The Effect of Plant Stimulant/fertilizer “resistim” on Growth and Development of Strawberry Plants

In intensive fruit production, in order to obtain high yields, it is necessary to use high fertilization rates as well as plant protection products. An alternative to that kind of production is presented by natural stimulators of plant growth and development called biofertilizers, biopreparations, biostimulators or phytostimulators. They are preparations of natural (plant or animal) origin, harmless to humans and the environment. Biostimulators contain biologically active substances, i.e. plant hormones, enzymes, macroand microelements, and other compounds that stimulate the growth and development of plants. New approaches to agriculture tend to use environmentally friendly and safe products with a broad spectrum of activity. Nowadays many preparations offered for crop production are designed not only to fertilize the plants and stimulate their growth, but also to protect them from diseases or pests. Phosphite-containing products act as fertilizers or fungicides, and sometimes as biostimulants. “Resistim” is an activating stimulant and fertilizer composed of a potassium phosphite and natural betaines. The aim of the study was to evaluate the influence of “Resistim” on the growth and development of three strawberry cultivars (Fragaria x ananassa Duch.). Two of them are short-day cultivars: ‘Honeoye’ and ‘Elsanta’, while ‘Selva’ is a day-neutral cultivar. The experiment was established in October 2008 under controlled conditions in a glasshouse and was carried out for three months. The plants were planted into a mixture of sandy mineral soil and peat in rhizoboxes enabling visualization of root growth and development. The plants were fertilized with standard NPK fertilization (N – 1.02 g, P – 1.9 g, K – 0.78 g per rhizobox), “Resistim” at the dose of 0.2% and 0.4% and NPK (N – 1.02 g, P – 1.9 g, K – 0.78 g) with “Resistim” at the dose of 0.2% and 0.4%, and