Abstract

ZAMUNER, ESTER CRISTINA; LLOVERAS, JAUME  and  ECHEVERRIA, HERNÁN. MÉTODOS AGRONÓMICOS Y AMBIENTALES DE DETERMINACIÓN DE FÓSFORO EN ARCIUDOLES DEL SUDESTE BONAERENSE. Cienc. suelo [online]. 2015, vol.33, n.1. ISSN 1850-2067.

Soil testing is a useful tool for evaluating soil fertility and for making fertilizer recommendations (agronomic tests). Other methods may be used for estimating P that may cause eutrophication of water bodies (environmental tests). Little information is available regarding the relationship between agronomic and environmental soil test methods, for Argiudolls of southeast of Buenos Aires. The objectives of this study were to determine the relationship between agronomic (Bray1, Olsen, Mehlich3) and environmental (CaCl₂) P extraction methods and to determine the risk of contamination with P in potato crops in the southeast of Buenos Aires. The research was conducted in commercial potato fields from 2005 to 2014. Soil samples of unfertilized and fertilized plots with phosphorus (P) were ( 0, 25, 50, 100, 150 and 200 kg P ha^-1). Extractable P by Bray1, Mehlich3, Olsen and 0.01M CaCl₂ methods was determined. Bray1 method extracted the greatest amount of P while Mehlich3 P, Olsen and CaCl₂ removed respectively 10, 25 and 87% less P than Bray1. Linear and significant association was found between agronomic methods (Mehlich3 - Bray1 = 0.80 + 3.45; Olsen - Bray1 + 0.36 = 13.57; Olsen - Mehlich3 + 0.44 = 12.36). Soil P thresholds (39, 34 and 27 mg kg^-1 for Bray1, Mehlich3 and Olsen, respectively) from which P loss from soil to aquatic systems may occur were determined. Bray1 P concentration greater than 39 mg kg^-1 t was associated with risk of P loss in soils cultivated with potatoes, thus warning about the potential environmental impact of P fertilization.

Keywords : Bray.

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