Crop Nutrition Key to Reducing Emissions
03.02.2025
Andrew Clune has worked in agriculture all his life. In the mid-90s he studied in New South Wales, Australia before he headed to the UK and embarked on a career in agriculture. Today he is a Business Development Manager for BASF and recently attended the YEN Conference as a session chair and panellist.
Here are his thoughts:
"While it is difficult for me, as an Australian, to admit it, British agriculture is among the best in the world. We’ve some of the most efficient producers, growing some of the highest quality foods."
Our industry hasn’t become a world-leader by accident. Generations of farmers have dedicated their entire lives to improving their understanding and have been generous in sharing their knowledge and experience.
The Yield Enhancement Network (YEN) is a great example of how, our generation is building on the wisdom of our predecessors. It has unique approach of driving and challenging the arable sector with the rigour of field-based science and sportsmanship competition.
One of the newest members of the YEN ‘family’ is YEN Zero. Now in its fourth year, this competition seeks to reduce crop’s greenhouse gas emissions (GHGs) while increasing productivity.
We’ve already learnt so much from the 88 growers and the 609 crops that have been entered in YEN Zero, as ADAS’ Senior Research Consultant, Christina Baxter revealed at the conference.
From YEN Zero we now know that 65% of the total carbon footprint of a feed wheat crop comes from crop nutrition. It’s also a significant proportion of the emissions associated with oilseed rape (52%) and to a lesser extent, beans (20%).
With figures in hand, it’s abundantly clear where we need to focus our attention if we’re to achieve Net Zero in the arable sector. Fortunately, when it comes to crop nutrition, we’ve already got some of the tools in the toolbox (or on order!) and are well on our way.
For example, we’ve been looking at nitrogen use efficiency (NUE) in crops and optimising applications for decades. In 1961, it’s estimated that NUE was 28.36%, today the UK’s NUE averages 66.69%. We’ve made significant strides in ensuring that those fertilisers we apply are used by crops.
What’s new is that leading manufacturers have been seeking more sustainable ways of producing artificial fertiliser. There are new options on the horizon. ‘Green Ammonia’ uses electrolysis powered by renewable energy to do the Haber Bosch process, bringing its carbon footprint down. While ‘Blue Ammonia’, halves emissions by capturing and sequestering the CO2 that’s produced in the production of UAN and combining it with the ammonium sulphate recovered from waste streams, such as wastewater and sewage.
Alongside the quest for more sustainable sources of nitrogen, the industry is on a mission to reduce nitrification of fertilisers once they’ve been applied. Nitrous oxide has a global warming potential nearly 300 times that of carbon dioxide, so it is an area well worth our time, money and effort. Through the YEN NET ZERO we know that using nitrification inhibitors can decrease the total carbon footprint of a feed wheat crop by 14%.
Then there are urease inhibitors, these reduce ammonia emissions from urea and urea ammonium nitrate (UAN). Figures from the GHG inventory based on trials in the UK show they can improve NUE and reduce GHG from crops by up to 9%.
For me, they are a key area. As well as having a GHG effect, ammonia emissions also contribute to ozone depletion, acid rain, eutrophication and atmospheric pollution, and with agriculture accounting for 88% of all UK ammonia emissions, I feel we have to take responsibility.
The government has been charged with taking around 80t of ammonia from the atmosphere each year and is proactively testing for it. They are also matching fertiliser sales with inhibitor sales. It’s just not a box ticking exercise for Red Tractor.
The consequences of ignoring the guidelines and applying urea without an inhibitor after 1st April, are potentially significant for the whole industry. The preceding government leaving the door wide open for them to reconsider the options that were on table when they did the first round of consultations and that includes banning the use of urea altogether.
On a positive note, urease inhibitors (UIs) have been shown to have benefits beyond the environment. Our product, Limus, for example, with its two actives NBPT and NPPT, has been proven to reduce ammonia losses by 98%, increasing NUE on-farm and delivering a 4% increase in yields. Financially, UIs are not a cost but an investment.
At a time when farmers are feeling that food production is counter to sustainability, it was comforting to hear YEN’s discovery that increasing yields is important. In short, higher yields are associated with lower emissions. But that doesn’t necessarily mean higher inputs - more widely across YEN we’ve clearly seen that it is the right intervention, in the right place and at the right time that leads to high yields.
Or as the ADAS Head of Crop Performance and YEN Director, Roger Sylvester-Bradley, put it: plan, check, adjust and review.
Photos from Alan Bennett
