Environmental problems of N fertilisation

High chemical inputs of nutrients have an environmental cost affecting biodiversity, air and water quality, and the global climate:

Although nitrate-related pollution has been reduced slightly in some countries by more targeted application of fertiliser, the overall global trend continues upwards, particularly as the world population grows further. New cereal exporting regions, especially in South America, will suffer disproportionately from the local environmental problems related to high fertiliser inputs over the next decades, if new strategies to reduce fertiliser input while maintaining yield are not available. Also, without any change in agricultural practice, the contribution of N fertilisation to the global problem of climate change is set to continue.

In addition to reducing environmental impact, there are also strong economic imperatives for exploring alternatives to high chemical fertiliser inputs. Over the past 50-60 years, agriculture has benefited from low prices of natural gas and oil, the primary feedstock sources of hydrogen in the Haber-Bosch process for ammonia. Gas is the preferred feedstock in Europe by virtue of being cleaner to process than oil. At the present time, gas and oil prices are rising rapidly due to greater international competition for dwindling resources, and this is feeding through to higher prices for fertiliser. As with other activities dependent on natural gas and oil, interest will increase in strategies to reduce dependence on these non-renewable resources, which in the near future may only be available from politically less stable regions of the world.