The challenge of chilling injury amid shifting maize planting boundaries: A case study of Northeast China

Abstract

CONTEXT

With the northward shift of planting belts and increased temperature variability under climate change, chilling injury to crops migrating northward may remain dangerous and worsened by the expansion intensity.

OBJECTIVE

We examined the similarities between adjustments in maize planting and migration systems to identify cold maladaptation using climate and maize planting data from 1981 to 2020.

METHODS

First, the boundaries of maize planting areas were identified based on the critical accumulated temperature thresholds for different varieties, and the range of planting changes was quantified. Next, using the Theil-Sen median and Center of gravity migration model, the trend of maize expansion northward and eastward in Northeast China was revealed. Finally, the chilling injury risk of maize migration in sensitive and non-sensitive growing areas was evaluated for different periods and situations based on the natural disaster formation theory.

RESULTS AND CONCLUSIONS

Maize distribution reacted positively to the Planting system boundary trend with northward movement and eastward expansion. The migration distance and planting rate in sensitive areas were more obvious than in non-sensitive areas, whereas the positive northward adaptation put maize under unfavorable cold conditions, particularly during slowing warming periods. Following the edge of maize migrating to cooler or higher elevation areas, danger of chilling injury has considerably elevated. Overall, compared to non-sensitive areas, newly added maize in sensitive areas exhibited higher vulnerability and hazard levels, alongside lower yields and limited capacity for mitigation. Local farmers have insufficient technical facilities or knowledge of the necessary management after relocation. Using a Multi-Model Ensemble regional climate scenarios, we calculate that High-latitude locations will continue to provide harsh environments for maize, which is susceptible to freezing, even though cropping system boundaries will continue to shift northward, which may present new planting opportunities for maize.

SIGNIFICANCE

Cold adaptation remains crucial when crops move northward to mitigate heat and heat damage caused by global warming.