Improving the efficiency of urea-based fertilization leading to reduction in ammonia emission

A problematic issue in agriculture is the high quantity of ammonia being released resulting in a partial loss of the nitrogen which is contained in urea fertilizers. Alignment with European Union legislation on the regulation of ammonia emission from mineral fertilizers after 2030, urea fertilizers with reduced ammonia emissions by at least 30% will be allowed to remain in use. Currently, laboratory and field tests are carried out to assess the effectiveness of inhibiting nitrogen losses from urea fertilizers. Both urease and nitrification inhibitors are tested. The best results were noticed for the urease inhibitor - NBPT (N-(n-Butyl) thiophosphoric triamide) that can reduce ammonia emissions from urea fertilizers by 30-70% in both laboratory and field tests. The addition of NBPT to the UAN (urea ammonium nitrate solution) fertilizer allowed for the reduction of ammonia emission by 50%. Combining nitrification inhibitors with urease inhibitors may lead to an increase in ammonia emission because they prolong the retention time of ammonium ions in soil, which are the precursors in the process of ammonia emission. In order to meet the imposed requirements under field conditions, in addition factors such as: dose and date of application, method of application, type of soil cultivation, its type and pH and atmospheric conditions should be considered. This review gives an overview of the factors influencing the efficiency of nitrogen use from urea-based fertilizers, taking into account the effectiveness of modified fertilizers (with urease and nitrification inhibitors) in reduction of ammonia emissions.