In 2011, a comprehensive trial was carried out to test the efficacy of a urease inhibitor, applied in both a granular application and also as FPA (Fine Particle Application).
The trial was done using the following applications, referenced by a control.
- Granular Urea
- Granular Urea with NBPT (Urease Inhibitor)
- FPA Urea
- FPA Urea with NBPT (Urease Inhibitor)
This summary condenses the scientific paper titled “Urease inhibitor reduces N losses and improves plantbioavailability of urea applied in fine particle and granular forms under field conditions” The original research was a collaboration between University of Canterbury, Massey University and Ballance Agri Nutrients.
THE RESEARCH
Urea was applied in 4 different forms. Firstly, normal prilled urea, fine particle urea then both prilled and fine particle with a urease inhibitor (tradename Agrotain). The researchers used a measurement tool called a Lysimeter which enabled them to measure all liquids leaching through the soil sample, and also measure all Gaseous emissions. They then measured Herbage DM (dry matter) at day 21, 42 and 63.
THE RESULTS
Applying urea in Fine Particle (dissolved) form significantly increased nitrogen response efficiency. (measured in kg’s of DM produced per kg of Nitrogen applied)
- Urea Granular = 10 kg DM / kg of applied N
- Urea Granular + Agrotain = 16 kg DM / kg of applied N
- Urea Fine Particle = 19 kg DM / kg of applied N
- Urea Fine Particle + Agrotain = 23 kg DM / kg of applied N
Nitrate leaching events (rainfall) occurred three times during the 63 day trial. Urea applied in Fine Particle form significantly reduced nitrate leaching. (measured as a percentage of the total applied N)
- Urea Granular = 2.1 % of applied N
- Urea Granular + Agrotain = 0.78% of applied N
- Urea Fine Particle = 0.92% of applied N
- Urea Fine Particle + Agrotain = 0.04% of applied N
SUMMARY
We note that the biggest efficiency was gained by using urea as a fine particle application in comparison to a granular application, not including any NBPT.
NRE = 47% increase in DM production with FPA urea compared to granular urea
Leaching = 56% reduction in leaching with FPA urea compared to granular urea
NOTE: This research was summarised by Metalform (Dannevirke) Ltd. Please see the following link for the full research paper; http://www.sciencedirect.com/science/article/pii/S0167880911002866