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  

Denitrification Loss and N_2O Emission from Different Carbon Inputs in Orchard Drains Sediments

作　　者：高雪梅[1] 佘冬立[1,2] 颜晓元[2] 夏永秋[2] 

机构地区：[1]河海大学水利水电学院,南方地区高效灌排与农业水土环境教育部重点实验室,南京210098 [2]中国科学院南京土壤研究所土壤与农业可持续发展国家重点实验室,南京210008

出　　处：《环境科学》2016年第7期2731-2737,共7页Environmental Science

基　　金：国家水体污染控制与治理科技重大专项(2012ZX07101-004);土壤与农业可持续发展国家重点实验室开放基金项目(Y412201423);中央高校基本科研业务费专项(2015B14814);江苏省水利科技项目(2014075)

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C_0、C_1、C_2、C_3、C_4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N_2O的排放量.结果表明,加入碳源使土壤的反硝化速率(DN)和N_2O排放速率均有一定的增加,碳氮比对N_2O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N_2O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N_2O的排放.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 N_2O 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 C_0,C_1,C_2,C_3 and C_4,respectively,meanwhile there was 5mg·L- 1net nitrogen input in the form of KNO_3 in each treatment. The results showed that carbon inputs could stimulate both denitrification rates（ DN） and N_2O emission rates. Carbon and nitrogen ratio had a significant effect on N_2O emission rates and denitrification loss rates（ P〈 0. 05）. When the carbon and nitrogen ratio was 10 ∶ 1,total cumulative denitrification losses and N_2O emissions were both highest（ 319. 26 μg·kg^（-1） and 6. 20 μg·k^（-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 N_2O emissions and denitrification process in sediments.

关 键 词：碳输入 碳氮比 反硝化 N2O排放 累积排放量 

分 类 号：X144[环境科学与工程—环境科学]