Rising atmospheric carbon dioxide [CO₂] is a main climate change driver, and soil respiration is the most relevant contributor to ecosystem respiration. However, the soil microbiome and respiration responses of semiarid agroecosystems under elevated [CO₂] (eCO₂) conditions must be better understood. In particular, peanut agroecosystems host rhizobia and arbuscular mycorrhizal fungi (AMF) associations. Here, we sought to address the following questions: a) Does eCO₂ conditions (650 µmol CO₂ m⁻² s⁻¹, +250 µmol CO₂ m⁻² s⁻¹, aCO₂, control) alter soil chemical properties, soil microbial community size and composition, soil respiration, and β-Glucosidase activity? b) Are these responses influenced by transient water deficit periods? We conducted this study in a typical West Texas semiarid region (no well-watered treatment and drought was not an experimental factor) during two consecutive growing seasons (May-Oct). We induced the atmospheric CO₂ enrichment using field-installed Canopy Evapotranspiration and Assimilation (CETA) systems. Our results showed no consistent significant changes in soil moisture, C: N ratio, total soil microbial EL-FAME abundance, or β-Glucosidase activity. However, we found that eCO₂ increased soil temperature (+1 °C), AMF abundance (EL-FAME marker, +49%), and soil respiration (+82%). Our findings suggest that in future semiarid climates, peanut agroecosystems may experience: 1) increased soil metabolic activity as a result of increased autotrophic respiration; 2) increased AMF, which could further facilitate plant nutrient and water uptake; and 3) minimal change in the total size of the microbial community and C cycling enzyme activity during the growing season. In this manuscript, we demonstrated that soil respiration and temperature could be indicators of ecosystem productivity and climate feedback. Furthermore, soil organic carbon and AMF were good indicators of poor nutrient soil ecosystem transitional health across well-watered and water-deficit cycles. This study will increase our understanding of how these changes will affect soil ecology and climate feedback and will provide new insight into the peanut agroecosystem carbon source/sink functioning and productivity in future climates.

大气中二氧化碳 [CO ₂ ] 的增加是气候变化的主要驱动因素，而土壤呼吸是生态系统呼吸最相关的贡献者。然而，必须更好地了解[CO ₂ ] (eCO ₂ )升高条件下半干旱农业生态系统的土壤微生物组和呼吸响应。特别是，花生农业生态系统寄主根瘤菌和丛枝菌根真菌 (AMF) 协会。在这里，我们试图解决以下问题：a) eCO ₂条件（650 µmol CO ₂ m ⁻² s ⁻¹ , +250 µmol CO ₂ m ⁻² s ⁻¹ , aCO ₂, 控制）改变土壤化学性质、土壤微生物群落大小和组成、土壤呼吸和 β-葡萄糖苷酶活性？b) 这些反应是否受到短暂缺水期的影响？我们在连续两个生长季节（5 月至 10 月）期间在典型的西德克萨斯半干旱地区（没有充分浇水处理，干旱不是实验因素）进行了这项研究。我们使用现场安装的 Canopy Evapotranspiration and Assimilation (CETA) 系统诱导了大气中 CO _{2 的}富集。我们的结果表明，土壤水分、C:N 比、土壤微生物 EL-FAME 总丰度或 β-葡萄糖苷酶活性没有发生一致的显着变化。然而，我们发现 eCO ₂增加土壤温度 (+1 °C)、AMF 丰度（EL-FAME 标记，+49%）和土壤呼吸（+82%）。我们的研究结果表明，在未来的半干旱气候中，花生农业生态系统可能会经历：1）自养呼吸增加导致土壤代谢活动增加；2) 增加AMF，进一步促进植物养分和水分的吸收；3) 在生长季节，微生物群落的总规模和 C 循环酶活性的变化最小。在这份手稿中，我们证明了土壤呼吸和温度可以作为生态系统生产力和气候反馈的指标。此外，土壤有机碳和 AMF 是良好的营养不良土壤生态系统过渡健康的良好指标，跨越充足的水分和缺水循环。