In laboratory experiments, the study was conducted of the size of nitrogen losses due to leaching, as well as the dynamics of ammonium and nitrate nitrogen content in the soil when applying conventional and biomodified urea (BMU), urea-formaldehyde (UF) fertilizer and ammonium nitrate. It was shown that nitrogen was washed out only in the nitrate form from the ammonium nitrate, with losses amounting to 38.7% of the amount applied. The accumulation of nitrate in the soil due to biological oxidation of different forms of urea occurred most intensively on the 7–21 days of the experiment. When UF is applied, the release of ammonium nitrogen occurs extremely slowly, while all the ammonium formed undergoes immediate oxidation to nitrate, as a result of which the content of mineral nitrogen in the soil, when UF is applied, during the 1–7 week of observation was always 1.6–3.0 times lower compared to other fertilizers.
A. A. Zavalin (Wed,) studied this question.