Impact of the Covering Material on Drought Tolerance Responses and Soil Water Content in Two Cultivars of Young Blueberry Plants under Protected Cultivation

Abstract

There is a lack of information on how protected cultivation alters plant and soil responses to water stress. The objective of this study was to understand the influence of the covering material on drought tolerance responses and soil water content in the effective rooting zone in two promising new cultivars grown under contrasting climatic conditions. (2) Methods: Two experiments were conducted in young blueberry (Vaccinium corymbosum L.) orchards, cv. Blue Ribbon and cv. Top Shelf, in two different locations in the south-central region of Chile (Linares and Traiguén) in 2018–2019 and 2019–2020. Four treatments (uncovered control, net, woven, and plastic) were installed from bud break to leaf senescence. (3) Results: Woven and plastic-covered plants showed no relationship between stem water potential and stomatal conductance, while uncovered and net-covered plants showed a quadratic relationship between both variables. Under deficit irrigation, higher plant water status, stomatal conductance, and photosystem II efficiency were found in covered plants. ‘Top Shelf’ showed greater tolerance to water stress than ‘Blue Ribbon’ due to more sensitive stomatal control. (4) Conclusions: Protected cultivation delayed the onset of water stress, maintained high stomatal conductance, and reduced photoinhibition in young blueberry plants.