Scientists at the University of Minnesota are working with a global team to investigate the complex consequences of climate change on winter crops.
For some farmers, warmer winters may seem like a welcome shift because the difference in temperature may lessen freezing stress on plants and produce more perfect circumstances for producing overwinter cash crops and winter cover crops.
Researchers are discovering that when looking at climate change from a cross-seasonal viewpoint and accounting for decreased snowpack, the overall picture isn’t so bright. Reduced snowfall may expose winter crops to freezing temperatures, increasing the danger of agricultural dryness.
Zhenong Jin, Ph.D., an assistant professor in the Department of Bioproducts and Biosystems Engineering at the University of Minnesota, led an international team in researching the implications of warmer winters and declining snowpack using winter wheat (the largest winter crop in the United States) as an example in a new study published in Nature Climate Change.
“Although the implications of changes in snow for agricultural irrigation are beginning to be understood, the consequences of such for predominantly rainfed winter crops such as winter wheat remain largely unknown. There might be risks for being overoptimistic about growing overwinter crops under climate change,” said Jin.
The interannual variability of winter wheat output was attributed to various interaction environmental factors using panel regression, a strong statistical tool for analyzing repeated observations across time. These variables included freezing degree days during the cold season, growing degree days during the growing season, rainfall and snowfall during the growing season, and snow cover fraction during frozen days.
Our study highlighted the potential freezing risk in winters with decreased snow cover, especially when seedlings were exposed to comparatively warmer conditions that caused loss of winter-hardiness, which can cause significant yield losses of winter crops.
Peng Zhu
The researchers found:
- From 1999-2019, snow cover insulation weakened yield losses due to freezing stress by 22%.
- Projections show that future reduced snow cover could offset up to one-third of the yield benefit from reduced frost.
“Our study highlighted the potential freezing risk in winters with decreased snow cover, especially when seedlings were exposed to comparatively warmer conditions that caused loss of winter-hardiness, which can cause significant yield losses of winter crops,” said Peng Zhu, Ph.D., a Researcher from the Climate and Environment Sciences Laboratory of the Pierre Simon Laplace Institute, who co-led this study.
When producing climate-smart cultivars, this research will assist breeders in weighing the complicated tradeoffs between warming, decreasing snowpack, and occasional freezing hazards.
These findings also highlight the importance of enhancing the modeling of snow-related processes in crop models in order to better assess climate change effects and crop adaptation potential.
“It is worth noting that in some cropping systems freezing stress is appreciated, since it helps farmers control pests and diseases, and snow is even removed or at least made more compact by farmers to increase the freezing of the soil,” said Jin.
“When data becomes available, future studies might also need to account for the influence of snow on pests and diseases to comprehensively understand what future changes in snowpack mean for the cropping system.”
The USDA’s National Institute of Food and Agriculture (NIFA) and the French National Research Agency both contributed to this study’s funding.
Other members of the University of Minnesota research team include Taegon Kim and Chenxi Lin from Jin’s group and David Mulla from the Department of Soil, Water, and Climate.
