Environmental characterization for rainfed maize production in the US Great Plains region

•Integrating NOAA weather and USDA crop data, provided an environtyping framework.•Ten environmental regions were identified in Kansas for rainfed maize production.•Extreme heat and water demand during maize critical period limit yields in Kansas.•Each 1 °Cd increase beyond 35 °C during the critical period reduced yields by 0.88 %. 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.