ENSILING OF MANURED CROPS - EFFECTS ON FERMENTATION

The quality of silage from crops fertilized with cattle manure and an inorganic fertilizer was compared in experiments from 1985 to 1989. Ma nure was spread either as farmyard manure (FYM, 25 t ha-1) or as slurr y (20-50 t ha-1). Crops were direct cut (approximately 200 g DM kg-1) or wilted (approximately 300 g DM kg-1), precision chopped and ensiled in experimental silos. Silage was treated with 4 kg 85% formic acid t -1 fresh matter (FM), an inoculant or no additives. The use of manure, particularly FYM, resulted in more Bacillus spores on crops at harves t compared with fertilized crops. Clostridium spores increased as a re sult of manuring in 1989 only on FYM-treated crops. Differences in the chemical composition of crops were usually small between fertilizer t reatments. The quality of silage from slurry-dressed crops, compared w ith that of silage from fertilized crops, varied between years. The FY M resulted in reduced silage quality, i.e. high pH values (> 4.5), hig h ammonia N (> 150 g kg-1 total N) and butyric acid (> 6.3 g kg-1 wate r) concentrations, and high numbers of Bacillus (10(5) g-1 FM) and Clo stridium spores (10(5) g-1 FM). The concentration of lactic acid was l ow (less-than-or-equal-to 12 g kg-1 water). Wilting and additives gene rally improved silage quality and reduced the differences between trea tments. However, the efficiency of the inoculant on farmyard manured c rops was limited.