Drip application of a biopolymer-based biostimulant enhances root growth and nutrient uptake of processing tomato

Root growth is often restricted by genetics, cultural factors, and adverse environmental conditions. The application of plant biostimulants can help to promote root growth and to guarantee optimal shoot growth and productivity. An innovative biopolymer-based biostimulant (Quik-Link, Italpollina S.p.A., Rivoli Veronese, Italy) for boosting root growth and improving nutrient uptake by plants was tested in three experiments. In the first experiment, tobacco leaf explants cultured in vitro under Murashige and Skoog basal medium enriched with 1 mL L-1 of Quik-Link showed regeneration of roots while no roots were detected from leaf explants cultured without the addition of Quik-Link in the medium. In the second experiment carried out under greenhouse conditions, tomato plants were transplanted in pots filled with a sandy soil and irrigated after two days from transplanting with a solution containing the biostimulant at three concentrations corresponding to 0, 0.12 or 0.24 mL plant-1. After 12 days from transplanting, tomato plants treated with 0.24 mL plant-1 of biostimulant exhibited a higher root dry biomass and root to shoot ratio than control plants. In the third experiment, carried under field conditions, treatments were defined by a factorial combination of two fertilization levels (conventional and low input fertilization with half-dose of fertilizers used in conventional fertilization plan) and two Quik-Link application rates (0 and 12 L ha-1). Biostimulant application increased marketable yield by 19.2 and 9.7%, under reduced and conventional fertilization regimes, respectively. Quik-Link application increased N, P, and Fe in tomato leaves at flowering/fruit set stage. Fruit quality parameters were only affected by fertilization level with an increase of soluble solids contents with the reduced rate of mineral fertilizers.