Evaluation of Agriglass as an Environment Friendly Slow Release Fertilizer

Six different agriglass compositions of the (P2O5-SiO2-K2O) system were prepared with the addition of some oxides; Fe2O3, MnO2, ZnO, CuO. Glasses were synthesized by a melting quenching technique at 1150 C-ay. The chemical activity of glass grains of different diameters (0.5 and 1 mm) was estimated by measuring available K2O % by a flame photometer, and P2O5 % by a spectrophotometer, in conditions simulating the plant root zone by shaking in DTPA solution (NH4HCO3-DTPA: ammonium bicarbonate diethylenetriaminepentaacetic acid) for 30 min. The results showed that PS1 glass with main composition (55 P2O5, 5 SiO2, 30 K2O, 5 Fe2O3, 5CuO) wt.%, produced high release nutrient values. The other chemical activity tests were established to evaluate the PS1 glass by shaking in distilled water for 0.5, 1, 2 and 3 hours, and immersion in DTPA solution and 2 wt% citric acid solutions for 1, 2, 3 and 4 months. A greenhouse experiment was performed to evaluate two rates of PS1 agriglass (PS1R1 and PS1R2) compared with the recommended rate of ordinary mineral fertilizers (MF). Although, the effect of MF is higher than both vitreous fertilizer rates in the measurement of 100 grains weight, grains and Stover weight, the application of agriglass with high rate (PS1R2) gave higher results than that of MF in the measurements of ears weight, plant height, and crop weight. It has been found that PS1 glass can be used in practice for maize as an environmentally safe fertilizer.