The publication aims to present some knowledge about the less-known but at the same time very scarce bituminous rock alginite with comprehensive practical use in the form of a brief overview. Alginite is an organic-bituminous rock that was formed about six million years ago from dead fossil algae Botryococcus braunii Kütz and diatoms in the area of today's Pannonian Basin. In Europe, alginite deposits have been discovered in Hungary, Austria and Slovakia in Pinciná village. Alginite mining is mostly used in Hungary in the Gerce area. Alginite is grey to dark grey, in the wet state dark laminated, clayey with the form of disintegrating clay. Alginite has very valuable physical, mechanical and chemical properties. It is a natural bituminous rock with a favourable content of basic nutrients (P, K, Ca, Mg and S) for plants except for nitrogen content. Alginite contains a large number of microelements, which increase the agrochemical possibilities of its use. It can be applied in its natural form without chemical treatment. It is an ecological raw material that improves the soil and does not negatively affec the environment. Alginite has become the subject of research in many workplaces. The overview presents the basic physical, mechanical and chemical properties of alginite and selected knowledge and research results that have enabled the practical use of alginite in natural or technologically modified form in agriculture in the formation of growth, development and crop formation and quality of seeds and fruits of cultivated crops, forestry, remediation and improvement of soil and water properties, decomposition of herbicides, stabilization of beneficial microorganisms in animal organisms and other areas.

The aim of the research is to determine the effect of application of the developed product (extract) called ALGEX r 6 from natural mineral rock alginite in two different watering periods on the formation of root biomass and aboveground plant biomass of a selected group of medicinal plants (Melissa officinalis L., Malva verticillata L. and Ocimum × citriodorum Vis.) and determining the antioxidant activity in dried leaves and whole plants in aqueous and methyl alcohol extracts by DPPH method. The experiment was established in the Botanical Garden at the Slovak University of Agriculture in Nitra throughout 2020. ALGEX r 6 was prepared by a research team at the Slovak University of Agriculture in Nitra in the form of an extract from the natural mineral rock alginite with an application of thermal and chemical treatment. In the experiment, ALGEX r 6 was applied in the form of a watering in two variants with the same concentration of 3 % solution in 2 decilitres of water, but various application in terms of days in the pre-harvest stage of the above-ground plant biomass of 30 individual plants from each species. There are two diametrically opposite trends of ALGEX r 6 application that are manifesting themselves in M. officinalis and M. verticillata by reducing the root and above-ground part biomass compared to the control variant. The percentage proportionality of root/ above-ground part biomass in M. officinalis decreased from 62.48/30.31 % (control), to 45.57/18.85 % (variant 1) and to 36.07/17.27 % (variant 2), as well as in M. verticillata the root/above-ground part biomass decreased from 16.03/13.93 % (control), to 14.97/9.42 % (variant 1) and to 11.61/10.14 % (variant 2). In the species Ocimum × citriodorum Vis. the opposite trend manifested. The application of ALGEX r 6 watering resulted in increasing the antioxidant activity on the tested plant parts, especially in aqueous extracts in M. officinalis (from 19.30/control to 33.61 %/variant 1, 2), also in O. citriodorum (from 26.56/control to 44.16 %/variant 1), while in methyl alcohol extracts, the antioxidant activity showed a slight increase in all tested species.

KOVÁR, P., VOZÁR, Ľ., JANČOVIČ, J.: The turfs quality of selected Slovak varieties of the genus Festuca under the conditions without irrigation. Acta univ. agric. et silvic. Mendel. Brun., 2012, LX, No. 6, pp. 181-188

KOVÁR PETER, VOZÁR ĽUBOŠ, JANČOVIČ JÁN:The infl uence of water extracts of selected turfgrass species on germination and initial growth of Poa annua L. Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, 2013, LXI, No. 3, pp. 677-681 The eff ect of Lolium perenne L., Festuca rubra L., Festuca arundinacea Schreb., Poa pratensis L. and Poa annua L. aqueous extracts on germination rate and total germinability of Poa annua L. seeds and length of Poa annua L. leaves and roots was studied in a laboratory experiment. Germination of seeds was conducted in the growth chamber at the light and temperature regime -day/night -12/12 hours, 23/15˚C, rh 70 %, for 42 days. Extracts signifi cantly aff ected the total germinability and germination rate of Poa annua L. seeds (p = 0.000). The lowest germinability (27.3 ± 7. 1 %) and germination rate (0.7 ± 0.2 seeds per day) had Poa annua L. seeds germinated in Poa pratensis L. aqueous extract. Used extracts (except for Festuca rubra L. extract) had signifi cantly inhibitory eff ect on length of Poa annua L.

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