Ammonia emissions from urea and manure slurry reduced using Polysulphate

Agriculture is the main source of ammonia emissions to the atmosphere is agriculture, accounting for over 80% of emissions (Wyer, K. et al, 2022).  Mahmud, K. et al (2021) estimates global ammonia emissions of 45 Tg/year, although other researchers have proposed even higher values.  This pathway of nitrogen losses does not only represent a direct economic loss to farmers, but it also contributes significantly to eutrophication and acidification of natural ecosystems, as well as being a threat to human health due to formation of fine particles (PM2.5) that can cause lung diseases (Sommer, S. et al 2019).

Significant attention has been given to the development of solutions to reduce volatilisation from inorganic fertilisers, however less than 20% of all ammonia emitted from agriculture is linked to these products. The main source of ammonia volatilisation is animal production and the manure it produces.  The losses are at all stages of production, such as stables and poultry houses, manure storage and manure application.  For this reason, the only way to make a real impact in reducing ammonia emissions will be to create solutions aimed at animal manure related emissions. ICL has found that Polysulphate can provide a natural mitigation of the ammonia problem since it can help reduce its volatilisation from both mineral nitrogen and manure.

A laboratory study was conducted to compare emissions from conventional urea with those from granulated Polysulphate with urea (using different ratios). For this work, four soils were used with contrasting physical and chemical characteristics. Over a period of 14 days the ammonia emissions from the Polysulphate with urea were significantly lower than those from urea alone on all soils, but at different levels.  On average a reduction of ammonia emissions of 25-35% was observed.