INFLUENCE OF SOLID LIQUID STATES RATIOS ON THE COMPOSITION AND PROPERTIES OF HUMATE-CONTAINING ORGANO-MINERAL FERTILIZERS

Abstract

Introduction. Human economic activity leads to removal of nutrients from the soil along with the crop. Nutrients losses also occur because of natural processes (erosion, leaching, etc.). It is necessary to replenish the missing nutrients with the use of humate-containing organomineral fertilizers to preserve soil fertility and increase productivity. The purpose of this work is to study the processes of iron (III) phosphates interaction with potassium humate and to obtain humate-containing organomineral fertilizers. Methodology. Chemical analysis, infrared spectroscopy, X-ray phase analysis methods have been used. Results and discussion. The processes of obtaining humate-containing organomineral fertilizers by the interaction in the systems “iron dihydrogen phosphate - potassium humate”, “iron hydrogen phosphate - potassium humate” and “iron orthophosphate - potassium humate” have been studied. It has been determined that an increase in the S:L ratio from 1:3 to 1:6 leads to an increase in the content of the digestible forms of Р₂О₅ up to 44.70%, nitrogen up to 1.85% and the output of humic substances up to 79.23%. An analysis of the IRS data indicates the multicomponentness and complexity of the composition of humate-containing organomineral fertilizers samples. Conclusion. It has been shown that the absorption bands of humic compounds of various functional groups and various substitutions phosphates are superimposed, while the shape of the absorption bands distorted, and their maxima have shifted to the high- or low-frequency area. It has been found that, regardless the phosphate ionnature, an increase in the ratio of S:L leads to a decrease in the absolute content of total, water-soluble and assimilable forms of P₂O₅. Concurrently, the phosphate part almost completely converted into the assimilated form. It has been defined that adding of the potassium humate, makes all phosphorus, which is in the indigestible form in the iron phosphates, almost completely pass into a mobile and assimilable form. It has been revealed that the addition of potassium humate into the systems with iron phosphates of various degrees of substitution makes it possible to neutralize the residual acidity of the pulp, and the neutralization process proceeds without P₂O₅ retrogradation. The resulting products have good physical, mechanical and fertilizer properties.