Agriculture & Food, Volume 9, 2021

Rezumat: A method is proposed for obtaining prolonged nitrogen-magnesium fertilizers by «cementing» industrial nitrogen fertilizers ( urea – Ur, ammonium nitrate – АN) with some magnesium hydroxide salts [nMg(OН)2·Mg(NO3)2·mН2О, nMg(OН)2·MgSO4·mН2О – also known as «Sorel's cement» (SC)]. The components of «Sorel cement» contain the main elements of plant nutrition (N, Mg, S), the resulting complex N(Mg)- and N(MgS) fertilizers are alkaline [due to the presence of Mg(OН)2], which contributes to the neutralization of soil acidity. The proposed method allows you to obtain a granular urea-ammonia mixture (UAM) instead of its solution. The main criteria for the quality of prolonged N(Mg)- and N(MgS)-fertilizers are the ratio «MgO:UAM»; «SC:UAM»; «MgO:N». The total content of  N(Mg)  2030 % with the optimal ratio «MgО:N» = (0,20,6) mass. It has been established that the strength of granules of N(Mg)- and N(MgS)-fertilizers is much higher (compared to granules of urea), and the dissolution rate is 10-50 times less. The pot experiments show that the new fertilizer contribute to a substantial increase in weight of wheat (at 26-49 %) and the yield of green mass Sudan grass (at 28-35%).