Deficit Irrigation as a Suitable Strategy to Enhance the Nutritional Composition of HydroSOS Almonds

Abstract

The Mediterranean region is one of the most water-scarce areas worldwide and is considered a climate-change hotspot. To assure the viability and competitiveness of irrigated agriculture, it is vital to implement strategies that can maximize water saving without compromising yield. Deficit irrigation (DI) for cultivating drought-tolerant species such as almond (Prunus dulcis (Mill.) D.A. Webb) can help in achieving this goal, while at the same time improving fruit chemical composition. This work evaluated the effect of DI techniques and cultivars on the chemical composition of almonds (cvs. Marta, Guara, and Lauranne) in order to elucidate the most suitable irrigation dose under water-scarcity scenarios. Three irrigation regimes were imposed: a control treatment (FI), which was fully irrigated, receiving 100% of the irrigation requirement (IR), and two sustained-deficit irrigation (SDI) strategies that received 75% (SDI75) and 65% (SDI65) of IR. Significant differences among cultivars and irrigation treatments were observed for antioxidant activity and organic acid, sugar, and fatty acid content, which were increased by the SDI strategies. In addition, highly significant correlations were found between leaf-water potential and components such as fumaric acid, sugars, and fatty acids. In terms of the cultivars, cv. Marta showed the highest antioxidant activity, cv. Guara was the richest in organic acids, and cv. Lauranne had the highest fatty acid content. Consequently, SDI strategies improved almond quality parameters related to their nutritional and sensory composition, with significant water savings (reductions of 25–35%) and without important yield loss.

How does water stress and roasting temperature affect the physicochemical parameters of almonds?

“…The main organic acids found were citric, tartaric, malic and isobutyric. All these OA had been previously found in raw almonds except for isobutyric acid (Egea et al, 2009;Lipan et al, 2020). Citric acid was higher in T2 (2.5 g kg -1 ) than T1 (2.3 g kg -1 ) and the contrary was observed for the isobutyric acid and total organic acids content (∑OA).…”

“…Similar results were reported in previous studies in which an increase in all OA, was observed in almonds cvs. Marta, Guara, and Lauranne grown both under RDI or sustained deficit irrigation (SDI) (Lipan et al, 2020;Gutiérrez-Gordillo et al, 2020). Regarding the roasting process, citric, isobutyric and ∑OA increased 1.18-fold, 2.58-fold, (from 150 to 190 ºC) and 1.03-fold (from 150 ºC to 190 ºC) respectively, with the roasting temperature.…”

Water Management in Woody Crops: Challenges and Opportunities

“…They observed significant differences in the response of these cultivars, detecting an increase in the contents of sugars and fatty acids in the almonds from the SDI treatments, without relevant yield losses. These authors found highly significant correlations between leaf water potential (an indicator of tree water status) and fumaric acid, sugars, and fatty acids in the almonds [5]. This work opens the way to defining irrigation protocols adapted to specific almond cultivars and that account for both production and the nutritional composition of almonds.…”

“…The efficient use of deficit irrigation strategies is the subject of two articles within this Special Issue. First, Gutiérrez-Gordillo et al [5] tested two sustained deficit irrigation (SDI) regimes, varying the dose of water applied, against a full irrigation control in three almond cultivars grown in South Spain. They observed significant differences in the response of these cultivars, detecting an increase in the contents of sugars and fatty acids in the almonds from the SDI treatments, without relevant yield losses.…”

Crop Diversification and Resilience of Drought-Resistant Species in Semi-arid Areas: An Economic and Environmental Analysis

“…• In almond orchards, regulated deficit irrigation strategies and subsurface drip irrigation have allowed a 45% water saving while production was reduced by 17% [45]; deficit irrigation has improved almond quality and water saving, without significant yield loss [46]. A crucial requirement to perform LCA and LCC is the availability of complete and accurate technical and economic data-set regarding the whole cultural cycle.…”