生物质炭对蔬菜废弃物堆肥化过程氮素转化的影响

为了研究添加生物质炭对蔬菜废弃物堆肥化处理过程中氮素转化特征的影响,分析堆肥过程中氮素的转化及损失规律，用西红柿茎蔓、玉米秸秆和猪粪按一定比例混合后添加不同比例的生物质炭，进行了为期30 d的堆肥发酵试验。结果表明，添加生物质炭能够提高堆体温度，使堆体快速进入高温期，延长高温持续时间，可降低挥发性氨的累积释放量，减少堆肥过程中的氮素损失，从而提高堆肥产品全氮的含量，并可促进堆肥后期NH+4-N向NO-3-N转化，提高非酸水解态氮的含量。添加生物质炭有利于堆肥的腐熟，在堆肥第18 d添加较高比例的生物质炭的处理其NH+4-N/NO-3-N≤0.5，堆肥产品达到腐熟。综合保氮和腐熟效果，蔬菜废弃物在堆肥化过程中以添加10%的生物质炭为最佳。

Effect of biochar on nitrogen transformation in vegetable wastes during composting

Aerobic composting is an effective way to dispose vegetable wastes. However, nitrogen losses in vegetable wastes during compost-ing greatly decrease the effectiveness of compost fertilizers. Here the effect of biochar on nitrogen transformation in vegetable wastes was in-vestigated in a 30 day composting experiment using tomato plants, corn stover and swine manure mixture amended with different rates of biochar. Results showed that additions of the biochar had the compost pile enter into the high temperature phase earlier, extended the high-temperature duration, and decreased NH3 emissions and nitrogen losses, thus increasing total nitrogen content in the composted products. Adding biochar also promoted transformation of NH+4-N to NO-3-N(nitrification process)at the late stage and improved the content of unhy-drolysable nitrogen. In addition, applying biochar facilitated compost maturing and lowered the ratio of NH+4-N/NO-3-N to≤0.5 on the 18th day. Based on the present results, the optimum rate of biochar addition for nitrogen conservation and compost maturity would be about 10%.