A new £4m project is aiming to provide information on how much nitrous oxide is released by arable crops.
DEFRA had a commitment to reduce greenhouse gas emissions by 2020, ADAS‘s Daniel Kindred explained. “Of the greenhouse gas costs of a tonne of wheat, 70% are thought to be due to nitrogen fertiliser – half in its manufacture and half from nitrous oxide emissions from the soil.
“But those figures are incredibly uncertain, and nitrous oxide emissions could vary from field to field and year to year.”
The project aims to increase understanding of nitrous oxide emissions by measuring them in a range of crops at different nitrogen rates.
Chambers had been placed in plots that allowed researchers to extract air for analysis around 50 times a season, Dr Kindred said. “We should discover how emissions vary per unit of applied N. With nitrate leaching we know it goes up when you put on over the optimum N; does the same principle hold with nitrous oxide?”
If emissions were reduced by applying less nitrogen, it could have implications for bioethanol production, he noted.
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