Abstract A large part of crop nutrient uptake occurs through the interaction of roots with symbiotic arbuscular mycorrhizal fungi (AMF). However, it is still an open question how straw management and earthworm activity affect AMF community structure and their nitrogen-transferring function in wheat. A split-plot field experiment was conducted to address this question. Three straw management regimes including different tillage treatments (no-till with no straw, NTNS; rotary tillage with straw return, RTSR and ditch-buried straw return, DBSR), and two earthworm treatments (no earthworm, −E; and earthworm addition, +E) were conducted. The AMF community structure in the wheat roots was characterized with high-throughput sequencing, and its function in terms of N acquisition was measured with 15N isotope tracing through hyphal in-growth cores. Our results showed that both the DBSR and RTSR treatments significantly changed AMF community composition and enhanced the mycorrhiza-mediated plant N uptake when compared to NTNS. The effect of earthworm activity on AMF community composition and mycorrhiza-mediated N uptake strongly depended on the straw management regimes. While earthworm presence increased AMF dominance (+32.9%) and mycorrhizal N uptake (+2.05-fold) under straw removal, they decreased AMF dominance (−30.4% and −41.9% respectively) and mycorrhizal N uptake (−37.3% and −34.3% respectively) under both DBSR and RTSR treatments in comparison with the absence of earthworms. It is concluded that straw addition shifts the AMF community structure and increases N uptake by the host plants; and that the effect of earthworms on AMF community structure and functioning depends on the straw management regime. The results suggest that straw management and its interaction with earthworms can affect mycorrhiza-mediated plant N uptake, possibly through altering some dominant AMF taxa.

中文翻译：

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只有在免耕和秸秆去除条件下，蚯蚓活动才能增加小麦菌根氮的吸收

摘要 作物养分吸收的很大一部分是通过根与共生丛枝菌根真菌 (AMF) 的相互作用发生的。然而，秸秆管理和蚯蚓活动如何影响小麦 AMF 群落结构及其氮转移功能仍然是一个悬而未决的问题。为了解决这个问题，进行了裂区田间试验。三种秸秆管理方案，包括不同的耕作处理（免耕无秸秆，NTNS；秸秆还田旋耕，RTSR 和沟埋秸秆还田，DBSR）和两种蚯蚓处理（无蚯蚓，-E；和蚯蚓添加， +E) 进行。小麦根部的 AMF 群落结构通过高通量测序进行表征，其在 N 获取方面的功能通过菌丝向内生​​长核心进行 15N 同位素示踪测量。我们的结果表明，与 NTNS 相比，DBSR 和 RTSR 处理显着改变了 AMF 群落组成并增强了菌根介导的植物 N 吸收。蚯蚓活动对 AMF 群落组成和菌根介导的 N 吸收的影响在很大程度上取决于秸秆管理制度。虽然蚯蚓的存在增加了秸秆去除下的 AMF 优势（+32.9%）和菌根 N 吸收（+2.05 倍），但它们降低了 AMF 优势（分别为 -30.4% 和 -41.9%）和菌根 N 吸收（-37.3% 和 -34.3 %）与没有蚯蚓的情况相比，在 DBSR 和 RTSR 处理下。结论是秸秆添加改变了AMF群落结构，增加了寄主植物对氮的吸收；蚯蚓对 AMF 群落结构和功能的影响取决于秸秆管理制度。结果表明，秸秆管理及其与蚯蚓的相互作用可以影响菌根介导的植物氮吸收，可能是通过改变一些优势 AMF 分类群。