Abstract:
The relationship between precipitation and evapotranspiration (ET) is critical to
understanding water cycle related dynamics in ecosystems, including crops.
Existing studies of bioenergy crops have primarily focused on annual or
seasonal ET rates, with less attention given to the immediate ET response
following precipitation events. This study examines the variation in ET rates in
the days subsequent to precipitation events across various bioenergy
crops—corn, switchgrass, and prairies—utilizing 13 years (2010–2022) of
growing season data. Meteorological and eddy covariance flux data were
collected from seven eddy covariance flux towers as part of the GLBRC scaleup experiment at the Kellogg Biological Station Long Term Ecological Research
sites. The analysis revealed that average ET peaked the day after precipitation and
declined linearly over the following days, with a statistically significant relationship
(p-value = 0.00027, R2 = 0.96). Neither the type of biofuel vegetation nor the
historical land use significantly influenced ET post-precipitation events
(p-values = 0.53 and 0.153, respectively). Key predictors of ET following
precipitation events include shortwave radiation, season, day of the year,
ambient temperature, vapor pressure deficit (VPD), long-wave radiation,
precipitation amount, soil moisture, and annual variability. These findings
enhance our comprehension of ET responses in bioenergy crop systems, with
implications for water management in sustainable agriculture.
