Modeling Transpiration and Canopy Conductance of Peach (Prunus Persica) Trees under the Alternate Partial Root Zone Drip Irrigation (APRDI)

摘要

We investigated canopy transpiration and canopy stomatal conductance of peach trees under three irrigation patterns: fixed 1/2 partial root zone drip irrigation (FPRDI), alternate 1/2 partial root zone drip irrigation (APRDI) and full root zone drip irrigation (FDI). Canopy transpiration was measured as transpiration rate per ground area using sap flux monitored using heat pulse sensors. Stomatal canopy conductance was calculated using Jarvis's model and inversion of Penman-Monteith equation. Results showed that transpiration rate and stomatal canopy conductance in FPRDI and APRDI were smaller than those in FDI. More significantly, the total irrigation amount was greatly reduced, by 34.7% and 39.6% respectively for APRDI and FPRDI in the PRDI treatment period. The daily transpiration was linearly related to the reference evapotranspiration but tree trunks of FDI carried more water than APRDI and FPRDI under the same evaporation demand, suggesting a restriction of transpiration water loss in the APRDI and FPRDI trees. By a comparison between the transpiration rates predicted by Penman-Monteith equation and the measured canopy transpiration rates for 60 days during the experimental period, an excellent correlation along the 1:1 line was found for all the treatments (R{sup}2>0.80) and proved the reliability of the methodology.