芦竹青贮特性及其对厌氧消化性能的影响研究

Ensilage Performance and Subsequent Anaerobic Digestion of Giant Reed

青贮是一种传统的青绿饲料作物贮存方法,逐渐地被应用于沼气化原料的贮存。以能源作物芦竹为原料,探讨两个不同时间收获(早收、晚收)芦竹在未添加尿素和尿素辅助青贮90 d过程中的化学组分变化及其后续厌氧消化产甲烷性能。结果表明:早收芦竹中水溶性碳水化合物(WSC)质量分数为2.80%(干基),青贮干物质(DM)损失率为8%,而尿素辅助使青贮DM损失降低了28.0%,木质素降解率提高了101.3%,且后续厌氧消化累积甲烷产量提高了25.6%;晚收芦竹中WSC质量分数为4.94%(干基),青贮与尿素辅助青贮的DM损失率均保持在1%左右,但尿素辅助使青贮90 d过程中乳酸累积产量增加了237.5%,木质素降解率提高了43.8%,厌氧消化累积甲烷产量提高了17.4%。因此,早收芦竹WSC含量低而不利于青贮,尿素辅助能有效降低芦竹青贮DM损失和提高后续产甲烷性能。

Ensilage is a traditional technology for green fodder crops storage,which is gradually used in the storage of raw materials for biogas production.The energy crop of giant reed harvested at two different times was used as material for ensilage and conducted for a period of 90 days.Changes in chemical composition and subsequent methane production of ensiled giant reed by anaerobic digestion were examined.The results showed that the difference in water soluble carbohydrate(WSC)content of giant reed caused by harvest time was the main reason for the difference in performance of giant reed ensilage.The WSC content was 2.80%of dry matter(DM)for the giant reed of early harvest(end of August).There was no accumulation of lactic acid during ensilage of early-harvested giant reed,and also urea addition reduced the DM by 28.0%and significantly enhanced by 101.3%of lignin degradation during the whole ensilage.The WSC content achieved 4.94%DM for the giant reed of late harvest(early October),and the DM loss was about 1%during 90 days’ensilage.The cumulative production of lactic acid was increased by 237.5%,and the lignin degradation was increased by 43.8%for late-harvested giant reed via urea-assisted ensilage.Compared with non-ensiled giant reed,the cumulative methane production of early-harvested and late-harvested giant reed via 90 days’urea-assisted ensilage were increased by 25.6%and 17.4%during anaerobic digestion,respectively.Therefore,early harvest led to a low content of WSC and an undesirably ensilage,whereas urea-assisted treatment can effectively reduce the ensiled DM loss and improve the subsequent methane production of giant reed.