Whole-canopy gas exchange chambers to accurately estimate canopy water use of 'Tempranillo' grapevines (Vitis vinifera L) under various irrigation regimes in a semi-arid climate

摘要

An accurate estimation of grapevine water use is vital for efficient irrigation water management in vineyards, particularly in regions dependent on the availability of freshwater, and in light of increasing freshwater scarcities in arid and semi-aridregions globally. Using custom-built whole-canopy chambers coupled to a portable infrared gas analyser, we estimated the daily water requirements of mature grapevines [Vitis vinifera L. 'Tempranillo') in the field under high environmental demand (vapourpressure deficit) and several irrigation regimes (full irrigation at 100% of crop evapotranspiration or ETC; regulated deficit irrigation and sustained deficit irrigation ranging between 30-50% of ET,). Environmental conditions, soil moisture, and vine water status (midday stem water potential) were measured simultaneously. Our results indicate that mature fully-irrigated grapevines in the field use over 35 L of water vine1 d1 during the peak of the summer. In the same vines, night transpiration represented up to 12% of the total daily water use. Canopy water use efficiency (WUE) was highest early in the morning perhaps due to the relatively higher proportion of diffuse light at that time and, consequently, lower transpiration rates. Daily water use was lower in the reduced irrigation treatments and with negligible nocturnal water loss. Whole-canopy gas exchange chambers built for and used in this study have proven to be a valuable tool for the quantification of plant water use and therefore irrigation scheduling in vineyards.