| 不同量碳源输入梯度下果园排水沟底泥氮素反硝化与N2O排放研究 |
| 摘要点击 2139 全文点击 1038 投稿时间：2015-12-02 修订日期：2016-03-05 |
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| 中文关键词 碳输入 碳氮比 反硝化 N2O排放 累积排放量 |
| 英文关键词 carbon input carbon nitrogen ratio denitrification N2O emission accumulative emissions |
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| 中文摘要 |
| 果园是太湖地区重要的经济作物,但是氮肥投入量大,氮素损失严重,使得排水沟道的活化氮浓度高,碳氮比下降,碳源可能是影响沟道底泥硝化与反硝化作用的限制因子.因此,采集了果园排水沟道沉积物,在实验室条件下,设计了C0、C1、C2、C3、C4这5种有机碳源(葡萄糖)浓度水平,分别为0、5、25、50和100 mg·L-1,同时分别输入了5 mg·L-1的硝酸钾溶液.采用乙炔抑制法来研究果园排水沟道土壤的反硝化损失和不加乙炔研究N2O的排放量.结果表明,加入碳源使土壤的反硝化速率(DN)和N2O排放速率均有一定的增加,碳氮比对N2O排放速率和DN的影响均极为显著(P<0.05);碳氮比为10:1时,累积反硝化损失总量和N2O累积排放总量均较大(分别为319.26μg·kg-1和6.20μg·kg-1),占净氮的输入量比例均较高(分别为1.28%和0.02%),说明该处理情况下虽然对于沟道反硝化非常有利,利于去除土壤底泥中富集的氮素,但同时也增加了温室气体N2O的排放. |
| 英文摘要 |
| The orchard is an important economic crop in Taihu Lake region. Heavy nitrogen application in orchard results in great nitrogen loss to drainage ditch, and unbalanced carbon nitrogen ratio. Therefore, carbon might be an important limiting factor for sediment nitrification and denitrification. A soil incubation experiment controlled by the acetylene inhibition method was conducted under laboratory conditions to study the denitrification loss and N2O emissions of orchard drainage ditch soil. We designed five carbon input levels of 0, 5, 25, 50 and 100 mg·L-1, which were noted as C0, C1, C2, C3 and C4, respectively, meanwhile there was 5 mg·L-1 net nitrogen input in the form of KNO3 in each treatment. The results showed that carbon inputs could stimulate both denitrification rates (DN) and N2O emission rates. Carbon and nitrogen ratio had a significant effect on N2O emission rates and denitrification loss rates (P<0.05). When the carbon and nitrogen ratio was 10:1, total cumulative denitrification losses and N2O emissions were both highest (319.26 μg·kg-1 and 6.20 μg·kg-1, respectively) among the treatments, which accounted for 1.28% and 0.02% of net nitrogen input, respectively. This result indicated that the carbon and nitrogen ratio of 10:1 was most favorable for N2O emissions and denitrification process in sediments. |
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