Uso de enmiendas silicatadas en suelos altamente fijadores de fosfatos. II. Efecto de fertilizantes silicofosfatados

Abstract

To study the effects of silicophosphatic fertilizers, two pot experiments were carried out. In the first experiment, increasing doses of five fertilizers (0, 44, 88, 175 and 350 ppm P) were applied to two soils differing in their P fixation capacity. The dry matter production and the P uptake by tomato plants increased proportionally to the P application especially on the high P-fixing soil. Basic slags and Rhenania phosphate yielded higher than fine-grained triple superphosphate. Granulated fertilizers such as Rekaphos and superphosphate showed a better effect due to their slower dissolution. In the second experiment rye grass was used as indicator plant and three successive harvests were made. The fertilizer P effects in this soil with small P-fixing capacity were not too significant and the silicophosphates did not reach the production of superphosphates. The effects of pH, exchangeable Ca and Na showed the composition of silicophosphate and the possibilities of their use as corrective materials.