| 摘要: |
| 【目的】研究黄土高原旱地麦田土壤N2O排放对长期不同氮肥用量的响应,探明旱地麦田N2O排放规律及其主要影响因素，为该区域旱地麦田氮素管理和N2O减排提供依据。【方法】在2004年10月开始的黄土高原旱地冬小麦氮肥长期田间定位试验(施磷（P2O5）100 kg/hm2)基础上，设置5个氮水平，氮肥（纯N）用量分别为0(N0)、80(N80)、160(N160)、240(N240)、320(N320) kg/hm2，利用静态箱/气相色谱法于2014-2016年连续2年检测不同氮肥水平下麦田N2O的排放特征，并分析了N2O排放通量与土壤NH+4-N、NO-3-N含量及气温的关系。【结果】施用氮肥能显著提高旱地麦田N2O的排放通量，施用氮肥后的50 d内为N2O排放高峰期，N80、N160、N240和N320处理的N2O排放通量最高值分别是对照（36.20 μg/(m2·h）)的2.5，3.2，4.9和6.4倍。小麦进入春季后（施肥后120 d），因气温升高和降雨增加会出现多次N2O排放高峰，而在成熟期（施肥后210 d）N2O排放通量相对较低。2个小麦生长季N80、N160、N240、N320处理的平均N2O总排放量较对照（0.29 kg/hm2）分别增加1.6，2.8，4.3和6.1倍，排放系数为0.47%~0.59%，平均为0.55%。N2O排放通量与土壤NH+4-N、NO-3-N含量和气温呈极显著正相关关系，且N2O总排放量与施氮量呈显著线性关系。【结论】施用氮肥显著增加了黄土高原旱地麦田N2O排放通量及总量，是该区域麦田N2O排放的最主要驱动因子，气温和降水量也会在一定程度上影响N2O排放。 |
| 关键词: 旱地 施氮量 N2O 排放系数 温室气体 |
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| 基金项目:国家自然科学基金青年项目（41201238）；国家重点研发计划项目（2016YFD0200105）；陕西省自然科学基础研究计划青年人才项目(2015JQ4113)；西北农林科技大学博士科研启动基金项目 |
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| Effect of nitrogen fertilizer on N2O emissions from winter wheat field in the Loess Plateau |
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LI Baoyan,QIU Weihong,HUI Xiaoli,et al
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| Abstract: |
| 【Objective】This study investigated the effect of long term nitrogen fertilization on N2O emissions in dryland wheat field on the Loess Plateau and explored the characteristics of N2O emissions and main influencing factors to provide guidance for managing nitrogen fertilization and mitigating N2O emissions.【Method】Based on a long term filed experiment with five N fertilizer application rates (0(N0),80(N80),160(N160),240(N240),320(N320) kg/hm2) and the phosphate fertilizer (P2O5) of 100 kg/hm2 in 2004,N2O emissions from the winter wheat field were measured using astatic chamber gas chromatograph technique during 2014-2016.The relationship of N2O flux with NH+4-N,NO-3-N and temperature was analyzed.【Result】N fertilization significantly increased N2O emissions from the winter wheat field,and N2O flux peaks occurred in first 50 days after N fertilization.The N2O flux peakes of N80,N160,N240 and N320 nitrogen treatments were 2.5,3.2,4.9 and 6.4 times compared to the control (36.20 μg/(m2·h）),respectively.There were several N2O emission peaks due to the increase of temperature and rainfall in the spring (120 d after fertilization), while the flux was relatively low in the wheat mature stage (210 d after fertilization).The mean N2O total emissions of N80,N160,N240 and N320 treatments were 1.6,2.8,4.3 and 6.1 times higher than the control treatment (0.29 kg/hm2),accounting for 0.47%-0.59% of N fertilizer application rates with an average of 0.55%.There were significant positive correlations between N2O flux and NH+4-N,NO-3-N or temperature,and the total N2O emission showed a significantly linear relationship with N fertilizer application rate.【Conclusion】 N fertilizer application significantly increased N2O emission flux and total N2O emissions,and it was the main driving factor in the wheat field.Rainfall and temperature also affected N2O emissions. |
| Key words: dryland nitrogen application rate N2O N2O emission factor greenhouse gas |
