| Author(s): |
Carswell, Alison
[1]
;
Shaw, Rory
[2]
;
Hunt, John
[1]
;
Rafael Sanchez-Rodriguez, Antonio
[2, 3]
;
Saunders, Karen
[1]
;
Cotton, Joseph
[2]
;
Hill, Paul W.
[2]
;
Chadwick, Dave R.
[2]
;
Jones, Davey L.
[2]
;
Misselbrook, Tom H.
[1]
Total Authors: 10
|
| Affiliation: | [1] Rothamsted Res, Sustainable Agr Sci, North Wyke, Devon - England
[2] Bangor Univ, Sch Environm Nat Resources & Geog, Bangor, Gwynedd - Wales
[3] Univ Cordoba, Dept Agron, ETSIAM, Cordoba - Spain
Total Affiliations: 3
|
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. (AU) |