Effect of Harvesting Time on Biomass and Combustion Quality of Miscanthus lutarioriparius in Dongting Lake Area

Abstract

Biomass energy is increasingly recognized as a promising alternative to conventional energy sources, offering potential sustainability and environmental benefits. Miscanthus has emerged as a standout candidate within energy crops, with M. lutarioriparius particularly noteworthy. This research delves into the intricate relationship between the timing of harvest and the resulting biomass yield and combustion quality of M. lutarioriparius in the unique coastal wetlands surrounding China’s Dongting Lake. An extensive field experiment was meticulously executed to explore these dynamics, yielding valuable insights comprehensively. (1) First and foremost, the study unearthed a paradoxical trend: delaying the harvest of M. lutarioriparius led to an increase in the stem-to-leaf ratio. However, this apparent benefit was counterbalanced by a noticeable decrease in overall biomass yield, primarily driven by the shedding of leaves as harvest was delayed. Delving into the intricacies of biomass composition, delayed harvests had a significant impact. (2) Specifically, they resulted in marked reductions in water content, ash content, and hemicellulose levels within M. lutarioriparius biomass. The correlation analysis further underscored the importance of cellulose and lignin, with a strong positive relationship between their content and calorific value, while hemicellulose exhibited a highly significant negative correlation. (3) Additionally, the study ventured into the realm of mineral elements within the biomass. Delayed harvesting precipitated a substantial reduction in their content, with notable fluctuations observed in potassium (K) and calcium (Ca) levels. Furthermore, ash content exhibited positive correlations with potassium (K) and silicon (Si) contents, shedding light on the intricate interplay of mineral elements. A notable silver lining emerged despite the reduced biomass yield associated with delayed harvesting. In a holistic assessment, the optimal window for harvesting M. lutarioriparius to maximize fuel quality was pinpointed to span from late November to the conclusion of January in the subsequent year. This nuanced understanding of harvesting timing can play a pivotal role in optimizing the utilization of M. lutarioriparius as a valuable energy resource.