The Role of Urea Types in Minimizing Leaching Loss to Maximizing Its Use Efficiency

The research aimed to investigate the behavior of nitrogen (N) when different types of urea fertilizers are used in Alfisol. Traditional chemical fertilizers have a low N use efficiency, around 30 to 35 percent, posing a significant challenge for improvement. This study sought to assess the effectiveness of urea coated with various materials compared to regular urea and prilled urea, focusing on how they affect N release dynamics and leaching losses. Results showed that urea coated with certain materials, such as CSPC @3% and neem-coated urea, resulted in lower levels of NH4+-N in the leachate compared to conventional and prilled urea. Specifically, CSPC @3% exhibited a gradual release pattern, with NH4+-N levels decreasing from 55.00 to 54.00 µg between the 0th and 50th day of leachate collection (DLC). Moreover, NO3--N levels were lowest in CSPC @3%, ranging from 17.71 to 31.00 µg during the same DLC period. These findings suggest that uncoated urea undergoes hydrolysis upon application, leading to conversion into various forms of nitrogen, including available, ammonical and nitrate. However, nitrate despite being present in smaller quantities is particularly susceptible to leaching losses. Therefore, the use of coated urea formulations like CSPC @3% and neem-coated urea can help minimize such losses, thus enhancing nitrogen use efficiency.