Browsing by Subject "fermentation quality"

The aim of this study was to investigate the esilability of white lupin (Lupinus albus) and spring wheat (Triticum aestivum) bi-crop when ensiled as a whole-crop. There were two plant mixture ratios and two growth stages in the study. Silages made with different additives were compared with untreated silages, which were as a control. The experimental silages were made at the research farm of the University of Helsinki in Viikki on August 13th and 27th, 2012. At the first growth stage (K1) wheat was at the beginning of dough stage and the pods of white lupin were green and the seeds filled 50 % of space between septa. At the second growth stage (K2) wheat was at the end of dough stage and the seeds filled 75 % of space between septa. After mowing plant species were separated and two ratios were formed. The first ratio comprised 1/3 white lupin and 2/3 wheat and the second 2/3 white lupin and 1/3 wheat of fresh weight. The additive treatments were: 1) without additive (untreated), 2) formic acid (4 l/t as a 100% acid), 3) the mixture of sodium nitrite (0,75 kg/t) and hexamine (0,5 kg/t) and 4) Lactobacillus plantarum 1x106 cfu/g. Silages were ensiled in the laboratory scale silos in triplicate. Silos were opened after 100 days of ensiling. The chemical composition of raw material at harvest and the fermentation characteristics and aerobic stability of silages were determined in the experiment. The dry matter content of plant mixtures was about 220 g/kg in the mixtures with higher proportions of lupin and about 300 g/kg in the mixtures with higher proportions of wheat. The preservation of silages were impeded by the low dry matter content and high buffering capacity of white lupin, the low sugar content of the mixtures and clostridial contamination. As the proportion of lupin increased the crude protein and sugar content of the mixture increased but the ensilability of the mixture declined. Preservation without additive produced low quality silages in all silage batches. High amounts of ammonia, butyric acid and other fermentation acids typical of bad silage fermentation were detected in the untreated silages. The fermentation quality was good in silages made with Lactobacillus plantarum at the first growth stage when the raw material was dryer and the sugar content of mixtures were higher. Based on the butyric acid and ammonia concentrations the use of Lactobacillus plantarum resulted in poor quality silages at the second growth stage. The dose of formic acid in this experiment wasn’t probably high enough in regard to the poor ensiling properties of raw material and clostridial contamination. High amounts of butyric acid were detected in all silages treated with formic acid. At the second growth stage the ammonia concentrations were also high. The most effective additive in the experiment was the mixture of sodium nitrite and hexamine resulting in good fermentation quality in all silage batches. No butyric acid was detected from the mixtures with higher proportions of wheat and amounts were extremely low also in the mixtures with higher proportions of lupin. Most of the silages were aerobically stable during 13 days of the period of measurement. Only a few silos (5 out of 48) were aerobically deteriorated and those silos were very unstable as the warming was noticed within 2 days. Most of the deteriorated silos (4) were treated with biological additive. Based on the present results the ensiling of white lupin-wheat whole-crop silage is difficult. The composition of raw material suggests that silage should be made from the mixture where the proportion of lupin is higher and cut at the earlier growth stage if the maximization of crude protein and sugar content is wanted. However, the ensilability of raw material is more difficult on the basis of dry matter content and buffering capacity. The yield is also lower than later in the growth stage. Silage additive should always be used when ensiling white lupin. The mixture of sodium nitrite and hexamine was the most effective additive in the study.