Scientists urge gardeners to ditch nitrogen fertilisers

GARDENERS should stop using nitrogen fertilisers, scientists have said, as greenhouse gas emissions are rising far faster than carbon dioxide.

A study by the University of East Anglia, published in Nature magazine, found that the widespread use of nitrogen fertilisers in agriculture means the release of nitrous oxide is far higher each year than previously thought.

Findings show nitrous oxide emissions are rising faster than any scenario developed by the Intergovernmental Panel on Climate Change and are consistent with greenhouse gas scenarios that lead to global mean temperature increases well above 3C from pre-industrial levels. The Paris Agreement aims to limit warming to less than 2C.

Dr Parvadha Suntharalingam, the study’s lead author, said: “This study presents the most comprehensive and detailed picture to date, of nitrous oxide emissions and their impact on climate.

“This new analysis identifies the factors driving the steadily increasing atmospheric levels of nitrous oxide, and highlights the urgent need to develop effective mitigation strategies if we are to limit global warming and meet climate goals.”

While emissions of other greenhouse gases are being curbed, nitrous oxide has risen 20 per cent from pre-industrial levels with the fastest growth observed in the past 50 years due to emissions from human activities.

Human-induced emissions, which are dominated by nitrogen additions to croplands, increased by 30 per cent over the past four decades. The release of nitrous oxide into the atmosphere is mainly from agriculture, but gardeners often use heavy- duty fertilisers for lawns and cruciferous vegetables.

Guy Barter, chief horticulturist at the Royal Horticultural Society, recommended that compost be used instead.

He told The Daily Telegraph: “Typically, you use nitrogen fertilisers to feed lawns and some vegetables such as cabbages and beetroot. The principles of good gardening is recycling, like composting things in your compost bin, there’s no better fertiliser than compost. Nothing’s perfect, you sometimes get nitrous oxide released from organic manure but there’s much less of a risk.”