Approach to Yield Response of Young Almond Trees to Deficit Irrigation and Biostimulant Applications

Saray Gutiérrez-Gordillo,Iván Francisco García-Tejero,Pedro Galindo,Víctor Hugo Durán Zuazo,María Del Carmen Arco,Amelia García-Escalera

doi:10.3390/horticulturae5020038

Saray Gutiérrez-Gordillo, Iván Francisco García-Tejero + Show 4 more

Open Access

https://doi.org/10.3390/horticulturae5020038

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Abstract

Water is the most limiting resource in many semi-arid areas of Mediterranean countries. Among the strategies to improve water productivity, the implementation of deficit irrigation (DI) strategies and the introduction of drought-tolerant crops in irrigated areas (such as almond) are being widely studied. Recently, the use of biostimulants to enhance crop tolerance to drought under water-scarcity scenarios is increasing. This work examines the response of three almond cultivars (‘Guara’, ‘Marta’, and ‘Lauranne’) in terms of yield and associated physiological responses in the main phenological stages to biostimulants (HYT® A and HYT® B plus) applied to young trees subjected to different irrigation levels: (i) a full irrigation treatment (FI), irrigated at 100% of crop evapotranspiration (ETC); and (ii) sustained-deficit irrigation (SDI75), irrigated at 75% of ETC. Significantly higher yields were obtained with HYT applications in 2 of 3 cultivars; these differences were most evident in the SDI75 treatment. In particular, ‘Guara’ registered the most significant improvements in nut yield when the HYT product was applied (15–20% higher). With regard to crop physiological responses, higher values of leaf water potential and stomatal conductance were noted with the HYT application in some cultivars and phenological stages. These results indicated that the use of biostimulants can be a feasible strategy for almond cultivation, especially when SDI is used.

Highlights

Almond (Prunus dulcis Mill.) represents the third largest crop in terms of surface area of cultivation in Spain and comprises 84% of the total European production (380,341 t in 2017)
Goldhamer and Girona [3] estimated that the water requirements of this crop for the climatic conditions of California, similar to those existing in southern Spain, oscillate between 9000 and 13,500 m3 ·ha−1, depending on the plant density, rootstock, crop management or pruning system, among other factors
This indicated that those trees that were treated with the biostimulant were less affected by drought conditions, and with a better hydration level than the untreated trees

Summary

Introduction

Almond (Prunus dulcis Mill.) represents the third largest crop in terms of surface area of cultivation in Spain and comprises 84% of the total European production (380,341 t in 2017). This performance represents only 5% of worldwide production, the USA being the largest international producer with 80% of the world market [1]. In Spain, almond production is relatively low because this crop has been grown in marginal areas where it is traditionally cultivated under limiting conditions, with production around 150 kg·ha−1. When almond is cultivated under optimum conditions and with maximum irrigation doses, higher production is achieved, in many cases up to 3000 kg·ha−1. Goldhamer and Girona [3] estimated that the water requirements of this crop for the climatic conditions of California, similar to those existing in southern Spain, oscillate between 9000 and 13,500 m3 ·ha−1 , depending on the plant density, rootstock, crop management or pruning system, among other factors

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