Increased food demand and water scarcity require the efficient use of agricultural water. Deficit irrigation (DI) can reduce water use with relatively small impacts to crop yield. However, the effects of DI‐associated water stress on root and soil properties remain poorly understood. We examined the impact of water stress via DI on maize (Zea mays L.) root growth, soil microbial community composition, soil aggregation, and soil organic C (SOC) concentrations at two depths (0–20 and 40–60 cm) after 4 yr of treatment implementation. Water stress during the late vegetative stage increased root growth at both soil depths in all stress treatments (significantly at 40–60 cm) but led to lower microbial biomass, assessed using phospholipid fatty acid (PLFA) analysis. Moreover, water stress led to a lower abundance of arbuscular mycorrhizal fungi markers in the drier treatments. After 4 yr of treatment, we did not find significant differences in SOC. However, a trend towards higher SOC and greater root biomass in the driest treatment indicated the potential to build soil C in deeper soil layers with larger root C inputs. Soil aggregation was generally greater in deeper soils (average increase of 24%). Overall, the observations in this study indicate that DI alters root growth and soil microbial community structure with the potential to impact SOC storage and overall agroecosystem function beyond the 4‐yr timeframe considered in this study.

中文翻译：

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亏缺灌溉驱动玉米根系分布和土壤微生物群落，影响土壤碳动态

粮食需求增加和缺水需要有效利用农业用水。亏缺灌溉（DI）可以减少用水，对作物产量的影响相对较小。但是，与DI相关的水分胁迫对根和土壤特性的影响仍然知之甚少。我们研究了通过DI处理的水分胁迫对玉米（Zea maysL.）实施4年后，在两个深度（0–20和40–60 cm）的根部生长，土壤微生物群落组成，土壤聚集和土壤有机碳（SOC）浓度。在所有营养处理中，植物生长后期的水分胁迫均会增加两种土壤深度的根系生长（明显在40-60 cm），但使用磷脂脂肪酸（PLFA）分析评估，导致微生物生物量降低。此外，在干旱处理中，水分胁迫导致丛枝菌根真菌标记物的含量较低。治疗4年后，我们没有发现SOC的显着差异。但是，在最干燥的处理中，SOC升高和根系生物量增加的趋势表明，在根系C投入较大的更深土壤层中建立土壤C的潜力。在较深的土壤中，土壤聚集通常更大（平均增加24％）。总体而言，本研究的观察结果表明，DI改变了根系生长和土壤微生物群落结构，并有可能在本研究考虑的4年时间范围内影响SOC的储存和整个农业生态系统的功能。