[Fermentation process during the ensiling of green forage low in nitrate. 1. Fermentation process in untreated green forage].

The fermentation process of ensiling green forage, low in nitrate, was proved in 8 experiments with ryegrass, ochardgrass and grass-legumes mixture. It was demonstrated that also in easily fermentable green forage the absence of nitrate promote the occurrence of butyric acid simultaneously with the lactic acid fermentation even at an early stage of fermentation. It is supposed that the lack of nitrate as a natural inhibitor of clostridia leads to early formation of butyric acid. The evolution of clostridia in the beginning of the fermentation process was more rapid than expected. It seems that easily soluble carbohydrates are the substrates of butyric acid formation. That is why in green forage, low on nitrate, clostridia act as food competitors for lactic acid bacteria. Amino acids were not degraded in the early stage of fermentation. In spite of the high content of butyric acid the amount of ammonia was low. Apart from n-butyric acid volatile fatty acids > or = C4 did not occur. The lactic acid formation reached only a restricted extent, also in green forage with a high content of sucrose. It was assumed that there are differences in ensilability of carbohydrate fractions between forage plants.