BACTERIA IN MANURE AND ON MANURED AND NPK-FERTILIZED SILAGE CROPS

The numbers of bacteria belonging to Enterobacteriaceae (enterobacteria), lactic acid bacteria, Bacillus- and Clostridium spores were enumerated in manure and on manured and NPK-fertilised silage crops. The enterobacteria were biochemically characterised by means of the Minitek system (BBL). More than 90% of the enterobacteria on crops belonged to the genus Enterobacter. A majority of these (72%) were identified as E agglomerans. Manuring did not increase the number of enterobacteria on silage crops. E coli was the most frequent species in manure but was present at 10(-3) times that of the total number of enterobacteria on the crop one week after manuring. The number of Bacillus spores was 20-40 times higher on manured crops and the number did not decline with time, whereas Clostridium spores, coliforms capable of growing at 44-degrees-C and E coli were reduced 6, 40 and 20 times respectively between manuring and harvesting (7 weeks). Mechanical harvesting increased the number of Bacillus spores and coliforms capable of growing at 44-degrees-C on NPK fertilised crops probably due to soil contamination. Enterobacteria and lactic acid bacteria increased during wilting. The most representative enterobacteria on wilted crops was a specific biovariant, possibly E agglomerans or Rahnella aquatilis.