Liquid fertilizers - a solutions that not contain any undissolved substances gaining in popularity over the last few years owing to their ease of use and fast results. Different liquid grades of fertilizer can be produced using a variety of chemicals for grades obtained through the solving process of salts, mineral fertilisers or the special mixing of aqueous solutions [1]. Since they are readily available to the plant, they are immediately absorbed or, if there is an excess, washed away by rain. Since liquid fertilizers do not remain in the soil for long, they will need to be fertilized several times during the growing season. Such intensive and chemical farming is very harmful to the natural ecosystem [2]. This issue raises concerns about soil conservation, soil quality improvement, human health, and environmental protection, driving the search for alternative farming methods. One way to reduce the negative impact on the environment is to use as many biodegradable materials as possible, which not only enrich plants with essential nutrients but also help mitigate various environmental, economic, and social problems [3].
At the beginning of the study, liquid nitrogen-calcium-magnesium fertilisers were developed based on dolomite. The digestion process used 45% nitric acid with a 40% excess of nitric acid, following the stoichiometry of the chemical reaction. The reaction proceeded rapidly, achieving a maximum free decomposition of dolomite (80%) within 50 minutes. The resulting dolomite decomposition solution was then neutralised, and nitrogenous components (urea, ammonium nitrate, potassium nitrate) were added to the composition. These studies on calcium-magnesium-nitrogen fertilisers led to the development liquid fertilisers, whose chemical composition and physicochemical properties were analysed. In response to environmental goals, organic matter extract from biodegradable material, digestate was added to nitrogen-calcium-magnesium fertilizers and physicochemical properties of liquid biofertilizers analysed.