Deficit Irrigation in Vitis Labruscana Bailey 'Concord'
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HORTSCIENCE 52(3):450–456. 2017. doi: 10.21273/HORTSCI11450-16 vineyards that are irrigated use systems that do not lend themselves to RDI management Vitis labruscana (Moyer et al., 2013) and there is limited use Deficit Irrigation in of irrigation in ‘Concord’ vineyards in regions other than Washington State (Cuykendall Bailey ‘Concord’ in Central et al., 1999). The objective of this study was to eval- Washington uate RDI between bloom and veraison as a potential management strategy in ‘Con- Jason E. Stout and Joan R. Davenport1 cord’ production to reduce water use in Department of Crop and Soil Sciences, Irrigated Agricultural Research and response to drought conditions. Our study Extension Center, Washington State University, 24106 North Bunn Road, assessed the impact of three levels of RDI on yield, fruit quality, and seasonal soil moisture Prosser, WA 99350 distribution. R. Troy Peters Department of Biological Systems Engineering, Irrigated Agricultural Materials and Methods Research and Extension Center, Washington State University, 24106 North Plot design. This study was conducted in Bunn Road, Prosser, WA 99350 a 10 ha commercial ‘Concord’ vineyard lo- cated in the Yakima Valley American Viti- Additional index words. crop coefficient, shaded area, evapotranspiration culture Area (Sunnyside, WA) (46°20#21$N Abstract. Drought conditions in the western United States have limited water availability and 119°55#34$W) from Jan. 2011 to Feb. for the irrigation of agricultural products. This can have a dramatic impact on yield and 2015. The vineyard was planted in 1990 on quality of specialty perennial crops, such as juice grapes (Vitis labruscana Bailey). own-rooted vines with a 1.8 m · 3 m spacing Washington State juice grape industry typically irrigates to 100% of crop-specific and a north–northeast to south–southwest row orientation. Vines were trained on a sin- evapotranspiration (ETc) throughout the season to minimize yield loss. However, as conditions have limited water availability, growers need a new strategy to cope with the gle trunk to a wire 1.8 m above the soil surface. The canopy sprawled from the wire limited water supply. Regulated deficit irrigation (RDI) applies less water than plant ETc and has been shown to improve fruit quality in red wine grapes (Vitis vinifera). The and was minimally pruned. During the study, objectives of this study were to evaluate the effects of RDI treatments on the yield and all fertilizer and disease and pest manage- quality of ‘Concord’ juice grapes as compared with current commercial practice. The ment strategies were applied by the grower treatments reduced the amount of water applied between bloom and veraison by 25% based on commercial practices for high (L25%), 33% (L33%), and 45% (L45%) from the control application. The results of yields and applied as uniformly as possible this 4-year study initially indicated a dramatic decrease in yield in the L45% treatment across the vineyard (Hoheisel and Moyer, (7.5 Mg/ha) as compared with the control treatment (19.2 Mg/ha); however, yield for the 2016). RDI treatments recovered in the subsequent seasons and was not statically different from Plots were arranged in a randomized the control. There were no statistical differences in fruit quality between treatments. This block design with four blocks, each contain- indicates that RDI has the potential to decrease water applied between bloom and ing four treatments, for a total of 16 plots. veraison without impacting fruit quality; however, to avoid a sudden decrease in yield, it Each plot consisted of a 30-m section of three would be necessary to gradually reduce water applications over several years. rows. The two outside rows were buffer rows and the middle row served as the sample row, with samples and measurements taken from In Washington State, ‘Concord’ grape (V. during critical plant developmental stages, the center 10 vines. The vineyard was irri- labruscana) production is concentrated in the such as bloom and fruit set (Kriedemann and gated using drip emitters with a flow rate of Yakima Valley in Central Washington and Goodwin, 2003). 