A new Soil Association report has been launched at a House of Commons agro-ecology event “The Death of British Farmland?“, calling for farming to become less dependent on manufactured nitrogen fertiliser, and makes the case for a transformation of the current farming system to one that obtains nitrogen from nitrogen-fixing legumes
. New evidence suggests that systems using this type of nitrogen behave differently in terms of nitrogen retention and loss, and a move away from manufactured nitrogen would also help mitigate the climate change impact of farming and guard against the increasing cost of artificial nitrogen. The report “Just say N2O: From manufactured fertiliser to biologically-fixed nitrogen
” is available on the Soil Association website.
‘Too much nitrogen harms the environment and the economy’ was the key message from the recent European Nitrogen Assessment
which reported a study by 200 scientists investigating the unprecedented changes humans have made to the global nitrogen cycle over the last century. Through industrial processes, burning fossil fuels and growing crops, the supply of reactive nitrogen into the environment
has doubled in the last 100 years. The biggest source of this reactive nitrogen is from the industrial manufacture of fertiliser for farming. This energy intensive process produces high levels of nitrous oxide and uses natural gas, a non-renewable fossil fuel, which will get more expensive as supplies get scarce. This will put an upward pressure on fertiliser and food prices and poses a long-term threat to food security.
The Soil Association's report reviews the extent to which organic systems can meet the double challenge
of reducing nitrogen losses and building stores of soil organic nitrogen in order to reduce dependency on manufactured nitrogen. The use of manufactured nitrogen is not allowed in organic systems, so inputs of nitrogen come from nitrogen fixed by legumes, often clover leys as part of a crop rotation that also controls pest and diseases. Scientific evidence shows that the lower nitrogen inputs in organic farming can lead to lower N2O emissions compared to non-organic farms although more research is needed in a number of key areas. The Soil Association is calling on the Government to look at the issue of reducing the dependency on manufactured nitrogen, and increasing efficiency of nitrogen use, as a matter of urgency.