Assessing the benefits and wider costs of different N fertilisers for grassland agriculture
Assessing the benefits and wider costs of different N fertilisers for grassland agriculture
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DOI：
10.1080/03650340.2018.1519251
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发表时间：
2019-04-16
影响因子：
2.4
通讯作者：
Misselbrook, Tom H.
中科院分区：
文献类型：
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作者：
Carswell, Alison;Shaw, Rory;Misselbrook, Tom H.
氮肥对于维持不断增长的人口的农业产量至关重要。然而，肥料中过量活性氮的社会、经济和环境影响很少得到评估。本研究在两个草地上评价了硝酸铵（AN）、尿素(U)和抑制尿素（IU；与NPBT） 3种氮肥源的农艺、经济和环境效益。测定各青贮期干物质产量和牧草品质。此外，还测量了NH3-N和N2O-N损失，并用于计算有效氮源成本和外部性成本，这些成本考虑了相关的环境和社会影响。我们发现不同氮源对产量和牧草品质没有影响。然而，在IU处理下，NH3-N排放量显著减少，减少了48-65%。累积N2O排放量无显著差异。考虑到外部性成本，氮、铀和碘的肥料价格分别比原成本提高了1.23-2.36倍、6.51-16.4倍和3.17-4.17倍，将铀从最便宜的氮源转变为最昂贵的氮源。然而，由于氮肥来源之间没有明显的产量差异，除非在销售点将外部性成本纳入化肥价格，否则土地管理者就没有经济动机使用环境和社会上更可接受的选择。
Fertiliser nitrogen (N) is essential for maintaining agronomic outputs for our growing population. However, the societal, economic and environmental impacts of excess reactive N from fertiliser is rarely assessed. Here the agronomic, economic and environmental efficacy of three N-fertiliser sources, ammonium-nitrate (AN), urea (U), and inhibited-urea (IU; with NPBT) were evaluated at two grassland sites. Dry matter yield and herbage quality were measured at each silage-cut. Additionally, NH3-N and N2O-N losses were measured and used to calculate the effective N source cost and externality costs, which account for associated environmental and societal impacts. We found no effect of different N sources on yield or herbage quality. However, NH3-N emissions were significantly reduced under the IU treatment, by 48-65%. No significant differences in cumulative N2O emissions were observed. Incorporating externality costs increased fertiliser prices by 1.23-2.36, 6.51-16.4, and 3.17-4.17 times the original cost, for AN, U and IU, respectively, transforming U from the cheapest, to the most expensive of the N sources examined. However, with no apparent yield differences between N-fertiliser sources there is no economic incentive for the land-manager to use the more environmentally and socially acceptable option, unless externality costs are incorporated into fertiliser prices at the point of sale.