2.27 L·h–1 and a spacing of 0.9 m, resulting yield is heavily dependent on supplemental Previous research relating to ‘Concord’ in an application rate of 0.84 mm·h–1. Due irrigation because of the arid steppe climate irrigation strategies was largely conducted in to a lack of sufficient winter precipitation, (Fischer and Turner, 1978), which receives the eastern United States, which has high irrigation was applied before or immediately less than 250 mm of annual precipitation rainfall and a humid environment. Morris and following budbreak until the soil reached (Elsner et al., 2010, Fig. 1). Recently, low Cawthon (1982) and Morris et al. (1983a, field capacity ( 25% v/v) (Evans et al., winter snowfall has limited the availability of 1983b) have extensively studied the interac- 1993). Soil water content of the control surface irrigation supplies during the growing tion of irrigation, pruning severity, and fer- treatment was maintained throughout the season (April to October). In 2001, the Roza tilization on ‘Concord’ yield in Arkansas and growing season by the grower using standard irrigation district, which services the lower found that additional irrigation indirectly practices of applying about a 24-h irrigation set (20 mm of water) at weekly intervals. The Yakima Valley, only delivered 38% of nor- increased yield by increasing vine vigor. RDI treatments were initiated at 40% to 60% mal water delivery (Washington Department However, increased yields were inversely of Ecology, 2001). Similarly, in 2015, faced bloom, applied weekly, and ended at 40% to related to juice quality (Morris et al., 1983b). 60% veraison, with uniform irrigation to all with limited irrigation supplies, the members RDI is the technique of applying less plots thereafter. The treatments reduced the of the Roza irrigation district voted to shut off water than a plant would otherwise use irrigation availability for almost the entire water applied by 25% (–25%), 33% (–33%), during a specific period of the growing month of June to extend their allotment later and 45% (–45%) from the control applica- season. This technique can be used to cope into the growing season (Washington De- tion (Table 1) by reducing run time during partment of Ecology, 2015). Such decreases with limited irrigation availability or to im- irrigation. in available water can lead to large reduc- prove fruit quality in the case of red wine Initially, irrigation applications were tions in yield, especially when deficits occur grape (V. vinifera L.). However, there is little tracked by constant communication with the research on the impacts of RDI on ‘Concord’ grower. Starting in 2013, a pressure switch yield and berry quality in part because RDI (Model PS-1; Decagon Devices, Pullman, has the potential to limit yield and eco- WA) was installed in the drip tubing of the Received for publication 14 Oct. 2016. Accepted nomical ‘Concord’ production is largely control treatment and connected to a data for publication 3 Feb. 2017. focused on yield with a minimum set of logger (EM50; Decagon Devices) to monitor 1Corresponding author. E-mail: [email protected]. quality standards. In addition, many Concord the total time of each irrigation run. This was 450 HORTSCIENCE VOL. 52(3) MARCH 2017 used to calculate the total water applied based between the 10 sample vines in each plot (36 from June to October. However, in 2012, 2013, on the emitter flow rate. readings per treatment). The percent shaded and 2014 measurements were taken within Weather. Climate data were collected from area of the field was determined using the 24 h after the end of an irrigation event. The the Washington State University’s AgWeather- calculation method described by Battany total soil depth measured (140 cm) was divided Net system (http://weather.wsu.edu), Snipes (2006) and was subsequently used to calculate into two zones: the root zone (#60 cm) and ° # $ ° # weather station (46 17 56.4 ,–11954 the crop coefficient (Kc) using the correlation below the root zone (>60 cm) (Pradubsuk, $ 59.22 ) located less than 5 km from the equation of Kc to percent shaded area pre- 2008). The average volumetric water content research site. Total precipitation was measured, viously determined by Williams and Ayars (VWC) in each zone was determined from the and growing degree days (base of 10 °C, 1 Apr. (2005): VWC for each depth of surface (0–60 cm) and to 31 Oct.) and grass reference evapotranspi- subsurface (60–140 cm) for each neutron Kc ¼ðÞ0:017 · shaded percentage of field ration (ETo) were calculated. The accumulated probe site. Trends in the average VWC were growing degree days (GDD) increased season- À 0:008 evaluated by graphing the VWC by sampling ally: 1527 GDD accumulated in 2011, 1722 (1) date. GDD in 2012, 1835 GDD in 2013, and 1938 The fluctuation in soil water content was GDD in 2014. The long-term average accu- Soil moisture monitoring. The change further investigated by separating the data by in soil water content was monitored using depth. The average VWC for each treatment mulated GDD for the Snipes station was Ò 1749 GDD (2009–14); therefore, this trial a neutron probe (503 DR Hydroprobe ;CPN was graphed verses time for each 15-cm encompassed a cool season (2011), an aver- International, Inc., Concord, CA). Neutron depth each year. In addition, the average age season (2012), a warm season (2013), probe measurements were taken at 15-cm VWC at each depth was plotted vs. time for and a hot season (2014) as compared with increments to a depth of 90 cm in 2011, and each treatment and year to identify trends long-term averages. Precipitation during the 1400 cm in years 2012, 2013, and 2014 when based on treatment.