The impact of deficit irrigation strategies on sweet cherry (Prunus avium L) physiology and spectral reflectance
by Alejandro Jose Antunez Barria, Ph.D.
Washington State University
Co-Chairs: Claudio O. Stockle and Matthew D. Whiting
Prudent irrigation management of sweet cherry trees (Prunus avium L.)
requires periodic monitoring of plant water status to avoid physiological stress. In
recent years, on several fruit crops, various deficit irrigation techniques have
been shown to be effective for saving water resources and having little impact on
yield and quality. However, to date, little research has been conducted on sweet
cherry water management.
The purpose of this research was to investigate the physiological
response of sweet cherry to deficit irrigation strategies that varied in placement of
water. Additionally, correlations between sweet cherry canopy water status and
leaf spectral reflectance were investigated. Lastly, a weighing lysimeter system
was designed and utilized to accurately estimate transpiration of young potted
trees, in real time.
In the field, sweet cherry trees were subjected to three season-long
irrigation strategies: control (C) receiving 100% weekly replacement
evapotranspiration (ET), deficit irrigation (DI) receiving 50% replacement of ET to
the entire rootzone, and partial root-zone drying (PRD) receiving 50% ET to half
of the rootzone per irrigation. In general, there were subtle treatment effects on
leaf net photosynthetic rate (Pn), stomatal conductance (gs), leaf evaporation (E),
water use efficiency (WUE), chlorophyll fluorescence and assimilation response
parameters to carbon dioxide (CO2) and photosynthecic active radiation (PAR).
However soil water was conserved by PRD and DI vs. C by approximately 20%,
we found no clear physiological benefit to PRD.
Leaf spectral reflectance shows promise as a tool to estimate plant water
stress. Close correlations were found between reflectance and stem water
potential (?stem) in the visible range. The best correlation model predicting ?stem
used six wavelengths between 550 and 710 nm.
Throughout the 2004 growing seaon, transpiration from C trees was 846
mm m?2, and deficit-irrigated trees exhibited 31% to 35% less transpiration.
Stomatal conductance was reduced by irrigation treatments and correlated with
vapor pressure deficit and air temperature.
Overall, sweet cherries show tolerance to mild water stress and there is a
potential to adopt deficit irrigation strategies in commercial production systems.
School:Washington State University
School Location:USA - Washington
Source Type:Master's Thesis
Keywords:sweet cherry deficit irrigation
Date of Publication: