/ J. Cui, Z. K. Zhu, X. L. Xu [et al.] // Soil Biol. Biochem. - 2020. -
Vol. 142. - Ст. 107720,
DOI 10.1016/j.soilbio.2020.107720. - Cited References:80. - The study was supported by the National Key Research and Development Program of China (2017YFD0800104), the National Natural Science Foundation of China (41430860, 41771337, 41977093 and 31872695), State Key Laboratory of Organic Geochemistry, GIGCAS (SKLOG-201728), Hunan Province Base for Scientific and Technological Innovation Cooperation (2018WK4012), the Youth Innovation Team Project of Institute of Subtropical Agriculture, Chinese Academy of Sciences (2017QNCXTD_GTD), NSFC-RFBR joint project (N 19-54-53026) and Innovation Groups of National Natural Science Foundation of Hunan Province (2019JJ10003). We thank the Public Service Technology Center, Institute of Subtropical Agriculture, Chinese Academy of Sciences for technical assistance. The publication was supported by the Government Program of Competitive Growth of Kazan Federal University and with the support of the "RUDN University program 5-100."
. - ISSN 0038-0717
РУБ Soil Science
Аннотация: The impact of increasing amounts of labile C input on priming effects (PE) on soil organic matter (SOM) mineralization remains unclear, particularly under anoxic conditions and under high C input common in microbial hotspots. PE and their mechanisms were investigated by a 60-day incubation of three flooded paddy soils amended with(13)C-labeled glucose equivalent to 50-500% of microbial biomass C (MBC). PE (14-55% of unamended soil) peaked at moderate glucose addition rates (i.e., 50-300% of MBC). Glucose addition above 300% of MBC suppressed SOM mineralization but intensified microbial N acquisition, which contradicted the common PE mechanism of accelerating SOM decomposition for N-supply (frequently termed as "N mining"). Particularly at glucose input rate higher than 3 g kg(-1) (i.e., 300-500% of MBC), mineral N content dropped on day 2 close to zero (1.1-2.5 mg N kg(-1)) because of microbial N immobilization. To cope with the N limitation, microorganisms greatly increased N-acetyl glucosaminidase and leucine aminopeptidase activities, while SOM decomposition decreased. Several discrete peaks of glucose-derived CO2 (contributing >80% to total CO2) were observed between days 13-30 under high glucose input (300-500% of MBC), concurrently with CH4 peaks. Such CO2 dynamics was distinct from the common exponential decay pattern, implicating the recycling and mineralization of C-13-enriched microbial necromass driven by glucose addition. Therefore, N recycling from necromass was hypothesized as a major mechanism to alleviate microbial N deficiency without SOM priming under excess labile C input. Compound-specific C-13-
PLFA confirmed the redistribution of glucose-derived C among microbial groups, i.e., necromass recycling. Following glucose input, more than 4/5 of total C-13-
PLFA was in the gram-negative and some non-specific bacteria, suggesting these microorganisms as r-strategists capable of rapidly utilizing the most labile C. However, their C-13-
PLFA content decreased by 70% after 60 days, probably as a result of death of these r-strategists. On the contrary, the C-13-
PLFA in gram-positive bacteria, actinomycetes and fungi (K-strategists) was initially minimal but increased by 0.5-5 folds between days 2 and 60. Consequently, the necromass of dead r-strategists provided a high-quality C-N source to the K-strategists. We conclude that under severe C excess, N recycling from necromass is a much more efficient microbial strategy to cover the acute N demand than N acquisition from the recalcitrant SOM.
WOS Держатели документа: Chinese Acad Sci, Inst Subtrop Agr, Key Lab Agroecol Proc Subtrop Reg, Changsha 410125, Hunan, Peoples R China.
Chinese Acad Sci, Inst Subtrop Agr, Changsha Res Stn Agr & Environm Monitoring, Changsha 410125, Hunan, Peoples R China.
Chinese Acad Sci, State Key Lab Organ Geochem, Guangzhou Inst Geochem, Gongdong 510640, Peoples R China.
Yancheng Teachers Univ, Jiangsu Prov Key Lab Bioresources Coastal Saline, Jiangsu Coastal Biol Agr Synthet Innovat Ctr, Yancheng 224002, Peoples R China.
Chinese Acad Sci, Key Lab Ecosyst Network Observat & Modeling, Inst Geog Sci & Nat Resources Res, Beijing, Peoples R China.
Bangor Univ, Sch Environm Nat Resources & Geog, Bangor LL57 2UW, Gwynedd, Wales.
Univ Gottingen, Dept Agr Soil Sci, Dept Soil Sci Temperate Ecosyst, Gottingen, Germany.
Kazan Fed Univ, Inst Environm Sci, Kazan 420049, Russia.
RUDN Univ, Agrotechnol Inst, Moscow 117198, Russia.
Univ La Frontera, Dept Ciencias Quim & Recursos Nat, Temuco, Chile.
RAS, SB, VN Sukachev Inst Forest, Krasnoyarsk 660036, Russia.
Доп.точки доступа: Cui, Jun; Zhu, Zhenke; Xu, Xingliang; Liu, Shoulong; Jones, Davey L.; Kuzyakov, Yakov; Shibistova, Olga; Wu, Jinshui; Ge, Tida; National Key Research and Development Program of China [2017YFD0800104]; National Natural Science Foundation of ChinaNational Natural Science Foundation of China [41430860, 41771337, 41977093, 31872695]; State Key Laboratory of Organic Geochemistry, GIGCAS [SKLOG-201728]; Hunan Province Base for Scientific and Technological Innovation Cooperation [2018WK4012]; Youth Innovation Team Project of Institute of Subtropical Agriculture, Chinese Academy of Sciences [2017QNCXTD_GTD]; NSFC-RFBR joint project [N 19-54-53026]; Innovation Groups of National Natural Science Foundation of Hunan Province [2019JJ10003]; Government Program of Competitive Growth of Kazan Federal University; RUDN University program 5-100
