Nitrogen from fertiliser can incease climate change.
With scientists linking March’s unseasonably cold weather to melting Artic sea ice, and following on from England’s wettest year on record, the erratic effects of climate change are being felt by British farmers. While snow is not unheard of at Easter, this March is set to be the coldest for 50 years and the conditions have made life difficult for arable and livestock farmers alike. Speaking in the Farmers Guardian, NFU Vice President Adam Quinney acknowledged just how bad the weather has been:
“These are unusual conditions and are totally out of character for the time of year. It has put an extraordinary strain on the industry after what has been a torrid 12 months of extreme weather, compounded by the fact that many farmers’ sheep are lambing at the moment.”
When the snow eventually clears arable farmers will be keen to apply nitrogen fertiliser to catch up on lost crop growth, but the Farm Carbon Cutting Toolkit (FCCT) is suggesting farmers be cautious with the first N top dressing. The high soil moisture levels and slow crop growth present at the moment are likely to cause higher Nitrogen losses from the soil, particularly the powerful greenhouse gas Nitrous Oxide.
Adam Twine, a director of FCCT and mixed farmer in Oxfordshire, said: “Nitrous oxide (N2O) is 300 times more powerful than carbon dioxide as a greenhouse gas. This spring’s conditions are particularly likely to lead to greater than usual losses of Nitrogen from fertilizers applied too early or in quantities greater than the crop can use.”
Plants take up most of their Nitrogen from the soil in the form of nitrates, supplemented by ammonium nitrate fertilizer added to the soil. While most of the Nitrogen will be rapidly taken up by plant growth, some may be leached out of the soil or become denitrified. If there is too much Nitrate for the plants to take up, denitrification and leaching will occur.
“For arable farmers like myself, N2O emissions are the greatest source of GHG from our systems,” said Adam Twine. “Almost half the carbon foot print for a tonne of wheat comes from the use of nitrogen fertilizers: how much care we take in applying them can make a significant difference to that crop’s GHG emissions.”
“Waiting for the soil moisture levels to reduce and matching the rate to what the crop is realistically going to take up in the next two weeks will not only save money from less waste of the fertilizer, it will also improve your carbon footprint – it’s a rare win win!”
It’s also a win-win for reducing farming’s contributions to climate change. If we are to lower the risk of ‘extreme’ weather events becoming the norm with a rapidly changing climate, agriculture along with other sectors needs to take action to reduce our GHG emissions at all opportunities available.
The toolkit section of the FCCT website offers advice to farmers on how best to apply fertiliser while reducing their GHG emissions. The FCCT has a complete toolkit for reducing farm GHG emissions, including its own carbon calculator, all of which is freely available on its website.