The Soil Association has published 'Just say N2O: From manufactured fertiliser to biologically-fixed nitrogen.' This report reviews the extent to which organic systems can meet the double challenge of reducing nitrogen losses and building stores of soil organic nitrogen so as to reduce dependency on manufactured nitrogen.
It argues that scientific evidence shows that the lower nitrogen inputs in organic farming can lead to lower N2O emissions compared to non-organic farms but that, given the imperative to reduce our reliance on manufactured nitrogen and improve the efficiency of nitrogen use more research is needed in a number of key areas. These are as follows:
- The Government should investigate the likelihood that legume-based organic systems and those using manufactured nitrogen behave differently in terms of nitrogen cycling, retention and loss. There is an urgent need to understand the consequence of this for long-term soil fertility, reducing GHG emissions, storing carbon in soil and reducing our dependence on manufactured fertilisers.
- The Government should fund research that looks in detail at N2O emissions from organic systems to bring scientific understanding to the same level as will be provided by the Government’s ‘InvenN2Ory’ project for non-organic farming practices. This would contribute to the ‘futureproofing’ of the UK GHG Inventory and ensure that emissions from organic systems are represented using accurate emissions factors.
- There is an urgent need for further research into best practice for organic farms and other agro-ecological farming systems on how N2O emissions and other nitrogen losses can be minimised. Research is also needed into innovative methods already being trialled on organic farms. For example, alternatives to ploughing in legumes such as crops direct drilled into legumes, the use of perennially based cropping systems and agroforestry.
- The European Nitrogen Assessment called for a lowering of the human consumption of animal protein as a way of also tackling nitrogen excesses. Research into the impact of nitrogen use and pollution as a consequence of a shift in diets in the UK to lower consumption of meat and dairy products, especially from animals fed on grain rather than grass, should be commissioned to accompany existing evidence of the climate change and health benefits.
- Using clover on grassland to fix new nitrogen, rather than manufactured nitrogen is a practice that can be readily adopted by non-organic farmers. The use of winter cover crops by those growing spring sown crops should also be encouraged. The Government should provide financial incentives to help farmers implement such measures, and these could be included as part of the ‘greening’ of Pillar 1 of the Common Agriculture Policy.
You can download the report here.