ISHS Acta Horticulturae 691: International Conference on Sustainable Greenhouse Systems - Greensys2004
MANAGEMENT OF BACTERIA TO IMPROVE SLOW FILTRATION EFFICIENCY IN TOMATO SOILLESS CULTURE |
| Authors: | P. Rey, F. Déniel, A. Guillou, S. Le Quillec |
| Keywords: | Bacillus cereus, Fusarium oxysporum, Pseudomonas fluorescens, Pythium spp. |
| DOI: | 10.17660/ActaHortic.2005.691.41 |
| Abstract:
In tomato soilless culture, slow filtration allows one to control the development of diseases caused by pathogenic micro-organisms. In this study, columns of two filter units were inoculated with 5 selected bacteria (3 strains of Pseudomonas putida and 2 of Bacillus cereus). One of the two filters had been inoculated a year before the other, but both series of analyses were conducted on the same year. Fungal elimination (Fusarium oxysporum and Pythium spp.) was usually successful at about 98 to 99.9% all over the cultural season after one year and two years of filtering by the two systems. Bacteria populations were generally more numerous onto the different layers of pouzzolan grains in the two-year-old filter than in the one-year-old filter. High biological activity was detected at a 40-cm depth from the top in the two-year-old filter; in the other one it was found only at 20 cm. This high colonisation of the filtering medium by bacteria coincided with the removal of fungi from the solution flowing through the columns. Therefore, the biological activation of filter units constitutes a reliable method to standardise slow filtration efficacy. | |
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