Groundwater plays a key role in regulating the transition from meteorological droughts (MD) to agricultural droughts (AD), though its specific influence during crop growth remains unclear. In this study, daily effective root zone soil moisture and annual yield for winter wheat and summer maize were simulated using Aquacrop model under four scenarios: Scenario 1 (groundwater level at 1 m depth), Scenario 2 (groundwater level at 2 m depth), Scenario 3 (groundwater level at 3 m depth), and Scenario 4 (groundwater level at 4 m depth). Based on the simulated data, the propagation probabilities, propagation times (PT), translation rates of drought events, and changes in drought characteristics under the four scenarios were calculated, revealing the specific impact of groundwater levels on the propagation from MD to AD. The results indicated that (1) the probability of drought propagation increased with either a decrease in the groundwater level or an increase in the MD severity. Notably, a decrease in groundwater level from 1 m to 2 m depth results in a substantial rise in propagation probability, with an average increase of 114.0 % and 118.9 % for winter wheat and summer maize, respectively. (2) PT was shortened by 2–4 days for each 1 m drop in the groundwater level. When the severity of MD intensified from severe to extreme, the PT was shortened by an average of 8 days and 10 days during the phenological stages of summer maize and winter wheat, respectively. Both crops exhibited shorter PTs during the emergence, grouting, and maturity stages, and longer PTs during the tillering and heading stages. (3) Overall, the decline of groundwater levels accelerates the translation rate of drought events. In addition, longer and stronger drought characteristics were observed especially at low levels of groundwater. (4) The optimal groundwater level was found to be about 1 m and 2 m for winter wheat and summer maize in the Huaibei Plain, respectively. These findings provide valuable insights for enhancing drought resilience and optimizing irrigation and groundwater management in the Huaibei Plain.

中文翻译：

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地下水对农作物生育期气象干旱向农业干旱传播的影响——以淮北平原为例


地下水在调节从气象干旱 （MD） 到农业干旱 （AD） 的过渡中起着关键作用，尽管其对作物生长的具体影响尚不清楚。本研究使用 Aquacrop 模型模拟了冬小麦和夏玉米的日有效根区土壤水分和年产量，分为情景 1（1 m 深处的地下水位）、情景 2（2 m 深处的地下水位）、情景 3（3 m 深处的地下水位）和情景 4（4 m 深处的地下水位）。基于模拟数据，计算了 4 种情景下的传播概率、传播时间 （PT）、干旱事件的转换速率和干旱特征的变化，揭示了地下水位对 MD 到 AD 传播的具体影响。结果表明：（1） 干旱传播的可能性随着地下水位的降低或 MD 严重程度的增加而增加。值得注意的是，地下水位从 1 m 深度降低到 2 m 深度导致传播概率大幅增加，冬小麦和夏玉米的平均增加率分别为 114.0% 和 118.9%。（2） 地下水位每下降 2 米，PT 就会缩短 4-1 天。当 MD 严重程度由重度加剧为极度时，夏玉米和冬小麦物候期 PT 分别平均缩短 8 d 和 10 d。两种作物在出苗、灌浆和成熟阶段都表现出较短的 PTs，而在分蘖和抽穗阶段表现出较长的 PTs。（3） 总体而言，地下水位下降加快了干旱事件的转化速度。 此外，观察到更长和更强的干旱特征，尤其是在低水平地下水的情况下。（4）淮北平原冬小麦和夏玉米的最佳地下水位分别为 1 m 和 2 m 左右。这些发现为增强淮北平原的抗旱能力、优化灌溉和地下水管理提供了有价值的见解。