The effect of nitrogen concentration in synthetic cattle urine on nitrous oxide emissions
The effect of nitrogen concentration in synthetic cattle urine on nitrous oxide emissions
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DOI：
10.1016/j.agee.2014.02.020
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发表时间：
2014-04-15
影响因子：
6.6
通讯作者：
Cox, Neil
中科院分区：
文献类型：
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作者：
de Klein, Cecile A. M.;Luo, Jiafa;Cox, Neil
本研究测定了田间条件下人工合成牛尿中N浓度与N2O排放因子(EF3；N2O-N排放量占尿氮施用量的百分比)之间的关系。这一结果将改善对影响尿氮浓度和沉积率的N2O缓解方案的有效性的评估。在2个自由排水土壤和1个排水不良土壤上，采用人工合成尿液，N浓度分别为0、2、4、6、8、10和12g N L(相当于0~1200kgN ha(-1))。对排水不良土壤的研究还包括尿氮浓度为14g N L-1(1400kgN ha-1)。使用静态室方法测量尿液后长达18周的N2O排放量。自由排水土壤的EF3值为尿氮的0.03%~0.34%，排水不良的土壤为0.5%~0.9%。在自由排水土壤上，EF3随施氮量的增加而增加的趋势显著(p<；0.05)，在最低施氮量和最高施氮量之间，EF3增加了3~4倍。在排水不良的土壤上没有发现这种趋势，表明该土壤的N2O排放系数与施氮量无关。这些结果表明，尿氮浓度只在很低的情况下才影响N2O排放因子。因此，我们得出的结论是，减少个别排尿事件中的尿氮浓度的缓解策略，而不是整个农场系统的总体尿氮排泄量，对减少总的直接N2O排放的影响可能有限。(C)2014爱思唯尔B.V.保留所有权利。
This study determined a relationship between N concentration in synthetic cattle urine and the nitrous oxide (N2O) emission factor (EF3; N2O-N emitted as % of urine N applied) under field conditions. The results will improve the assessment of the efficacy of N2O mitigation options that affect urinary N concentration and deposition rates. Field studies on two free draining soils and one poorly draining soil were conducted using synthetic urine with N concentrations of 0, 2, 4, 6, 8, 10 and 12 g N L-1 (equivalent to application rates of 0 to 1200 kg N ha(-1)). The study on the poorly draining soil also included a urine N concentration of 14 g N L-1 (1400 kg N ha-1). N2O emissions were measured for up to 18 weeks after urine application using a static chamber methodology. The EF3 values ranged from 0.03 to 0.34% of urine N applied on the free draining soils and from 0.5 to 0.9% on the poorly draining soil. There was a statistically significant (p < 0.05) trend of increasing EF3 with increasing N application rate on the free-draining soils, with EF3 increasing 3- to 4-fold between the lowest and highest N rate. No such trend was found on the poorly draining soil, indicating that for this soil the N2O emission factor was independent of the N application rate. These results suggest that the urine N concentration only affected the N2O emission factor when values were very low. We therefore conclude that mitigation strategies which reduce the urine N concentration in individual urination events, but not the overall total amount of urine N excreted over the whole farm system, may have limited impact on reducing total direct N2O emissions. (C) 2014 Elsevier B.V. All rights reserved.