不同施肥模式下硝化抑制剂DCD与生物炭对菜地N2O排放r和土壤特性的影响

摘要

Field experiment was conducted with static chamber and gas chromatography method to study the effects of DCD and biochar (BC) on N2O emission and soil properties under different fertilization modes in vegetable field. The experiment included two fertilization models: single chemical fertilizer nitrogen (CF) and organic fertilizer instead of 25％ chemical fertilizer nitrogen (MF), and the trial was consisted of six treatments: (1) CF; (2) CF combined with DCD (CFDCD); (3) CF combined with biochar (CFBC);(4) MF; (5) MF combined with DCD (MFDCD); (6) MF combined with biochar (MFBC). Results showed that compared with CF, MF significantly reduced accumulated N2O emission and nitrate nitrogen content by 46.9％ and 30.7％, respectively, under the condition of the same nitrogen (N) nutrient with 225 kg?hm-2. A highly significant linear correlation was existed between seasonal total N2O emission and 0～15 cm soil nitrate nitrogen content after Chinese flowering cabbage harvest. The results also implied that organic fertilizer replaced part of chemical N could change N exists in form and the transformation path of N in soil to some extent. The application of DCD or BC under CF condition in comparison with CF treatment significantly reduced N2O emission of Chinese flowering cabbage field by 72.8％ and 38.8％, respectively, while reducing N2O emission by 44.9％ and 10.3％, respectively, compared with MF treatment. The N2O emission reduction effects of DCD was better than that of BC under this experimental situation and the N2O emission reduction effects of BC treatment performed more significantly under CF than MF condition. Besides, DCD and BC effectively reduced the accumulation of soil nitrate nitrogen. And 0～15 cm layer soil ammonium nitrogen in DCD treatment was kept in a high level compared with other treatments in the same mode. In conclusion, organic fertilizer replaced part of chemical N and the addition of DCD, BC effectively inhibited the release of N2O and reduced soil nitrate N level, which provided reference for regulating and controlling greenhouse gas emissions in vegetable field.%通过田间试验,采用静态箱-气相色谱法研究不同施肥模式下硝化抑制剂(DCD)和生物炭对菜地土壤氧化亚氮(N2O)排放及土壤特性的影响.试验包括单施化肥氮与有机肥替代25％化肥氮2种施肥模式,共设6个处理:(1)单施化肥氮(CF);(2)单施化肥氮&DCD(CFDCD);(3)单施化肥氮&生物炭(CFBC);(4)有机肥替代25％化肥氮(MF);(5)有机肥替代25％化肥氮&DCD(MFDCD);(6)有机肥替代25％化肥氮&生物炭(MFBC).研究结果表明,施氮量为225 kg?hm-2条件下,有机肥替代25％化肥氮处理较单施化肥氮处理显著降低了菜地N2O累积排放量和土壤硝态氮含量,降幅分别为46.9％和30.7％.整个菜心季土壤N2O总排放量与收获季0～15 cm土层土壤硝态氮含量之间呈极显著的线性正相关关系,表明有机肥部分替代化肥氮一定程度上改变了土壤中氮素营养的存在形态及氮转化路径.CFDCD和CFBC处理较CF处理显著降低了土壤N2O排放,降幅达72.8％和38.8％,MFDCD和MFBC较MF处理土壤N2O排放减少了44.9％和10.3％,表明在本试验条件下,DCD处理抑制菜地N2O排放的效果相对高于生物炭处理,而生物炭抑制菜地N2O排放的效果在单施化肥氮模式下表现得更明显.与此同时,DCD和BC配施处理均有效降低了土壤硝态氮的积累,且DCD处理在整个菜心生长季0～15 cm土壤铵态氮含量明显高于相同施肥模式下的其他处理.综上可知,有机肥部分替代化肥氮模式、生物炭与DCD的添加均能有效抑制菜地土壤N2O的排放并降低土壤硝态氮水平.本研究结果可为调控菜地土壤N2O气体排放提供提供参考.