施氮及添加硝化抑制剂对苜蓿草地N2O排放的影响  

Effects of nitrogen application and nitrification inhibitor addition on N2O emissions in Medicago sativa L. grassland

作　　者：倪红 杨宪龙 王刚 来兴发 邓建强[1] 沈禹颖[1] NI Hong;YANG Xianlong;WANG Gang;LAI Xingfa;DENG Jianqiang;SHEN Yuying(College of Pastoral Agriculture Science and Technology,Lanzhou University/State Key Laboratory of Grassland Agro-ecosystems,Lanzhou University,Lanzhou 730020,China)

机构地区：[1]兰州大学草地农业科技学院/兰州大学草地农业系统国家重点实验室

出　　处：《中国生态农业学报（中英文）》2020年第3期317-327,共11页Chinese Journal of Eco-Agriculture

基　　金：国家自然科学基金项目(31872416);教育部长江学者和创新团队项目(IRT17R50);国家牧草产业技术体系(CARS-34)资助~~

摘　　要：摘 要: 为探究旱作紫花苜蓿(Medicago sativa L.)栽培草地氧化亚氮(N2O)排放对施氮水平及添加硝化抑制剂 的响应特征, 采用传统静态箱法研究了不同施氮水平[0 kg(N)·hm 2(N0)、50 kg(N)·hm 2(N50)、100 kg(N)·hm 2(N100)和 150 kg(N)·hm 2(N150)]以及添加硝化抑制剂双氰胺(DCD) 150 kg(N)·hm 2 (N150+DCD)对 陇东苜蓿草地 N2O 排放特征的影响。结果显示, 监测期内 N0、N50、N100 和 N150 处理 N2O 平均排放速率分 别为 3.5 µg·m 2·h 1、4.1 µg·m 2·h 1、5.0 µg·m 2·h 1 和 6.1 µg·m 2·h 1, 随着施氮梯度的增加, N2O 排放速率呈增 加趋势。添加硝化抑制剂 DCD 对 N2O 排放产生明显的抑制作用。与 N150 处理相比, N150+DCD 处理下苜蓿 草地 N2O 平均排放速率下降 50.7%, N2O 累计排放量显著降低 61.6%(P<0.05)。施氮对苜蓿产量没有显著影响, 而 N0、N50、N100 和 N150 处理下单位苜蓿产量 N2O 排放量随氮肥梯度的增加而增加, 各处理分别为 6.5 mg·kg 1、7.8 mg·kg 1、11.3 mg·kg 1 和 12.5 mg·kg 1。N2O 排放受土壤含水量影响深刻, 生长季 N2O 排放通 量与土壤水分呈显著正相关关系(P<0.05), 而与土壤温度无显著相关性(P>0.05)。综上, 旱作紫花苜蓿栽培草 地 N2O 排放通量随施氮水平的增加明显增加, 在相同施氮水平下添加硝化抑制剂DCD能显著抑制N2O 排放。 相关研究结果对于该区域苜蓿草地合理施肥以及 N2O 减排具有一定的实践指导意义。Nitrous oxide(N2O)is undoubtedly one of important greenhouse gases in the atmosphere,which can destroy the ozone layer and aggravate global warming.Agricultural activities,such as fertilizer application,crop straw returning,and biological nitrogen fixation,are the main sources of globally increasing N2O.Therefore,the study of N2O emission characteristics and its impact is of great significance for control and mitigation of environmental pollution.This study investigated the N2O release flux of alfalfa grassland as influenced by nitrogen application and nitrification inhibitor addition,using the static chamber method in Longdong District.The treatments included nitrogen applications of 0(N0),50(N50),100(N100),and 150(N150)kg(N)·hm–2;and nitrification inhibitor(dicyanogen,DCD)addition(N150+DCD).The static chambers were mounted for the estimation of N2O emissions from the enclosed alfalfa chambers for two hours daily,and the radiation,air temperature,soil temperature,and moisture were investigated simultaneously.The results showed that the average N2O emission rates were 3.5,4.1,5.0,and 6.1µg·m–2·h–1 for N0,N50,N100,and N150 during the growing season,respectively.The N2O emission flux was significantly higher in N150 than that in other treatments(P<0.05).Meanwhile,an increasing trend in the N2O emission rate was observed with the increasing nitrogen application gradient.Compared to the N150 treatment,the average N2O emission rate in the N150+DCD treatment decreased by 50.7%,and the cumulative N2O emissions significantly decreased by 61.6%(P<0.05),indicating that the addition of a nitrification inhibitor had a significant inhibitory effect on the N2O emissions.Moreover,the addition of a soil nitrification inhibitor reduced the accumulation of 3 NO-N-in the 0-40 cm soil layer and inhibited nitrification in the soil.The dry matter yield of alfalfa per cutting was not influenced by nitrogen application,as there were no significant differences between the N0 treatment and nitrogen application treatments(P>0.05)

关 键 词：紫花苜蓿 N2O排放通量 氮肥用量 硝化抑制剂 

分 类 号：X511[环境科学与工程—环境工程]