Farming must show it is on target to reduce carbon emissions by 10% by 2020 or risk having mitigation measures imposed by government, Yara‘s Mark Tucker warned growers at a Syngenta vegetable crops open day.

The government’s low carbon transition plan formulated in July 2009 targeted a 10% reduction totalling around 3m tonnes of carbon dioxide equivalent greenhouse gas emissions a year from agriculture by the end of this decade, he explained.

“DEFRA will look at how we’re doing from next year, and if it is not enough, it could intervene with its own regulatory measures.”

There were two big hotspots for emissions in the carbon footprint of wheat, he said. “One is the nitrous oxide associated with growing the crop, the other is the nitrous oxide produced during fertiliser production.”

Nitrous oxide had about 300 times the greenhouse gas value of carbon dioxide, so was particularly important to cut, he noted.

Yara had invested about £20m into research to cut nitrous oxide emissions made during the production of fertiliser in the past 10 years. “And we’ve developed abatement technology that removes 90% of the greenhouse gas emissions during manufacture. All Yara’s factories had that technology by the end of 2009.”

It meant choice of fertiliser could have a real impact on cutting greenhouse gas emissions in wheat and other crops, including vegetables, he said.

The other hotspot – nitrous oxide released from soils during the cropping season – would take longer to solve, however, as there was little knowledge of what influenced that process. A DEFRA-funded LINK project was investigating that issue currently, he noted.

Growers should also be looking at increasing the efficiency of nitrogen use in crops, he added. “It has improved as we have improved our agronomy. In 1987, nitrogen use efficiency was 35%, now it is 60-70%, and nitrous oxide emissions over the same period have dropped by 40% in Europe.”

Further efficiency improvements could be made, however, by greater use of soil analysis and in the vegetable sector, Yara was also trialling its N Sensor technology for use in carrots and onions, which would help increase efficiency, he said.