生物炭添加对猪粪堆肥过程碳素转化与损失的影响

堆肥是最合适的处理农业废弃物的技术之一,但在堆肥过程中,碳素的损失及温室气体的大量排放引起越来越多的关注.因此,如何减少堆肥过程中碳素损失成为堆肥面临的重要问题.本研究以猪粪等为原料,利用强制通风反应箱研究了生物炭添加对堆肥过程中碳素转化及碳素损失的影响.结果表明,在堆肥过程中总有机碳呈下降趋势,添加生物炭处理的总有机碳含量提高了6.69%~20.60%;可溶性有机碳的变化规律与总有机碳相似.腐殖质碳含量呈先下降后上升的变化趋势,添加生物炭处理的腐殖质碳含量下降了0.39%~14.97%;腐殖化系数(胡敏酸/富里酸)与生物炭添加量成正比,说明生物炭添加有利于堆肥的腐熟.至堆肥结束,堆料干物质失重率为23.51%~30.91%,碳素损失率为20.71%~28.85%,添加3%生物炭的处理干物质失重率与碳损失率均最高,添加9%生物炭处理均最低.

Effects of biochar addition on carbon transformation during composting of pig manure

Aerobic composting is an effective way to treat and recycle agricultural waste materials. However, the aerobic composting is a potential source of greenhouse gases to the atmosphere, which closely relates to the global climate change. Therefore, control of carbon loss in the process of aerobic composting should be primarily considered. An experiment was conducted to study the effect of different biochar additions on carbon transformation and carbon loss in composting of pig manure by using static forced-air composting boxes. The results showed that total organic carbon (TOC) in the composts decreased with the increase of composting time. TOC in the treatments with biochar addition increased by 6.69%~20.60% than that of the control treatment. TOC and water-soluble organic carbon (WSOC) exhibited a similar trend throughout the composting. Humus carbon content (HC) first decreased and then increased with composting time. HC in the treatments with biochar addition decreased by 0.39%~14.97% with respect to the control treatment. The ratio of humus acid to fulvic acid was proportional to the amount of the biochar added, which indicated that biochar addition was beneficial to pig manure composting. The weight loss rates of the composted materials were 23.51%~30.91% at the end of composting, and the carbon loss rates were 20.71%~28.85%. The loss rates of weight and carbon were the highest in the treatment with 3% biochar addition, and were the lowest in the treatment with 9% biochar addition.