Water economy by Italia grapevines under different irrigation treatments in a Mediterranean climate

Abstract

<p style="text-align: justify;"><strong>Aims</strong>: A study was conducted to compare traditional vineyard irrigation (TI) using one drip emitter per vine, and partial root zone drying irrigation (PRD) using two drip emitters per vine (one per each vine side), at 2 rates of water application (controlled deficit (TI4 and PRD4) and non limiting (TI8 and PRD8)).</p><p style="text-align: justify;"><strong>Methods and results</strong>: Individual vine transpiration and vine water status were estimated from sap flow measurements by a stem heat balance method and midday stem water potential. The quality of the harvest was not significantly changed by the treatments. However, the vegetative growth was lower for the low irrigation rate treatments (TI4 and PRD4) and the PRD8 (compared to TI8). The total amount of water transpired by the vines during the season was estimated to 147 l/m2 without water limitation. A limiting water supply (TI4) lessened vine water use and improved the fraction of supplied water trapped by the vines (81 % for TI4 and 66 % for TI8). PRD decreased the transpiration of the vines, but also the efficiency of use of irrigation water.</p><p style="text-align: justify;"><strong>Significance and impact of study</strong>: Limited water supply saved water and improved the water capture efficiency by the roots of the vines. PRD irrigation saved water but the vine water capture efficiency was lower, limiting the practical interest of the method.</p>