Abstract Agricultural soil is the most important carbon (C) pool on the Earth's surface and is also a source or sink of greenhouse gases. The C cycle is one of the important biogeochemical processes in the agroecosystem and requires microorganisms to participate in many of the important C cycling pathways, such as C fixation, C degradation, and methane metabolism. Insight into the functions of microbial communities in the C cycle can provide a better understanding of the response and feedback of soil microbes with respect to global climate change. The microarray GeoChip 5.0 was used in this study to detect the specific genes linking C cycling and soil microbial-mediated processes and to evaluate the abundance, diversity and similarity of the detected genes responding to different nitrogen (N) application levels under intercropping treatment. Our results indicated that compositional changes in soil microbial communities elicited by N input have functional implications for C cycling and storage in agroecosystems. We further identified a sugarcane (Saccharum officinarum) field as a C sink in this intercropping system, in which sugarcane/soybean (Glycine max) (1:2) strip intercropping (SB2) at the N1 application rate (SB2-N1) had the largest C sequestration potential and net C balance among all the treatments. Most of the functional genes involved in C cycling with regards to fixation and degradation were separately identified after 4 years of N fertilization and intercropping treatments, and environmental factors were central in shaping the functional gene structure related to the C cycles. Overall, our results suggested that reduced N application combined with intercropping treatment mediates ecosystem functions and may have profound feedback effects on global climate change.

中文翻译：

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GeoChip 5.0确定的华南地区氮输入减少的甘蔗和大豆间作系统土壤碳循环

摘要 农业土壤是地球表面最重要的碳（C）库，也是温室气体的源或汇。C循环是农业生态系统中重要的生物地球化学过程之一，需要微生物参与许多重要的C循环途径，如C固定、C降解和甲烷代谢。深入了解碳循环中微生物群落的功能可以更好地了解土壤微生物对全球气候变化的响应和反馈。本研究使用微阵列 GeoChip 5.0 检测连接 C 循环和土壤微生物介导过程的特定基因，并评估检测到的基因在间作处理下响应不同氮 (N) 应用水平的丰度、多样性和相似性。我们的结果表明，氮输入引起的土壤微生物群落的组成变化对农业生态系统中的碳循环和储存具有功能影响。我们进一步将甘蔗（Saccharum officinarum）田确定为该间作系统中的碳汇，其中甘蔗/大豆（Glycine max）（1:2）条带间作（SB2）在 N1 施用率（SB2-N1）下具有所有处理中最大的 C 封存潜力和净 C 平衡。经过 4 年的施氮和间作处理后，大多数参与 C 循环的功能基因在固定和降解方面被单独鉴定，环境因素是塑造与 C 循环相关的功能基因结构的核心。全面的，