Assessment of sustainable deficit irrigation in a Moroccan apple orchard as a climate change adaptation strategy

• Published in: The Science of the total environment Vol. 642; pp. 574 - 581
• Main Authors: El Jaouhari, Nabil, Abouabdillah, Aziz, Bouabid, Rachid, Bourioug, Mohamed, Aleya, Lotfi, Chaoui, Mohamed
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.11.2018; Elsevier
• Subjects: Crop evapotranspiration; Ecophysiological responses; Environmental Sciences; Fruit quality; Malus domestica (var. Gala); Reference evapotranspiration; Sustainable deficit irrigation ‘SDI’; Reference evapotranspiration; Ecophysiological responses; Crop evapotranspiration; Fruit quality; Malus domestica (var. Gala); Sustainable deficit irrigation ‘SDI’
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2018.06.108

This study was conducted over three consecutive years, 2015, 2016 and 2017, in the Imouzzer Kander region located in northwestern Morocco. The main objective is to evaluate apple tree responses to two sustainable deficit irrigation strategies with 75% (T2) and 50% (T3) of calculated crop evapotranspiration (ETc), compared to a control irrigated with 100% ETc (T1). During the three experiment years, estimated reference evapotranspiration (ET0) was 630, 684 and 728 mm, respectively, in 2015, 2016 and 2017. Under the two restricted regimes, shoot length and fruit size evolution were not significantly affected. During the fruit set of 2017, no significant effects of sustainable deficit irrigation on the relative water content were observed, whereas they increased significantly during the fruit-swelling stage for the T3 treatment. Likewise, net CO2 assimilation (An) was not affected by the irrigation dose, whereas it increased significantly and inversely proportional to the amount of applied water during fruit swelling. Thus, under our experimental conditions, the trees subjected to extreme deficit irrigation (T3) were not stressed at either stage. Moreover, deficit irrigation at 75% ETc increased apple yield significantly. In contrast, deficit irrigation at 50% ETc throughout the cycle was not enough to maintain an acceptable fruit size for the three studied campaigns. However, the best qualitative performance, notably for fruit firmness and sugar content, was attributed to this irrigation regime (T3). [Display omitted] •Mediterranean region is considered a “hot spot” for climate change.•In many regions of Morocco, farmers overestimate plant water requirements.•Smart irrigation for apple trees requires determination of a correct Kc.•SDI of apple trees with 75% ETc shows an increase in crop yield.•Fruit firmness increased with 50% of reduction of the applied water