Chemical stability and fertilizer efficiency of bioglass and biochar on rose plantings

Declines in soil quality and low efficiencies of applied fertilizers has limited agricultural productivity worldwide, inducing necessity for sustainable orientated soil amendments. Glass-matrix-based fertilizers are promising "green technologies" thanks to the controlled release of nutrients due to their engineered chemical durability in a wide solubility range. Beside mentioned inorganic soil support, biochar was found to be an effective organic soil amendment that enhances nutrient/water retention as well as microbial activity, making it a promising tool for sustainable agriculture. In this paper, we have tested two possible "green soil amendments": polyphosphate glass (PG) and plum stone biochar (PS) in a 2% citric acid solution, as well as their use as fertilizers on two-year-old rose plantings. The results have shown quick dissolution of PG: nearly 90% for 48 h at 20 °C that steady increase up to 97% at the 480 h; under the same operating parameters, 7.6% of PS was dissolved increasing to 8% at final investigated time. Higher temperatures resulted in higher dissolution rate. The data obtained within the scope of this study indicates that tested fertilizers have a positive effect on rose plant growth, not only promoting bud formation but also extending the flowering period of roses.