Modeling Transpiration and Canopy Conductance ofPeach (Prunus Persica) Trees under the Alternate PartialRoot Zone Drip Irrigation (APRDI)

摘要

We investigated canopy transpiration and canopy stomatal conductance of peachtrees under three irrigation patterns: fixed 1/2 partial root zone drip irrigation (FPRDI), alternate1/2 partial root zone drip irrigation (APRDI) and full root zone drip irrigation (FDI). Canopytranspiration was measured as transpiration rate per ground area using sap flux monitoredusing heat pulse sensors. Stomatal canopy conductance was calculated using Jarvis’s modeland inversion of Penman-Monteith equation. Results showed that transpiration rate andstomatal canopy conductance in FPRDI and APRDI were smaller than those in FDI. Moresignificantly, the total irrigation amount was greatly reduced, by 34.7% and 39.6% respectivelyfor APRDI and FPRDI in the PRDI treatment period. The daily transpiration was linearly relatedto the reference evapotranspiration but tree trunks of FDI carried more water than APRDI andFPRDI under the same evaporation demand, suggesting a restriction of transpiration water lossin the APRDI and FPRDI trees. By a comparison between the transpiration rates predicted byPenman-Monteith equation and the measured canopy transpiration rates for 60 days during theexperimental period, an excellent correlation along the 1:1 line was found for all the treatments(R2>0.80) and proved the reliability of the methodology.