov Kuzyakov, Jing Tian · 发表于：Global Change Biology · 年份：2023 · DOI：10.1111/gcb.16613 · 被引用次数：218 · 研究领域：Soil Carbon and Nitrogen Dynamics、Mycorrhizal Fungi and Plant Interactions、Composting and Vermicomposting Techniques

Microbial necromass is a large and persistent component of soil organic carbon (SOC), especially under croplands. The effects of cropland management on microbial necromass accumulation and its contribution to SOC have been measured in individual studies but have not yet been summarized on the global scale. We conducted a meta-analysis of 481-paired measurements from cropland soils to examine the management effects on microbial necromass and identify the optimal conditions for its accumulation. Nitrogen fertilization increased total microbial necromass C by 12%, cover crops by 14%, no or reduced tillage (NT/RT) by 20%, manure by 21%, and straw amendment by 21%. Microbial necromass accumulation was independent of biochar addition. NT/RT and straw amendment increased fungal necromass and its contribution to SOC more than bacterial necromass. Manure increased bacterial necromass higher than fungal, leading to decreased ratio of fungal-to-bacterial necromass. Greater microbial necromass increases after straw amendments were common under semi-arid and in cool climates in soils with pH <8, and were proportional to the amount of straw input. In contrast, NT/RT increased microbial necromass mainly under warm and humid climates. Manure application increased microbial necromass irrespective of soil properties and climate. Management effects were especially strong when applied during medium (3-10 years) to long (10+ years) periods to soils with larger initial SOC contents, but were absen...