Fertilization with Seaweed (Laminaria japonica) on the characteristics of the bunch and the quality of the grape must of ‘Cabernet Sauvignon’

The objective of the present work was to study the influence of the foliar application of seaweed (Laminaria japonica), on the bunch and on the must in the 'Cabernet Sauvignon' grape. The experiment was carried out in the years 2021/2022, in a 21-year-old commercial vineyard, in the municipality of "Dom Pedrito" – "Rio Grande do Sul" (RS). A completely randomized experimental design was used, with 4 treatments and 4 replications (7 plants per replication). The treatments were: T1- control treatment; T2- Exal Powder 5 g L-1; T3- Hidro Exal 15 ml L-1; T4- Exal Powder 5 g L-1+ Hidro Exal 15 ml L-1. Six applications were performed (every 15 days). The following were evaluated in the bunch: length (cm), width (cm), weight (g) and number of berries. Using the WineScanTM SO2 equipment (FOSS®, Denmark), the following were evaluated in the must: sugars (g L-1), pH, tartaric acid (g L-1), malic acid (g L-1), gluconic acid (g L-1), ammonia (mg L-1), potassium content (mg L-1). For all treatments and all variables analyzed, no statistical difference was obtained. It is preliminarily concluded that the application of foliar fertilizer based on seaweed (Laminaria japonica) did not influence the analyzed characteristics of the bunch and must of the 'Cabernet Sauvignon' vines. Acknowledgements: To the Company "Algas" América Latina Agricultura Sustentável (ALAS), in the names of its managing partners, Luis Augusto Bennemann de Souza and Fernando Carbonari Collares, for the donation of organic fertilizer composed of Marine Algae (Exal), and for the contribution with some inputs to the execution of this research.