Report reveals 'untapped potential' of sustainable fertilisers

Switching to alternative varieties will save farmers money and naturally enrich soil on their lands

Switching from traditional fertilisers to alternative varieties not only saves farmers money but will naturally enrich the soil on their lands, a report has revealed.

A four-year study, carried out under the lead of scientists from a Cork university and a top Dutch research facility, has found significant benefits for farmers who replace traditional mineral fertilisers with sustainable alternatives such as compost, digestate (the substance left over from anaerobic digestion processes), household waste, grass cuttings, or animal slurry.

Studies have shown that digestate, for example, is an excellent fertiliser containing all the nutrients and micronutrients necessary for modern farming, including nitrogen, phosphorus, and potassium.

However, farmers currently predominantly use mineral fertilisers that are a limited resource and can be energy-intensive to produce.

The study, which sets out to assess the demand for recycled fertilisers across North-Western Europe, is being carried out by researchers from the Munster Technological University Cork and the Nutrient Management Institute in the Netherlands, and is scheduled to run until 2022.

The research is taking place as part of the EU-funded

ReNu2 Farm project, which aims to encourage the use of sustainable fertilisers.

“The agriculture sector in Ireland is the largest producer of greenhouse gas emissions of any sector in Ireland,” said Niamh Power, lecturer at the Department of Civil, Structural and Environmental Engineering at MTU Cork.

We need to look at how we can reduce these emissions.

“We found that Irish farmers require less potassium and less phosphorus for their land than their EU counterparts, and that they can therefore get enough from sustainable alternatives which can often be obtained at a reduced cost compared to traditional fertilisers,” she added.

“This is untapped potential. In Ireland, we have a number of anaerobic digestion and compost facilities and farmers can avail of the products at these facilities at a reduced cost.”

Ms Power said that while the research team has not yet fully quantified the potential savings, the team has also discovered that financial benefits are merely one of the advantages for farmers who make the switch to more sustainable varieties.

Recycled fertilisers have additional, naturally beneficial nutrients, and high levels of organic matter which enriches the soil, she said, “so farmers who decide to use these are essentially improving their farmland”.

The report gives insights into crop nutrient demand, current use of organic fertilisers and estimates the potential demand for recycling-derived nutrients.

Researchers have also developed an online interactive map to show regional nutrient demand for the entire Northwest Europe territory. 

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