Application of innovative biostimulants for growth and quality improvement in vegetable and ornamental crops

Abstract

Research objective: This research aims to evaluate the biostimulant potential of some innovative products that can improve germination, growth and protection from biotic stresses on some vegetable and ornamental species. Materials and Methods: The experiments, which started in October 2022, were conducted in the CREA-OF greenhouses in Pescia (Pt), on Cichorium intybus and Crassula rupestris plants. The experimental groups were: i) group control, irrigated with water and previously fertilised substrate; ii) biofertiliser Ecklonia maxima, dilution 1:1000, 5 ml of this dilution once a week per plant; iii) Elixir lite, irrigated with water and substrate previously fertilised; iv) Immuno pro group, irrigated with water and substrate previously fertilised; Harvest boost group, irrigated with water and substrate previously fertilised. On 23 January 2024, plant height, number of leaves, vegetative weight, root volume and length, number of microorganisms and pH of the substrate were determined. In addition, the mortality of the plants in the nursery was assessed. Results and Discussion: The experiment showed that the use of biostimulants can significantly improve the vegetative and root growth of Cichorium intybus and Crassula rupestris plants. In general, a significant increase in plant height, vegetative and root weight and root length was observed, particularly in the Elixir lite treatment. There was also a significant increase in the microbial colonisation of the substrate with all innovative biostimulant treatments, while the pH remained practically unchanged. The Immuno pro treatment was the best in terms of reducing plant mortality in all two plant species. Biostimulants are widely used in horticulture because we often work with short-cycle crops, varying from a few weeks to a few months. The rapid succession of different crops implies a constant supply of nutrients and intensive use of soil. More intensive horticulture in particular often benefits from the effect of biostimulant treatments due to the increased resource use efficiency of the crops. Foliar biostimulants are mainly used by farmers to increase the production of both leaf and fruit vegetable crops. The positive effects of their use are exerted both on increasing the content of secondary metabolites and on a general improvement of nutrient uptake efficiency. These biological effects can be attributed to the presence in biostimulants of polysaccharides, extracted from algae, such as alginates and carrageenan, which are responsible for two important biological actions: sequestering or slowly releasing nutrients. In fruit vegetables, biostimulants can also improve the homogeneity of flowering and fruit size, as reported for peppers. Commercial biostimulants have increased the unit yield of many leafy vegetable species by acting on nutrient uptake by the plant. Conclusions: In horticultural production, in open field and in protected crops, the application of biostimulants is aimed at achieving one or more of the following objectives: to favour a rapid emergence of seedlings in direct sowing crops or a rapid overcoming of the transplanting crisis; to precociate the entry into production; to increase growth, flowering, fruit set and fruit growth; to improve product quality; to increase the efficiency of nutrient use and tolerance to environmental stresses.