04-05-2025
Researcher lauds potential economic benefits of duckweed for Ireland
According to University College Cork (UCC) professor, Marcel Jansen, a small free-flowing aquatic plant – duckweed – has significant economic and environmental potential for the agriculture industry which lies untapped.
While the perennial plant has been used as an important source of protein in Asian cultures for centuries, it remains a relatively new concept in the western world, despite its latent nutritional benefits.
For Prof. Jansen, the benefits of duckweed are twofold – its positive ecological impact through its ability to recycle nutrient waste and, in turn, enhance water quality; and, secondly its potential as feed for livestock.
Duckweed can consume vast quantities of nitrogen and phosphorus from the environment and can therefore go a long way in countering nutrient leakage in waterways from agriculture.
This in turn lowers the agricultural sector's environmental footprint without compromising productivity.
Duckweed
Prof. Jansen said that the plant can also outcompete the growth of algae in loughs and other slow-moving waterways, mitigating the biodiversity challenges posed by such colonies of algae, provided it is harvested in a timely fashion.
The researcher has conducted and published studies on the plant's capacity to grow and detoxify runoff from the dairy industry, to great avail.
In collaboration with colleagues from UCC and the Technical University of the Shannon (TUS), the Dutch-born academic has conducted trials in a former Bord na Mona bog in Mount Lucas, Co. Offaly, whereby 30t of duckweed were grown on a hectare of land, thus proving its ability thrive in natural conditions in Ireland.
Prof. Marcel Jansen
Prof. Jansen explained: 'Why that is important is that it shows in the Irish climate, under natural conditions, duckweed is a very realistic crop.
'What you do in the lab is not that relevant, it's real life examples that count step because on that basis, you can start talking to farmers.'
The researcher has ramped up efforts to engage with the farmer community in recent times, and is currently collaborating with a farmer in Clonmel, Co. Tipperary to innoculate the plant on a pond on the farm.
However, the real obstacle impeding the realisation of duckweed's innate potential lies in the current absence of economic incentives for production within the Irish and European market.
With a 30% protein content and an ability to grow rapidly in an Irish context – even in challenging circumstances – Prof. Jansen claimed that duckweed would make for a quality ingredient for livestock feed and a natural substitute for soy.
According to the researcher, an uptake in the cultivation of duckweed for feed production will depend upon demand from feed companies, which has yet to materialise, although he asserted that this will only be a matter of time.
'Farmers know about duckweed, there's actually very good awareness about its potential, but the big thing is they need to make money out of it.
'They need to see a form of income not for just one year, but for a number of years and that will only happen if the demand is there.
'The feed companies are looking into it, but if they are going to invest in a new feed source to replace soy, they want to have a minimum couple of years of steady supply.
Prof. Jansen said he is hopeful this situation will soon change.
'We are working with one of the big feed companies, I'm not mentioning the name at the moment, but they are actively trialling duckweed as a replacement of soy. That's on an experimental basis, but that should lead hopefully to demand.
'That shows you how far we have come and the number of possibilities there are with duckweed,' he added.
Prof. Jansen is currently looking at two feed sources in which duckweed would be particularly apt at replacing soy as a primary ingredient – pig feed and fish food.
'If you think about Ireland, the bulk of our soy goes to pig feed, that's one of the biggest targets for us. The second is fish food because roughly half of it is made of fish. So boats are going out to catch fish to feed other fish, which is madness,' Prof. Jansen explained.
'There has been some very good experiments done that show the possibility of replacing part of fish food with duckweed.
'The interest is there, the awareness is there. It's now about achieving the economic benefits of duckweed,'
