Deficit irrigation and biostimulants’ use for the alleviation of drought effects on processing tomato
A direct result of the ongoing climate change is the reduced availability of irrigation water required to meet the needs of crops. The aim of the present study was to evaluate the effects of the application of biostimulants on the growth and quality of processing tomatoes (Lycopersicum esculentum L. cv. Heinz 1162) under conditions of deficient irrigation. For this purpose, five biostimulants formulations were implemented (Μ1: Vegetal proteins and amino acids + Carboxylic Acids, Μ2: Vegetal proteins and amino acids + Seaweed extracts (Laminaria digitata + Ascophyllum nodosum), Μ3: Humic & Fulvic Acids + Seaweed extracts (Laminaria digitata + Ascophyllum nodosum), Μ4: SiO2, including the untreated control), while at the same time two levels of irrigation were applied (100%, 65-70% of maximum field capacity). The results indicated positive effects of biostimulants on the number and weight of fruit per plant, as well as on total fruit yield, especially in the case of Μ3 treatment under normal irrigation. The application of biostimulants at deficit irrigation conditions had a beneficial effect on total fruit yield, especially in the case of M1 treatment. M3 treatment had a positive effect on fruit visual appearance since it reduced the Blossom End Rot (BER) symptoms compared to the control treatment. A noteworthy effect was the significant increase of Total Soluble Solids content (Brix °) of fruit juice under deficit irrigation, especially for M4 treatment.