## 3 Results and Discussion  
### Description of the Fertilizer's Functionality  
Calcinated bones mainly consisted of phosphorus, calcium and magnesium compounds [17]. The forms in which these elements are found are mainly insoluble, which limits their absorption by plants. One way to increase the mobility of these ingredients is to convert them into soluble forms. This can be achieved using strong mineral acid solutions. The presence of calcium compounds in the raw material eliminates the possibility of using the popular sulfuric acid, due to the formation of gypsum. Nitric acid as a strong acid can be used to solubilize thermally processed waste components. However, its use is problematic due to the possibility of NOx emission [19]. This problem was solved by using appropriate nitric acid solutions [20]. In this way, 95% of the components of thermally processed bone waste were recovered. A fraction rich in phosphorus, nitrogen, calcium, and magnesium compounds was obtained. Boric acid and the addition of glycine were used in the granulation process, which allowed the attainment of granules with appropriate mechanical properties. The addition of these two components not only enabled the granulation process, but also enriched the fertilizer with plant nutrients supplied by foliar fertilization. The developed fertilizer mainly contained: 48.8 g kg\({}^{-1}\) P, 12.5 g kg\({}^{-1}\) N, 80.3 g kg\({}^{-1}\) Ca, 4.4 g kg\({}^{-1}\) Mg, and 70 g kg\({}^{-1}\) B [17; 20]. It should be noted that the composition of the foliar fertilizer obtained is unique because it allows the coexistence of calcium and phosphorus compounds remaining in a soluble form, which are thus available to plants in one fertilizing product.  
Micogranules for initial fertilizing were mainly produced from thermally processed bone waste (79%), lake chalk (19%), and whey protein isolate (2%). The mineral composition of soil fertilizer was: 136.81 g kg\({}^{-1}\) P, 3.93 g kg\({}^{-1}\) Na, 29.96 g kg\({}^{-1}\) K, 13.20 g kg\({}^{-1}\) Mg, 347.81 g kg\({}^{-1}\) Ca, 3.2 N g kg\({}^{-1}\), 1 mg kg\({}^{-1}\) Fe, 6.5 mg kg\({}^{-1}\) Mn, 0.8 mg kg\({}^{-1}\) Zn, and 3.2 mg kg\({}^{-1}\) Cu (Patent 2019). It has been shown that the components of micro-granules, especially calcinated bones, despite their low solubility, show a strongly alkaline character. Alkaline compounds break down organic matter rich in nitrogen compounds, including protein that is part of the fertilizer, and one of the products of this decomposition is nitrogen in the form of ammonium [21]. This decomposition is controlled and spread over time. As shown [21], the maximum concentration of ammonium nitrogen occurs after 5 days from the application of fertilizer to the soil, with appropriate humidity conditions. If the soil moisture level allows maize seeds to germinate, the process of protein degradation and the release of ammonium nitrogen also begins. These decomposition products are available in a relatively high concentration in the immediate vicinity of the growing root system of plants, which correlates with the nutritional requirements of plants in the early stages of their development. Only the right P:N ratio ensures proper plant growth and development. The rate of phosphorus absorption depends on the form of nitrogen. Ammonium nitrogen acidifies the soil solution, which usually increases the phosphorus concentration and the rate of absorption of this element by plants. In turn, the nitrate form of nitrogen causes alkalization of the soil solution, which reduces phosphorus absorption [7]. Other mineral components are available to plants at a later stage after the fertilizer is being broken down by the soil microbiome [22; 23].  
It should be noted that micro-granules with a moisture level below 5% are stable, which allows them to be transported and stored without loss of product quality.