RECLAMATION OF INCLINED BENTONITE MINING BYPRODUCTS BY HYDROSEEDING IN THE ISLAND OF MILOS

This 2-year research study focuses on the reclamation of bentonite inclined surfaces using hydroseeding in a quarry of the island of Milos. Three types of hydroseeding seed mixes were utilized: a) a mixture from 7 native species of Milos’s island, b) a mixture from 6 commercial species, c) a barley-oat mixture and d) a non-hydroseeded control. The study included two inclined surfaces. The first had a northern while the second had an eastern orientation. Each inclined surface had 12 experimental plots (12-15 m height and 1,5 m width and each experimental plot was subdivided into 3 subplots along the height direction (high, medium, low). Measurements included the total number of plants, the total number of plants per species, the number of invading plants; soil moisture and plant dry weight. It was found that during the 2 years of the study, the number of plants as well as the soil moisture was higher in the northern inclined surface compared with the eastern one. The commercial species mixture provided the highest plant number (66%, 59% and 74% more than native species, barley-oat and the control, respectively). However towards the end of the second year a significant decrease in the number of plants of the commercial species mixture was observed that equalized its plant numbers with the barley-oat mixture. The number of the native mixture was minimal and equal to the non seeded control. In contrast plant number in the barley-oat mixture was reduced by 3% from the first to the second year. The commercial plants mixture provided the most biomass as indicated by the dry weight. The species that provided the highest plant numbers were mainly Lolium rigidum and Avena sterilis. The plant-intruders that were detected without participating in the hydroseeding mixture were Brassica nigra, Salsola kali, Inula viscosa and Mesembryanthemum nodiflorum.