| Sugarcane tops silage can partly alleviate the shortage of winter roughage resources in Guangxi.In this experiment,firstly,the effects of three different fertilizer application(0,150,300 kg/ha)and three different varieties(B9,C22,T11)on the quality of sugarcane tops silage were studied,and the changes of microbial diversity were measured on the 0,2,6,14 days of aerobic exposure.Secondly,under the same nitrogen application and variety,the changes of microbial diversity in the natural silage of sugarcane tops(day 0,2,6,12,20,30,45,60)and after aerobic exposure(day 1,2,3)were compared,which can provide scientific guidance for the rational utilization and silage regulation of sugarcane tops.The results are as follows:1.After 133 days of silage,the crude protein content of B9 group was significantly higher than that of T11 when the nitrogen application was 0 kg/ha(P<0.05).Under the same variety,the higher the nitrogen application level,the higher the protein content.The content of soluble carbohydrates in T11 was significantly higher than that in B9 and C22(P < 0.01)at 0 kg / ha of nitrogen application,and that in C22 was significantly higher than that in B9 and T11(P < 0.01)at 150 kg/ ha of nitrogen application.At any nitrogen application level,the content of NDF and ADF in C22 was significantly lower than that in B9 and T11(P < 0.05).2.After 133 days of silage,the p H of B9 was significantly higher than that of C22(P < 0.05),the lactate content of C22 was significantly higher than that of B9 and T11(P < 0.05),and the ammonia nitrogen content of T11 was lower than that of C22 and B9.After 14 days of aerobic exposure,the p H of B9,C22 and T11 increased significantly at 300 kg/ha(P < 0.05),which were 5.35,6.67 and 5.62,respectively.The content of lactate and ammonia nitrogen in the experimental groups increased significantly.3.Lactobacillus,Escherichia-Shigella and Clostridium were the dominant bacteria in each experimental group on the day 0-6 of aerobic exposure,Lactobacillus,Escherichia-Shigella,Clostridium and Acinetobacter were the dominant bacteria in BD,BZ and CD experimental groups on the day 14 of aerobic exposure,and Lactobacillus,Escherichia-Shigella,Acinetobacter,Lysinibacillus and Paenibacillus were the dominant bacteria in BH,CZ and CH experimental groups.On the d 0 of aerobic exposure,Pleurotus and Fusarium were the main fungi in each experimental group.On the d 2-14 of aerobic exposure,Candida and Pichia were the dominant fungi in each experimental group.4.For variety B9,the amount of nitrogen application was negatively correlated with Clostridium,while the days of aerobic exposure were positively correlated with Lysinibacillus,Paenibacillus and Candida.For variety C22, nitrogen application was negatively correlated with Lactobacillus,Clostridium,Pleurotus and Acremonium,and positively correlated with Bacillus.The days of aerobic exposure were negatively correlated with Escherichia-Shigella,Pleurotus and Fusarium.5.Lactobacillus,Citrobacter and Leuconostoc were the dominant bacteria,Pichia was the dominant fungus in the later stage of silage and aerobic exposure.The Spearman’s correlation analysis showed that Aspergillus,Cladosporium,and Fusarium were positively correlated with Clostridium,Lactobacillus,and Pediococcus,but negatively correlated with the genera Acinetobacter and Serratia.In summary,when the nitrogen application was 150kg/ha and the variety is C22,the content of NDF and ADF are the lowest,and the content of WSC is higher,and p H and the content of ammonia nitrogen are the lowest,and the content of lactic acid is the highest,and the quality of silage is the best.In the process of sugarcane tops silage,Aspergillus and Pichia were the main fungi.Escherichia-Shigella,Pleurotus and Fusarium were the main fungi in the process of aerobic exposure.Therefore,suitable strains of Serratia and Bacillus could be selected to improve the silage quality and aerobic stability of sugarcane tops silage. |
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