Preliminary Evaluation of the Application of Algae-Based Biostimulants on Almond

To improve almond performance under water limitations, the use of algae-based biostimulants may become a useful tool to reduce drought stress. However, besides possible effects on plant behavior, changes in fruit characteristics must also be considered. In this work, a preliminary study on the effect of two levels of an Ascophyllum nodosum-based biostimulant in the chemical characteristics of fruits from rain-fed cv. Marinada almond trees was carried out. The use of the recommended manufacturer's dosage resulted in a decreased content of soluble sugars and proteins when compared to the use of half the recommended dosage and the control assays (water only). Similarly, and although no significant differences were recorded, the content of bioactive compounds (ortho-diphenols, total phenolics, and flavonoids) tended to increase in non-treated trees. Finally, sensory analysis of treated and non-treated fruits did not record any changes in the perceived attributes, showing that no negative effects on consumers' acceptance will be caused by the application of this product. Long-term studies are needed to further confirm these results, also aimed at the monitoring of leaf gas exchange and water status parameters of trees.