TITLE:
Observations of Spring Hard Freeze Injury to C4 Perennial Grasses Native to the Great Plains, USA
AUTHORS:
Rob Mitchell, Daren Redfearn
KEYWORDS:
C4 Perennial Grasses, Spring Hard Freeze
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.10 No.5,
May
20,
2019
ABSTRACT: The native prairies of the Great Plains USA are
dominated by perennial C4 grasses like switchgrass (Panicum virgatum) and big bluestem (Andropogon gerardii). Spring hard freeze
injury to C4 perennial grasses is rare but information is lacking in
the literature. Our objective was to document effects of spring hard freeze
damage to C4 perennial grasses native to the Great Plains USA. On 2
May at 24:00 pm, air
temperature near Mead, Nebraska was below freezing and remained below freezing
until 8:00 am on 3
May, with a minimum air temperature of -2.8°C. Based on 50-year of weather data
for this site, a minimum threshold temperature of 0°C on or after 3 May
occurred 16 times, but a minimum threshold temperature of -2.8°C on or after 3
May occurred only twice. Grass tillers were visually evaluated to determine
extent of freeze damage. The terminal 3- to 5-cm of the leaf lamina was blackened 4-d after
freezing and had complete browning, rolling, and desiccation 14-d after
freezing. Tiller survival was not negatively affected by the freezing
temperatures in May 2004. As the growing season progressed, all agronomic and
livestock responses were within normal ranges for these C4 grasses.
This is the first field report of multiple C4 prairie grass species
responses to a spring hard freeze following significant spring growth. Plant
recovery to this late-spring hard freeze demonstrates the ecological resilience
of these C4 prairie grasses. These rare spring hard freezes had
short-term impacts on C4 grasses but did not negatively impact
agronomic performance for forage or bioenergy later in the growing season.