STUDY OF THE CHEMICAL AND MINERALOGICAL COMPOSITION OF COMPLEX-MIXED FERTILIZERS OBTAINED ON THE BASIS OF VERMICULITE AND SELECTION OF THE OPTIMAL COMPOSITION

Abstrak

The growing demand for multifunctional fertilizers that combine plant nutrition with soil-improving properties has stimulated interest in organomineral compositions based on local raw materials. In the Aral Sea region of Karakalpakstan, large tonnages of phosphogypsum — a by-product of phosphoric-acid production — and deposits of vermiculite, a hydrated Mg–Al–Fe layered silicate, provide a basis for producing complex fertilizer-ameliorants. In such systems biohumus supplies organic matter, ammophos and urea provide phosphorus and nitrogen, phosphogypsum contributes calcium and sulfur, and vermiculite acts as a structure-forming, nutrient-retaining and prolonging matrix. The present work studies the chemical and mineralogical composition of granulated organomineral fertilizers as a function of the phosphogypsum and vermiculite content and selects the optimal composition.