Polyphosphate glass as fertilizer for plant seedlings

Abstract

Due to the dissolution properties the phosphate glasses can be promising materials for the development of new ecologically safe fertilizers. The complex polyphosphate glass with a molar ratio (M2O + MO)/P2O5 >1 and addition of microelements Zn2+, Mn2+, Fe3+ and Cu2+ were used in substrate for production of flower and vegetables seedlings. Dissolution tests were conducted in deionized water and 2% citric acid. The effects of the reaction time on the normalized glass mass loss (fm) and the normalized concentrations of the ions (fi) at 20, 30, 37 and 50°C were determined. Dissolution rate constants (kw - deionized water, kc -2% citric acid) were also determined (kw-0.0028-0.0094 gm-2, kc-0.029-0.011 gm-2). Values of kc were higher than those of kw, which confirms a significant effect of solvent type and temperature on the dissolution kinetics of glass. The experiments with plants (one vegetable and one flower) showed that the addition of phosphate glass caused an increase in yield and quality of plants. The applied dose of polyphosphate glass of 1gl-1 showed the best effect on the growth of the examined plant seedlings.