Research into Ammonia Volatilisation and Nitrate Leaching following Nitrogen Fertiliser Application

A study using Nutrisphere-N® conducted on a Coarse-Textured Soil

The use of urea-ammonium nitrate solution (UAN) is common as a nitrogen fertiliser source in agriculture due to its affordability. However, the risk of nitrogen loss through ammonia (NH3) volatilisation and nitrate (NO3-) leaching is a concern with urea-based fertilisers. Chemical compounds such as nitrapyrin and maleic-itaconic acid copolymer can be added to inhibit transformations of nitrogen and reduce nitrogen loss. Nitrapyrin is considered an effective nitrification inhibitor, while maleic-itaconic acid copolymer is claimed to act as a urease inhibitor. However, the effectiveness of inhibitors can vary depending on environmental factors.

This research explores the effects of different nitrogen sources on ammonia (NH3) volatilisation and nitrate (NO3-) leaching in a coarse-textured soil under different environmental factors. The study examines the impact of various fertilisers including polymer-coated dry urea (PCU), and urea-ammonium nitrate solution (UAN) with various additives on nitrogen loss through ammonia (NH3) volatilisation and nitrate (NO3-) leaching. One UAN additive (UAN-NS) can be seen with Nutrisphere-N (maleic-itaconic acid copolymer) which acts as an inhibitor of urea hydrolysis and nitrification and may limit ammonia (NH3) volatilization and nitrate (NO3-) leaching and improve plant nitrogen uptake.

The laboratory study simulated rainfall events to mimic dry and wet conditions observed in the field. UAN-NS was shown in wet conditions to have had low ammonia (NH3) loss while also showing a reduced amount of nitrate (NO3-) leaching compared to UAN. Research also showed that, over a longer period of time under dry conditions, the UAN-NS treatment also significantly reduced ammonia (NH3) loss compared to UAN and other additive treatments. UAN-NS was also shown to have a significantly lower leaching loss comapred to the UAN treatment.

Compared with the PCU treatment, UAN-NS was shown to have a higher total fertiliser nitrogen recovery within a range of 76 to 87%, while the PCU treatment had a total fertiliser nitrogen recovery range of 64% to 71%. Total measured fertiliser nitrogen losses for UAN-NS were also shown to be lower in both Dry (11.2%) and Wet (52.5%) conditions compared to UAN (16.1% Dry, 65% Wet), while also significantly lower compared to the other UAN additive in dry conditions (18.7% Dry)

Overall, from this research, the UAN additive Nutrisphere-N was seen to perform well under this study with this treatment limiting nitrogen loss compared to UAN on its own as well as showing other positive results with reduced nitrate leaching and ammonia loss. Further research can explore its performance under different soil and climatic conditions to see how it will perform.

For more information on this research, click the link below:

https://www.researchgate.net/publication/272999979_A_Laboratory_Evaluation_of_Ammonia_Volatilization_and_Nitrate_Leaching_following_Nitrogen_Fertilizer_Application_on_a_Coarse-Textured_Soil