The article is devoted to the study of reducing the technogenic load from high-dose nitrogen pollution of the soil layer by encapsulating granules of nitrogen fertilizers in slowly soluble phosphate-containing membranes. The process of dissolving and washing out of the primordial soil layer of the nutrients from urea, encapsulated by superphosphate shells in soil columns, was studied according to agrochemical techniques. The purpose of the work is to determine the parameters of the investigated process, based on which the previously developed physical model of soil washing of moving nitrogen forms, based on experimental data. The process of changing the loss of nitrogen from the soil when using different types of fertilizers depending on the amount of washing was studied by simulation. Mathematically, the process is described in general terms as a linear differential equation of the first order in partial derivatives. The solution of the equation under the initial and boundary conditions allowed to calculate the parameters of the model describing the nature of changes in the losses of nitrogen from the soil column. Comparison of calculated and experimental data showed a coincidence of values with a correlation coefficient above 0.96 for investigated nitrogen fertilizers with different composition of the phosphate-containing coating.

method consists in the agglomeration of ground rock phosphate with the aid of plasticizer on the base of the compounds of potassium at humidity of the charge not higher than 12 %. The advantages of the designed technology consist in the direct application of phosphorites without their additional crushing, in the use of the raw material that contains potassium as the plasticizer, in the possibility to refrain from treating the obtained fertilizer with preparations-loosening materials. The phosphorus and potassium fertilizers of the NPK=0:13:13 and 0:17:5 types are a certain alternative for ammoniated superphosphate that make it possible to decrease the deficit in the need of agrarians for a basic fertilizer. The availability of potassium and magnesium in this fertilizer compensates for the costs, associated with the fact that 1 t of ammoniated superphosphate by phosphorus is equivalent to 1,42 t of this fertilizer. The given types of fertilizer are intended for the application in farm, forestry and home gardens in all types of soils and for all agricultural crops.

The application of nitrogen fertilizers allows increasing crop yields and partially increase the natural soil fertility. They have a negative influence on the environment due to the significant release of nitrogen. Hence, the technology for decreasing the N-release is proposed in this work. Obtaining of complex organo-mineral NPK fertilizers by encapsulating a carbamide granule with a phosphate-potassium shell with humates is the main aim of this work. The main tasks of this shell is slow release of the nitrogen and phosphate nutrients from the granules into the soil following the agrochemical needs of plants and prevention of soil pollution. The powdered components agglomeration of phosphate and potassium fertilizers with a small amount of liquid phase (plasticizer) allows forming a phosphate-containing coating on a carbamide core by means of the semi-dry method. This innovation allows organizing the production of such a product at the average enterprise with less capital investment. Carbamide prills, phosphate-glauconite concentrate, calcium and potassium ballast humate, and "Avatar" trace-element chelate complex were used in experimental studies. A preliminary assessment of the market prospects for such an innovation shows a high level of market attractiveness for all market participants: producers, consumers, and society.

The structure of carbamide granules, which are encapsulated with an organic shell, is studied in this article. A schematic diagram of an experimental setup for producing organo-mineral fertilizers with a nanoporous shell is proposed. The use of a disk (pan) granulator to encapsulate mineral fertilizers with an organic nanoporous shell has been substantiated. The features of the structure of nanopores that allow to obtain an effective dissolution process of the shell and granule in the soil are presented. Nanoporous structure of the shell is uniform over the entire surface of the shell and occupies from 65 to 75% for different samples. The thickness of the shell in the different parts of the granule is uneven, which requires additional study and correction of the technological parameters of the process. The morphology of the shell's porous structure: rectilinear and curved nanopores, the depth of which ranges from 0.1 to 0.2 of the shell thickness. The pores in shell create a developed structure throughout the entire thickness of the shell, connecting with each other at different depths (thicknesses) of the shell. On the shell surface there is a certain amount of "mechanical" pores, which probably formed during the drying of the sample; the presence of such pores leads to the need to revise the thermodynamic characteristics of the drying process. The elemental composition of the granule core and shell has been studied in order to predict the process of penetration of shell elements into the core within the chosen encapsulation technology. The obtained results allow to improve the technology of obtaining encapsulated fertilizers in pan granulators. Based on the obtained data, it seems possible to improve the algorithm for constructive calculation of the pan granulator.

Research to obtain a long-acting encapsulated fertilizer has been carried out. The performed physicochemical studies confirmed the production of a high-quality phosphate-containing shell on the carbamide prill surface. Solubility of proposed samples were analyzed. The effectiveness of the developed compositions of the encapsulated fertilizer shell was determined. Studies in soil columns were carried out to assess nitrogen leaching. The method of scanning microscopy with elemental microanalysis was used to study the quantitative and qualitative characteristics of the shell and the interface between the outer phosphate layer of the coating and the surface of the urea prill. It is shown that the presence of deep tortuous nanopores in the structure of the phosphate-containing coating allows the penetration of soil moisture into the granule and the successive dissolution of the organic part of the shell and the nitrogen core of the encapsulated granule.