Open Collections

Bevandick, Kirsten Irene

University of British Columbia

The timing and availability of water is changing for Okanagan cherry producers. Reducing irrigation after harvest by 25 % is a feasible method to conserve water in Okanagan cherry orchards; however, the effects of further reductions after harvest are unknown. To answer this question, the effects of postharvest deficit irrigation (PDI) in five Okanagan sweet cherry orchards (Prunus avium) at varying elevations and latitudes were assessed. Postharvest deficit irrigation was imposed, along with a full irrigation (FI) control, by reducing the amount of irrigation normally applied to trees after harvest by 25 %, and 50 %, in each of the five studied orchards. The aims of this study were to: (1) determine how PDI affects fruit yield, quality before and after storage; (2) assess the impacts of PDI on stem water potential, leaf gas exchange, water use efficiency (WUE), vegetative growth, and soil gas exchange; and (3) complete a cost benefit analysis (CBA) of adopting PDI in Okanagan cherry orchards. When all of the data were combined from five study sites, and two years, 50 % PDI had no effects on fruit quality, yield, stem water potential, leaf gas exchange, vegetative growth, or soil gas exchange. Growers may have irrigated above field capacity; therefore, reducing irrigation did not lead to increased water stress. Given PDI had no negative effects on fruit quality or yield, there were little to no costs associated with adopting PDI in Okanagan orchards. Adopting PDI resulted in an estimated net present value of $5.80 m⁻³ over 20 years. Although PDI did not generally induce water stress, trees that were water stressed had significant decreases in photosynthetic rates (An), stomatal conductance (gs), and transpiration rates (E), and significant increases in WUEintrinsic (An/gs). Stem water potential can likely drop to -1.88 MPa for a short period of time, or -1.32 MPa over the entire postharvest period without causing lasting damage to vascular tissues. This study offers important insight into the feasibility of adopting PDI in Okanagan cherry orchards. The CBA also provides one of the first assessments of the value of adopting water conservation practices in the Okanagan Valley.

Text

2022-10-11

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/82847

Biology

University of British Columbia

UBCO

http://creativecommons.org/licenses/by-nc-nd/4.0/