Growth and nutrient status of French marigold (Tagetes patula L.) under biostimulant application

The aim of this study was to investigate the influence of biostimulants containing amino acids, humic acids, oligosaccharides and glycosides on the growth parameters and nutrient status of French marigold. The experiments were carried out in the glasshouse and field of the Faculty of Agriculture, University of Banja Luka, during 2009, 2010 and 2011. Young French marigold plants (cultivar 'Hero Orange') were treated with Radifarm (R) or tap water as a control. At the end of May, the seedlings were transplanted into outdoor beds and plants in the treatment group were further treated with Megafol (R), Viva (R) and Kendal (R), while plants in the control group continued to only receive tap water. At the end of the experiment, the following parameters were recorded for each plant: plant height (cm), plant diameter (cm), flower diameter (cm), number of flowers, fresh and dry weight (g), and concentrations of total nitrogen, phosphorus, potassium, calcium and magnesium in the roots and above-ground parts. It was found that the application of biostimulants increased the quality of these ornamental plants by improving their ability to overcome temperature stress and their nutrient uptake from the soil, which would reduce the need for fertiliser application and consequently environmental contamination.