生物质炭对酸性菜地土壤氮素矿化和N_(2)O排放的影响

Effects of Biochar on Nitrogen Mineralization and N_(2)O Emission in Acid Vegetable Soils

N_(2)O是受人类活动影响的温室气体,土壤中硝化和反硝化作用是N_(2)O产生的主要过程,施用生物质炭影响土壤氮素矿化过程和N_(2)O排放。本研究以广州近郊菜地土壤为研究对象,在施氮肥和不施氮肥情况下,分别施加3%和6%的稻壳炭(RB)、棕榈丝炭(PB),进行室内培养试验,研究不同生物质炭和施入量对酸性菜地土壤氮素矿化和N_(2)O排放的影响。研究结果表明,施氮处理菜地土壤氮素矿化量和土壤N_(2)O累积排放量最大,分别达到153.6 mg/kg和383.7μg/kg,添加生物质炭显著降低了菜地土壤氮素矿化量和土壤N_(2)O排放量(P<0.05),生物质抑制了菜地土壤氮素矿化过程,降低了土壤中硝态氮和铵态氮含量,从而抑制了土壤N_(2)O的形成和排放,抑制程度随生物质炭添加量增加而增强,不同类型生物质炭作用不同,稻壳炭(RB)抑制作用大于棕榈丝炭(PB)。

N_(2)O is a greenhouse gas affected by human activities.Nitrification and denitrification in the soil are the main processes of N_(2)O emission.The application of biochar affects the soil nitrogen mineralization process and N_(2)O emission.To study the effects of biochar on nitrogen mineralization and N_(2)O emission,the acid vegetable soil in the suburbs of Guangzhou province was adopted for incubation experiment,and rice husk biochar(RB)and palm silk carbon(PB)were applied at 3%and 6%respectively with and without nitrogen fertilizer.The results showed that the amout of nitrogen mineralization and N_(2)O emission in nitrogen fertilizer treatment were the largest,reaching 153.6 mg/kg and 383.7μg/kg,respectively.The addition of biochar significantly reduced the soil nitrogen mineralization and soil N 2O emissions(P<0.05).Biochar inhibited the nitrogen mineralization process and reduced the content of nitrate nitrogen and ammonium nitrogen in the soil,and thus suppressed the formation and emission of N_(2)O in the soil.The inhibition degree increased with the increase of biochar addition.Different kind of biochar had different effects,and the inhibition degree of rice biochar(RB)was greater than that of palm silk biochar(PB).