Deficit Irrigation in Vitis labruscana Bailey ‘Concord’ in Central Washington

Abstract

<jats:p>Drought conditions in the western United States have limited water availability for the irrigation of agricultural products. This can have a dramatic impact on yield and quality of specialty perennial crops, such as juice grapes (<jats:italic>Vitis labruscana</jats:italic> Bailey). Washington State juice grape industry typically irrigates to 100% of crop-specific evapotranspiration (ET<jats:sub>c</jats:sub>) throughout the season to minimize yield loss. However, as conditions have limited water availability, growers need a new strategy to cope with the limited water supply. Regulated deficit irrigation (RDI) applies less water than plant ET<jats:sub>c</jats:sub> and has been shown to improve fruit quality in red wine grapes (<jats:italic>Vitis vinifera</jats:italic>). The objectives of this study were to evaluate the effects of RDI treatments on the yield and quality of ‘Concord’ juice grapes as compared with current commercial practice. The treatments reduced the amount of water applied between bloom and veraison by 25% (−25%), 33% (−33%), and 45% (−45%) from the control application. The results of this 4-year study initially indicated a dramatic decrease in yield in the −45% treatment (7.5 Mg/ha) as compared with the control treatment (19.2 Mg/ha); however, yield for the RDI treatments recovered in the subsequent seasons and was not statically different from the control. There were no statistical differences in fruit quality between treatments. This indicates that RDI has the potential to decrease water applied between bloom and veraison without impacting fruit quality; however, to avoid a sudden decrease in yield, it would be necessary to gradually reduce water applications over several years.</jats:p>

Optimizing Irrigation for Mechanized Concord Juice Grape Production

“…While differences in water supply accounted for some of the yield variation, climate variability clearly induced more variation in clusters per vine and berries per cluster from year to year. For example, the unusually light crop in 2012 mirrored that in another irrigation study in a nearby Concord vineyard (Stout et al 2017). The low cluster numbers in 2012 might have been caused by low bud fruitfulness due to reduced inflorescence initiation during the cool 2011 summer or by the early soil water deficit in 2011 (Vasconcelos et al 2009, Levin et al 2020).…”

“…In contrast, the 30% irrigation water savings achieved by irrigating at 50% ET c from fruit set through veraison (31% if the deficit continued through harvest) was associated with a Ψ s decrease below -1 MPa (indicating moderate water stress; Mirás-Avalos and Araujo 2021), a somewhat smaller and more open canopy, and a 14% reduction in yield below the control. In another study, conducted from 2011 through 2014 in a Concord vineyard in the same region, a comparable decrease in preveraison irrigation water supply reduced yield only in the second year (Stout et al 2017). However, irrigation generally improved yield after the first year when nonirrigated Concord vines were compared with irrigated vines in Arkansas over four years (Morris et al 1983) or in Ontario over five years (Reynolds et al 2005).…”

“…The large canopy of well-watered juice grapes uses substantially more water than does the smaller canopy of deficit-irrigated wine grapes (Dragoni et al 2006, Tarara and. However, contrary to the abundance of research into deficit irrigation of wine and table grapes (reviewed by Costa et al 2016, Permanhani et al 2016, Scholasch and Rienth 2019, Mirás-Avalos and Araujo 2021, little research has addressed the question of how limited water supply impacts fruit yield and composition of juice grapes (Morris et al 1983, Reynolds et al 2005, Stout et al 2017. A recent comprehensive review emphasized both the difficulty of generalizing optimal irrigation strategies across cultivars and regions, and the need for long-term studies (Mirás-Avalos and Araujo 2021).…”