One of the other major reasons people choose to consume organic food is because they believe organic food production is more sustainable than conventional practices.
“The main differences between organic and conventional food production is that organic farmers are not allowed to use water-soluble nitrogen and phosphorous fertiliser, and there’s environmental impacts associated with those,” said organic farming expert Professor Carlo Leifert from Southern Cross University. The manufacturing of nitrogen fertiliser requires fossil fuels, and is therefore linked to their availability and price. As an example “You need about 1 litre of fuel to make 1 kilogram of fertiliser,” Professor Leifert said.
Professor Leifert said that if you scale that up to a 1,000 hectare crop you need tens of 1,000s of litres of fuel to make the nitrogen fertiliser, which, if it’s ammonium nitrate, can then release huge amounts of carbon dioxide into the atmosphere.
“That’s a massive environmental impact from just one of the components of an agricultural system that organic farmers wouldn’t use.”
While organic farming does better in many areas of environmental impact, its main issue is that because yields are lower, more land is required. With this in mind are there any products that have a larger environmental impact than others? In response Professor Leifert suggests looking at how much fertiliser is applied to crops as a guideline. “So on carrots, the differences in environmental impact are probably smallest because we use the lowest amount of nitrogen fertiliser in conventional farming for those, whereas on something like a brassica [such as broccoli], the impact would probably be in general bigger,” he said.