Evaluating soil evaporation and transpiration responses to alternate partial rootzone drying to minimise water losses

Abstract Purpose Partial rootzone drying (PRD) typically alternates the dry and irrigated parts of rootzone, but how plant physiology soil evaporation respond to this alternation are poorly understood. Methods Dwarf tomatoes were grown in small split pots comprising two 250 cm 3 compartments fully (WW: 100% ET c ) or subjected three deficit irrigation treatments (75% ): homogeneous (HRD; evenly distributed); fixed PRD (PRD-F, applied one compartment); alternated (PRD-A: as PRD-F alternating compartment every days). Stem diameter evapotranspiration monitored during cycles. The day after side root system, whole-plant gas exchange leaf water potential measured following step increments vapour pressure deficit. Results Alternation did not affect stem contractions evapotranspiration, which lower HRD than treatments. However, was higher PRD-A PRD-F. Following alternation, counteracted by decreased transpiration compared with PRD, despite similar overall content. VPD change pattern. Conclusion Irrigation placement determined moisture distribution, turn affected whole exchange. Optimising frequency maximise savings while ensuring productive use needs consider distribution affects both use.