Aiding reductions to greenhouse gas emissions by maximising nutrient uptake

“To increase the long-term sustainability of our farming systems, reducing our reliance on conventional mineral fertiliser nitrogen (N) and phosphorus (P) is important.”

This according to Dr. Patrick Forrestal, senior research scientist at Teagasc, Soils, Environment and Land Use Department. To tackle this, he is leading the research for Nutri2Cycle, which has demonstrated that farmers can take steps to boost their income, while also protecting the environment.

Patrick commented: “The Nutri2Cycle project brings together 18 partners around Europe to improve the efficiency of nutrients in the soil, along with the capture of carbon.

“We assess and create more efficient and sustainable farm businesses, which optimises the recovery of nutrients and recycling across Europe.”

In Ireland, the project runs until 2022. It examines how manure and leftover materials from dairy product manufacture (such as cheese-making) can be incorporated into farming practices to produce crops. This provides a circular loop for the critical nutrients, while also potentially capturing carbon in the soil.

Recycling is a priority

“Recycling nutrients, by producing food from the bi-products of food production, is a key aspect of a circular economy. This moves us towards higher efficiency and reduced emissions, which will be key to achieving the ambitions of the Green Deal” explained Dr. Forrestal.

Currently in Ireland, a field experiment has been established on a fertile farm in Co. Wicklow. The first year has demonstrated that farmers can save money on fertilisers, while maintaining crop amounts using recycled nutrient sources.

This is a win-win for the environment and the farm business. It was the European Commission which brought together a focus group on nutrient recycling, which formed the core of the Nutri2Cycle consortium.

“The project has also received funding from the EU’s Horizon 2020 research and innovation programme. The EU has played a vital role in facilitating this work,” Dr. Forrestal stated.

Focusing on greenhouse gas emissions

“Agriculture can have a negative environmental impact, as the emissions from animal production [such as meat and milk] can be a significant source of greenhouse gases [GHG], especially ammonia,” stated professor Kevin McDonnell, from University College Dublin (UCD).

“And, with the growing human population, there is an increased demand for meat protein.”

The EU-funded LIFE Farm4More project – co-ordinated by principal investigator Professor McDonnell, alongside colleagues Dr. Joseph Sweeney and Dr. Fionnuala Murphy – aims to reduce the effects of agricultural animal protein production on climate change.

This can be achieved by producing biorefinery protein products (such as plant-based protein) as direct animal protein feed substitutes.

“Ruminant animals [cattle, sheep] can digest and extract amino acids from grass and use these to build proteins.

“However, mono-gastric animals [pig and poultry] cannot digest grass, and so need their amino acids from a different source – usually soybean feed.”

Ongoing Trials

“With Farm4More, we are using grass to make conventional baled silage and allowing it to ferment for 40-60 days. We then press the grass and extract the liquid material. The press cake [solids remaining after liquid] is used as a feed alternative to grass silage.

We add some biochar [which stores carbon] from straw/wood materials, and monitor the intake and emissions from the livestock being fed. The liquid material that we extract from the grass has a high level of sugars and amino acids, and we can use this in pig and poultry diets as a grass substitute for soybean feed product, that is currently being produced outside of the EU and imported into Europe.

55% of the project has been funded by the European Commission, and while trials are ongoing and take time, the research to date is positive.

“It indicates that the animals will have a comparative performance on the press cake, compared with conventional grass silage,” Kevin explains.

“This alternative grass-silage, animal protein production model can significantly improve not only animal protein production efficiency, but GHG emissions for meat and dairy production too.”