The aim of the study was the preparation and characterization of organo‐mineral fertilizers supporting sustainable development of agriculture. Materials were obtained by the drum granulation in laboratory conditions and by the pan granulation on a semi‐industrial plant. On a laboratory scale, three fertilizer formulas NPK 5‐10‐20, NPK 4‐18‐23, and NPK 3‐10‐12 and 60 fertilizer formulations modified with three different organic materials (lignite, peat, and compost), with five levels of their content (5%, 10%, 15%, 20%, and 30%) were prepared. The effect of granulation on a semi‐industrial scale was two fertilizer formulas: NPK 5‐10‐20 and NPK 4‐18‐23, with three levels of lignite content (10%, 20%, and 30%). In the obtained materials, the granulometric composition, static and dynamic strength as well as the content of macro and micronutrients were analysed. The properties of the produced fertilizing materials were also verified in microbiological experiments. Based on the experiments carried out, it was found that the only formula that met the legal and quality requirements would be the NPK 4‐18‐23 formula with ≈20% lignite content. It was found that the organic materials used are not a source of microorganisms in the prepared fertilizers, and these fertilizers would meet the requirements of the regulations.
Wróblewska et al. (Thu,) studied this question.