THE INFLUENCE OF THE SOIL ON THE ACTIVITY OF THE COMPONENTS OF MIXED MINERAL FERTILIZERS
The research objective was studying the influence of clay soils on the properties of nitrogencontaining, phosphorus-containing and potassiumcontaining mineral fertilizers. The main minerals of clay soils (kaolinite, montmorillonite, illit) contain aluminum oxide which mass fraction in kaolinite, for example, in kaoliniteit it is 39 %. Aluminum oxide influence on the activity of oxygen, nitrogen, phosphorus and potassium in mineral fertilizers was revealed. The research was carried out by the method of physical and chemical modeling on the basis of the program Selector complex. The systems were investigated: 1) aluminum oxide - calcium dihydrogen phosphate - water - air; 2) aluminum oxide - ammonium nitrate - water - air; 3) calciumaluminum oxide - potassium chloride - water - air. The following total systems' indexes were counted: isobaric and isothermal capacity of the system, chemical potentials of corresponding independent components, the quantities of components of solution, the amount of allocated gases, pH of the solution, oxidation-reduction capacity of the system. It was revealed that the increase in the content of oxide of aluminum in mixes reduced chemical potential and, therefore, increased the activity of oxygen in all studied systems. The dependence for mix with participation of phosphorus-containing fertilizer, then - potassium-containing fertilizer and, in a little smaller degree, - with participation of nitrogencontaining fertilizer is especially expressed. Thus, clay soils from positions of chemical thermodynamics are favorable concerning the increase in the activity of oxygen when using nitrogen- phospho- rusand potassium-containing fertilizers. In turn, the activity of nitrogen in nitrogen-containing fertilizer (ammonium nitrate) decreases with the increase in the share of a clay-forming mineral. Clay character of soils practically does not influence the activity of phosphorus in phosphorus-containing fertilizer (double superphosphate) and extremely slightly reduces the activity of potassium in potash fertilizer.