Effects of varying doses of Frisol on European ash (Fraxinus excelsior L.) planted on spoil banks

Frisol forte (FR F) and Frisol active (FR A) are slow-acting organic fertilisers recommended for reclamation and revitalisation of undeveloped soils and degraded areas. Tentative results of experiments carried out with these products on spoil banks in the CR showed controversial reactions of plants - on the one hand a high mortality of seedlings and a very good growth on the other. Reasons for these disproportions projecting themselves into the welfare of woody plants probably lie in an incorrect dosage of products. Thus, a special long-term experiment was established with the objective to find an optimal dosing to be used in practice for the reclamation process on spoil banks. By the method of measuring and statistical evaluation of height and stem diameter growths it was discovered that the best results were achieved by the combined use of both products with a dosage in the range of 30-60 g FR F + 250 ml FR A/5 l of water/10 seedlings. The discovered dosage is lower than that indicated by the manufacturer and literature. The application of granulated FR F alone was not so effective. The best dosage in this case was also 60 g/seedling. A disadvantage of using the combination of both types of Frisol is that the water required for dissolving the FR A liquid concentrate is not always available in the location being reforested.