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Please cite this article in press as: Galindo, A., et al., Deficit irrigation and emerging fruit crops as a strategy to save water in Mediterranean semiarid agrosystems. Agric. Water Manage. (2017) b s t r a c tWater scarcity in Mediterranean climate areas will be progressively aggravated by climate change, population increase and urban, tourism and industrial activities. To protect water resources and their integrity for future use and to improve biodiversity, besides following advanced deficit irrigation strategies in fruit cultivation, attention could well be directed towards what are at present underused plant materials able to withstand deficit irrigation with minimum impact on yield and fruit quality. To this end, the state of the art as regards deficit irrigation strategies and the response of some very interesting emerging fruit crops [jujube (Zizyphus jujuba Mill.), loquat (Eriobotrya japonica Lindl.), pistachio (Pistacia vera L.) and pomegranate (Punica granatum L.)] are reviewed. The strengths and weaknesses of deficit irrigation strategies and the mechanisms developed by these emerging fruit crops in the face of water stress are discussed. The response of these crops to deficit irrigation, with special attention paid to the effect on yield but also on fruit quality and health-related chemical compounds, was analysed in order to assess their suitability for saving water in Mediterranean semiarid agrosystems and to analyze their potential role as alternatives to currently cultivated fruit crops with higher water requirements. Finally, the factors involved in establishing an identity brand (hydroSOS) to protect fruits obtained under specific DI conditions are discussed.

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PreprintRegulated deficit irrigation (RDI) results are affected by the actual water stress level reached during the treatments. The irrigation scheduling based on water status measurements, such as trunk diameter fluctuations, can control in an accurate way the water restrictions. However, the number of works that use these indicators as isolate parameter to control the schedule is scarce in general, and very scarce in olive trees. Building on previous works, the aim of this article is to schedule an RDI strategy in olive trees based on threshold values of maximum daily shrinkage (MDS) and trunk growth rate (TGR) without reference trees. The experiment was performed in a 40 years-old table olive orchard (cv Manzanillo) in Seville (Spain) for 3 years (seasons from 2011 to 2013). Three different irrigation treatments were considered in a completely randomized block design. Control trees were over-irrigated (125% crop evapotranspiration, ETc) in order to obtain fully irrigated conditions. Water stress conditions were applied during Phase II (pit hardening) in the RDI-2 treatment or during Phase II and Phase I (full bloom) in RDI-12. In both RDIs, a treatment recovery (Phase III) was performed before harvest. The trunk diameter fluctuation indicator was selected according to the phenological stage. TGR was used in conditions of full irrigation or moderate water stress level, such as Phase I and Phase III. TGR threshold values based on previous works were selected: 20 mday−1, RDI-2; 10 mday−1, RDI-12 (Phase I) and −5 mday−1, both treatments, Phase III. Only in one season RDI-2 was scheduled with TGR values (−10 mday−1) during Phase II. MDS threshold values were determined as the ratio between measured MDS and fully irrigated MDS (the so called MDS signal). The latter was estimated from a baseline. During Phase II, RDI-2 was irrigated with a threshold value of 0.9, while RDI-12 was irrigated with a threshold value of 0.75. MDS signal was not useful for most of the period considered and it did not agree well with fruit drop or fruit size. Conversely, the average of TGR during Phase II was significantly linked to fruit drop and fruit size, and so were the midday stem water potential and stress integral. Recommendations about the management of TGR are discussed. The water stress level in the experiments was moderate and no significant differences in yield were found. However, the trend of yield reduction in RDI-12 was likely related with a fruit drop and a reduction in crown volume. The yield quality did not decrease in the RDIs treatments, on the contrary, pulp:stone ratio improved significantly in some of the seasons