生物质炭对伊乐藻堆肥过程氨挥发的作用效应研究

针对水生植物堆肥过程中氮素损失严重的现状,探讨以生物质炭为添加剂的堆肥体氨挥发控制技术,以伊乐藻和稻草为供试材料,采用静态高温好氧堆肥的方法,在生物质炭不同添加比例条件下,监测了伊乐藻与稻草混合堆置过程中氨挥发及其影响因素的变化动态。结果表明:整个堆肥过程中,氨累积挥发量与生物质炭添加比例关系密切(P0.01),与不添加生物质炭的常规对照处理相比,添加比例为5%、10%的处理增加了氨的累积挥发量,而添加比例为15%、20%的处理降低了氨的累积挥发量;不同堆肥时间段,生物质炭不同添加比例处理0~3 d的氨累积挥发量均大于对照,4~6 d的氨累积挥发量,除添加比例5%处理外,均小于对照;伊乐藻堆肥体的氨挥发速率与堆温、铵态氮含量具有显著的偏相关性,其偏相关性均达到P0.05的显著水平;增加生物质炭添加比例,不仅提高了堆肥温度,对堆肥体的氨挥发损失具有负向的促进作用,同时也降低了堆肥体的铵态氮含量,对堆肥体的氨挥发损失具有正向的抑制作用,生物质炭对伊乐藻堆肥体氮素的氨挥发损失具有促进与抑制双重性的作用效应。

Effects of Biochar on Ammonia Volatilization During Elodea Nuttallii Composting

Aquatic plants used in control of water eutrophification are rich in nitrogen(N), phosphorus(P), potassium(K), and micronutrients, and can be used as good organic fertilizer after composting. However, composting process often causes losses of N through ammonia(NH₃) volatilization. Biochar has been shown to act as an absorber of NH₃ and water-soluble NH₄⁺ and might therefore reduce losses of N during composting of aquatic plants. Here a composting experiment with aquatic plants and rice straw was carried out under static pile composting with natural ventilation to study the effect of biochar at varying rates on NH₃ volatilization reduction and influencing factors. Biochar addition significantly affected accumulated NH₃ volatilization(P<0.01). Compared to the CK(no biochar addition), NH₃ volatilization was increased by biochar at 5% and 10%, but decreased by biochar at 15% and 20%. During the first three days of composting, amount of NH₃ volatilization was higher in biochar addition than in the CK, while during 4~6 days of composting, NH₃ volatilization was lower in biochar than in the CK. A significant partial correlation existed between NH₃ volatilization rates and compost temperature & ammonium nitrogen(P<0.05). These results show that biochar has two way effects on NH₃ volatilization during composting aquatic plants by either decreasing NH₃ volatilization through enhancing NH₄⁺ adsorption, or increasing NH₃ volatilization via raising the reactor temperature during composting.