Critical benefits of snowpack for winter wheat are diminishing

Date:
April 11, 2022
Source:
University of Minnesota
Summary:
Scientists are studying the complex effects of climate change
on winter crops. Warming winters may sound like a welcome change
for some farmers because the change in temperature could reduce
freezing stress on plants and create more ideal conditions for
growing overwinter cash crops and winter cover crops. However,
when looking at climate change from a cross- seasonal perspective
and accounting for declining snowpack, researchers are finding
that the whole picture isn't so sunny.



FULL STORY ========================================================================== University of Minnesota scientists are partnering with a global team to
study the complex effects of climate change on winter crops.


========================================================================== Warming winters may sound like a welcome change for some farmers because
the change in temperature could reduce freezing stress on plants and
create more ideal conditions for growing overwinter cash crops and winter
cover crops.

However, when looking at climate change from a cross-seasonal perspective
and accounting for declining snowpack, researchers are finding that the
whole picture isn't so sunny.

Reduced snow may result in more exposure of winter crops to freeze and
could mean greater risks for agricultural drought.

In a new study published in Nature Climate Change, 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 that could be associated with warmer
winters and declining snowpack, using winter wheat (the largest winter
crop in the U.S.) as an example.

"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.

Researchers used panel regression, a powerful statistical method to
analyze repeated observations over time, to attribute the interannual variability of winter wheat yield to multiple interactive environmental factors. These factors included cold season freezing degree days,
growing degree days, rainfall and snowfall during the growing season
and snow cover fraction during frozen days.



==========================================================================
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.

This research will help inform breeders as they consider the complex
tradeoffs among warming, reduced snowpack and occasional freezing threats
when developing climate-smart cultivars.

These results also highlight the necessity of improving the representation
of snow associated processes in crop models to better evaluate climate
change effects and adaptation potential in cropping systems.

"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." Funding for this research was partially supported by the USDA National Institute of Food and Agriculture (NIFA)
and the French National Research Agency.

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.


========================================================================== Story Source: Materials provided by University_of_Minnesota. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Peng Zhu, Taegon Kim, Zhenong Jin, Chenxi Lin, Xuhui Wang, Philippe
Ciais, Nathaniel D. Mueller, Amir Aghakouchak, Jianxi Huang, David
Mulla, David Makowski. The critical benefits of snowpack insulation
and snowmelt for winter wheat productivity. Nature Climate Change,
2022; DOI: 10.1038/ s41558-022-01327-3 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/04/220411184246.htm

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