Synthetic nitrogen fertiliser has fuelled the expansion and industrialisation of dairy farming in New Zealand. Since 1990, dairy cow numbers have more than doubled and the use of synthetic nitrogen fertiliser increased seven-fold.
According to the OECD, NZ has had the highest percentage increase in synthetic nitrogen fertiliser use out of all of the OECD countries since 1990.
Farmers spread it onto farmland in vast quantities because in the short term it is an easy way to make grass and other crops grow fast.
Synthetic nitrogen fertiliser is a product that is created in factories out of ‘natural’ (fossil fuel) gas. Using this gas and a chemical process these factories take nitrogen out of the atmosphere and convert it into the form plants can use.
Synthetic nitrogen fertiliser is most often sold as ‘urea’ but it’s also mixed up with other fertiliser products and sold under various brand names. In New Zealand it is sold by two companies; Ravensdown and Ballance, who sell 98% of all the fertilisers used in NZ. Industrial dairying is the biggest user by far, using 70% of all the urea in NZ.