Identifying regions with similar productivity and yield-limiting climatic factors enables the design of tailored strategies for rainfed maize (Zea mays L.) production in vulnerable environments. Within the United States (US), the Great Plains region is susceptible to weather fluctuations, particularly in Kansas, where rainfed maize production is a significant agricultural activity. This study aims to delimit environmental regions with similar crop growth conditions and to identify the main climatic factors limiting rainfed maize yield, using the state of Kansas as a case study. For this purpose, databases encompassing the period from 1993 to 2021 period, including NOAA weather station data (n = 208), USDA county maize yield data, and crop phenology reports at the agricultural district scale, were compiled for analysis. Four periods based on crop phenology data were defined: fallow period, vegetative period, critical period around flowering (± 15 days), and grain filling period, each with reported climatic variables. A Fuzzy c-means clustering algorithm identified ten productive regions. Grain yields range from ∼3500 to ∼7500 kg ha−1, spanning South-West to North-East regions. Within each region, correlation analysis was carried out between detrended yields and climatic anomalies to identify the most relevant seasonal climatic factors over 29 years. Extreme degree days (i.e., accumulating maximum air temperature above 35 °C) and vapor pressure deficit during the critical period are the main climatic drivers of rainfed maize yield across regions. In Kansas, extreme degree days exhibit a east-to-west and north-to-south increase. Yield decreased by 46 kg ha−1 per °Cd of extreme degree days during the critical period across regions, with maximum yield penalty in the south-east region. This methodology contributes to the knowledge of the most relevant climatic drivers of rainfed maize, with the potential for application in other regions for the development of adaptive management strategies and policies.

中文翻译：

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美国大平原地区雨养玉米生产的环境特征


确定具有相似生产力和产量限制气候因素的地区，可以为脆弱环境中的雨养玉米 （Zea mays L.） 生产设计量身定制的策略。在美国 （US） 境内，大平原地区容易受到天气波动的影响，尤其是在堪萨斯州，雨养玉米生产是一项重要的农业活动。本研究旨在以堪萨斯州为例，划定具有相似作物生长条件的环境区域，并确定限制雨养玉米产量的主要气候因素。为此，编制了涵盖 1993 年至 2021 年期间的数据库，包括 NOAA 气象站数据 （n = 208）、美国农业部县玉米产量数据和农业区规模的作物物候报告，以供分析。根据作物物候数据定义了四个时期：休耕期、营养期、开花前后的关键期（± 15 天）和籽粒灌浆期，每个时期都有报告的气候变量。模糊 c-means 聚类算法确定了 10 个生产区域。粮食产量从 ∼3500 到 ∼7500 公斤公顷-1 不等，横跨西南到东北地区。在每个区域内，对去趋势化的产量和气候异常进行了相关性分析，以确定 29 年中最相关的季节性气候因素。极端气温天数（即最高气温累积超过 35 °C）和关键时期的蒸气压不足是各地区雨养玉米产量的主要气候驱动因素。在堪萨斯州，极端气温日呈从东到西和从北到南的增加。 在各地区的关键时期，极端度日的产量每°Cd 减少了 46 kg ha-1，东南部地区的产量损失最大。该方法有助于了解雨养玉米最相关的气候驱动因素，并有可能应用于其他地区制定适应性管理战略和政策。