Resumo

SUNER, Liliana G  e  GALANTINI, Juan A. Dinámica de las formas del P en suelos de la región sudoeste Pampeana: Estudio de la incubación con fertilizante fosfatado. Cienc. suelo [online]. 2013, vol.31, n.1, pp.33-44. ISSN 1850-2067.

Different soil P forms exist in a dynamic equilibrium, which depends on the edaphic atmosphere (texture, MO and pH) and on theagronomic management practices (crop rotation and fertilization).The objective of the study was to assess the effect of P application on a soil on the equilibrium of this element. Nine soils were selected and 0, 50 and 100 ìg of P g^-1 were added to these soils. Subsequently, the soil-P mixtures were incubated during 0, 90, 180 and 360 days. The P addition produced an initial decrease of the analyzed P forms. This decrease was more pronounced and persistent in time in the shallow soils. The amount of P-Fe+Al formed during the studied period depended on the soil Fe+Al:Ca relationship, reaching maximum values when the ratio was around 15. In addition, the amount of P-Fe+Al was variable in time and reached maximum values after 180 days of incubation. On the other hand, the formation of P-Ca was much more variable and presented important changes in time. The P balances in shallow soils changed throughout the incubation period; P that was not detected at days 90 and 180 was detected at day 360. These samples were analyzed by electron microscopy and the presence of crystallized substances was observed on days 90 and 180, indicating the formation of P metastable compounds whichcould be one of the transformations that this element suffers in time.

Palavras-chave : Phosphorus fractions; Calcareous soils; P recovery.

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