ПОЛУЧЕНИЕ ПРОЛОНГИРОВАННЫХ КАРБАМИДОФОРМАЛЬДЕГИДНЫХ УДОБРЕНИЙ И ОЦЕНКА ИХ ВЛИЯНИЯ НА РАЗВИТИЕ СУДАНСКОЙ ТРАВЫ В ВЕГЕТАЦИОННЫХ И ПОЛЕВЫХ ОПЫТАХ

Abstract

The results of studies on the production of prolonged urea-formaldehyde fertilizers (UFFs) in the interaction of carbamide (urea) with formalin («carbamide:formaldehyde» = 1:(0.15÷0.4) mol). It is shown that the rate of dissolution of UFFs granules is significantly lower (10-50 times relative to carbamide). It was found that in the soil, carbamide nitrogen transforms into an alkaline hydrolyzable form within 2 weeks by 30 %, and UFFs nitrogen by only 10 %. It is shown that the value of the «digestibility index» (the main indicator of fertilizer quality) is primarily determined by the ratio of raw materials and decreases uniformly with an increase in the amount of formalin. According to the data of the thermal behavior curves (melting point, loss of mass), it was found that the residual urea content and the amount of the resulting target product, methylenediocarbamide (MDС), in the obtained UFFs samples differ slightly from the calculated values. Despite the insignificant amount of the initial formalin, a small number of other dicarbamide derivatives (monomethylolcarbamide, dimethylolmethylenecarbamide, etc.) are also formed. The number of these compounds is determined not only by the ratio «carbamide:formaldehyde», but also other technological parameters (type of catalyst, pH value, duration of interaction). In order to optimize the composition of UFFs , vegetation and field experiments were conducted (on gray forest soil of experimental fields of Kazan State Agrarian University) with Sudanese grass. The same agrochemical effect of using UFFs in vegetation and field experiments (an increase in green mass to «+ 20-21%» relative to urea) shows that in the field, due to the low rate of dissolution of granules, nitrogen leaching from fertilizers by precipitation is practically absent