Zheng Xiang, An Zhengfeng, Cao Minmin, Wu Fan, Guan Xin, Chang Scott X, Liu Shenglong, Jiang Jiang
Collaborative Innovation Center of Sustainable Forestry in Southern China of Jiangsu Province, Key Laboratory of Soil and Water Conservation and Ecological Restoration in Jiangsu Province, Nanjing Forestry University, Nanjing 210037, China; Department of Renewable Resources, 442 Earth Science Building, University of Alberta, Edmonton T6G 2E3, Canada.
Department of Renewable Resources, 442 Earth Science Building, University of Alberta, Edmonton T6G 2E3, Canada.
Sci Total Environ. 2022 Dec 15;852:158309. doi: 10.1016/j.scitotenv.2022.158309. Epub 2022 Aug 26.
Arbuscular mycorrhizal fungi (AMF) are widespread in subtropical forests and play a crucial role in belowground carbon (C) dynamics. Nitrogen (N) deposition or fertilization may affect AMF and thus the flux of plant-derived C back to the atmosphere via AMF hyphae. However, the contribution of AMF hyphal respiration to soil respiration and the response AMF hyphal respiration to increased soil N availability remain unknown. We studied the effect of N fertilization (0, 50, 100 and 200 kg N ha yr) on AMF hyphal respiration, root respiration and heterotrophic (microbial) respiration in a subtropical Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) plantation. We found that short-term N addition did not affect root, AMF hyphal and soil microbial respiration, because soil N availability and extraradical hyphae were not affected by N addition. The AMF hyphal respiration contributed 12 % of total soil respiration and 25 % of the autotrophic respiration. Root, AMF hyphal and soil microbial respiration were positively correlated with soil moisture content but not with soil temperature. Our results indicate that AMF hyphal respiration is a large source of soil respiration, and should be considered in partitioning soil respiration into different components in future studies to better understand the response of soil respiration to N addition.
丛枝菌根真菌（AMF）在亚热带森林中广泛分布，在地下碳（C）动态中起着关键作用。氮（N）沉降或施肥可能会影响AMF，进而影响植物源碳通过AMF菌丝返回大气的通量。然而，AMF菌丝呼吸对土壤呼吸的贡献以及AMF菌丝呼吸对土壤有效氮增加的响应仍不清楚。我们研究了施肥（0、50、100和200 kg N ha⁻¹ yr⁻¹）对中国亚热带杉木（Cunninghamia lanceolata (Lamb.) Hook）人工林中AMF菌丝呼吸、根系呼吸和异养（微生物）呼吸的影响。我们发现，短期施氮并未影响根系、AMF菌丝和土壤微生物呼吸，因为土壤有效氮和根外菌丝不受施氮影响。AMF菌丝呼吸占土壤总呼吸的12%，占自养呼吸的25%。根系、AMF菌丝和土壤微生物呼吸与土壤水分含量呈正相关，但与土壤温度无关。我们的结果表明，AMF菌丝呼吸是土壤呼吸的一个重要来源，在未来研究中将土壤呼吸划分为不同组分时应予以考虑，以便更好地理解土壤呼吸对施氮的响应。
