SEASONAL-CHANGES OF EPIPHYTIC MICROORGANISMS ON MANURED, NPK-FERTILIZED AND NOT FERTILIZED FORAGE

During the vegetation period of the years 1991-1994 and 1991-1992, respectively, changes of epiphytic micro-organisms were closely monitored on manured and NPK-fertilised forage and compared with a grassland plot without any fertilisation. Counts of aerobic bacteria, of yeasts and moulds as well as of enterobacteria were apparently not affected by climatic factors or by manuring. Their numbers increased with plant age. Only plants from intensively NPK-fertilised plots showed slightly higher total counts of bacteria. Numbers of bacteria and fungi on different plants of the same plot were quite similar. Though enumeration of micro-organisms on different plant parts showed varying counts at least in an early stage of their seasonal development. As a result of manuring, the numbers of Clostridium spares, coliforms and E. coli increased on standing crop. Their numbers reduced with time, so that manured crops at the ensiling stage can be expected to show only small numbers of Clostridium spores, coliforms and E. coli originating from manure. Grassland soils, independent of manuring, are natural habitats of silage spoilage organisms, especially the counts of Clostridium spores in soils exceed those of standing crops by far. The flora of lactic acid bacteria varied in quantity as well as in composition of genera depending on different climatic factors and on manuring as well as on part and age of plants. Further ecological studies will be necessary in order to explain the high variability within the epiphytic lactic acid bacteria flora.