Assessment of gaseous ammonia losses when using urea and urea-formaldehyde fertilizers

The aim of the study was to investigate the size of gaseous ammonia losses during surface application of standard urea and new forms of urea-formaldehyde fertilizers under conditions of a model experiment. Laboratory experiments with composting were carried out in 2024 on sod-podzolic medium loamy soil and leached medium-deep heavy loamy chernozem with surface application of standard urea and experimental forms of urea-formaldehyde fertilizers (UF 12-1, UF 13-1 and UF 14-1), differing in the content of total nitrogen and its individual fractions. Noticeable gaseous ammonia losses occurred on the third day of composting and reached a maximum value on the 28th day. At the same time, the most intense nitrogen losses occurred on sod-podzolic soil. When urea was introduced, ammonia release increased from 0.31 mg of nitrogen per vessel on the 3rd day of observation to 12.06 mg/vessel on the 28th day. On leached chernozem, ammonia urea losses were significantly lower compared to sod-podzolic soil and increased from 0.47 to 2.19 mg/vessel on the 3rd and 28th days, respectively. After four weeks of composting on sod-podzolic soil, ammonia nitrogen losses amounted to 18.1 % of the amount introduced, and on leached chernozem, losses were almost 6 times lower and amounted to 3.3 %. The release of ammonia in the variants with the introduction of experimental forms of UF was insignificant and did not exceed 1.2 % on sod-podzolic soil and 0.7 % on chernozem over 28 days of observation. No significant differences in the amount of released ammonia from the composition of different forms of UF were found.

nitrogen, urea, urea-formaldehyde fertilizers, sod-podzolic soil, leached chernozem, composting, ammonia losses