Earlier planting fails to replicate historical production conditions for US spring wheat under future climates

Authors: SAVALKAR, SUPRIYA - Washington State University; PUMPHREY, MICHAEL - Washington State University; Garland Campbell, Kimberly; SCARPARE, FABIO - Washington State University; FERDOUSI, TANVIR - University Of Virginia; SWARUP, SAMARTH - University Of Virginia; STOCKLE, CLAUDIO - Washington State University; RAJAGOPALAN, KIRTI - Washington State University

Submitted to: Communications Earth & Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/19/2025
Publication Date: 8/27/2025
Citation: Savalkar, S., Pumphrey, M.O., Garland Campbell, K.A., Scarpare, F.V., Ferdousi, T., Swarup, S., Stockle, C.O., Rajagopalan, K. 2025. Earlier planting fails to replicate historical production conditions for US spring wheat under future climates. Communications Earth & Environment. 2025(6). Article 708. https://doi.org/10.1038/s43247-025-02716-0.
DOI: https://doi.org/10.1038/s43247-025-02716-0

Interpretive Summary: Global warming and changing climate are affecting crop growth and development. In order to continue to produce adequeate amounts of food, some cropping system practices will need to change. Planting earlier in the season to take advantage of warmer spring temperatures is one of these recommended changes. However, earlier planting does not work in all environments. This research was done in order to predict which spring wheat growing environments in the U.S. would benefit from earlier planting and also to predict which other cropping system or changes to the crop itself will be useful in the coming years. The results of this research are useful to agronomics, farmers and plant breeders as they strive to maintain and increase future grain food output.

Technical Abstract: Global warming can increase crop heat stress exposure, adversely affecting crop yields and quality. Earlier planting is widely considered in climate change literature as a potential adaptation strategy by shifting the growing season to cooler periods. However, the effectiveness of earlier planting in achieving overall temperature exposures during the crop growth season that are at least as favorable as historical conditions remains unclear. Our objective is to comprehensively assess the potential effectiveness of earlier planting as an adaptation strategy by addressing two key questions: How effective is earlier planting in reducing exposure to excessively high temperatures across different growth stages? What are the associated trade-offs in temperature exposure, and can historical conditions be matched with this adaptation strategy? We focus on major US spring wheat growing states as a case study, analyzing lethal, critical, suboptimal, and optimal temperature thresholds by growth stage to quantify the impact of earlier planting. Our findings indicate that while earlier planting does reduce exposure to critical and lethal high-temperature categories during some reproductive stages, it generally fails to replicate historical production conditions for the majority of the US spring wheat production regions (contributing 85% of the current production). This trend persists across various future time frames and emission scenarios. The Pacific Northwest US presents an exception; however, even in this region, certain early and late growth stages may experience worse-than-historical conditions requiring management. The planting window with historically-equivalent temperature exposures also narrows from 11 weeks to 1-7 weeks, presenting additional logistical challenges. Given that the Pacific Northwest US accounts for less than 15% of the national spring wheat production, at a national scale, current production levels are unlikely to be sustained solely by relying on earlier planting as an adaptation strategy. This is a critical consideration, especially given that many climate change assessments frequently promote earlier planting as an effective adaptation strategy without fully exploring its trade-offs and focusing primarily on reducing heat stress in a few critical growth stages. Exploring additional adaptation strategies to maintain current national production levels is important.