Calibration of extractable P (Bray-Kurtz N2 1) for grass-Iegume pastures in soils of Entre Ríos, Argentina

César Quintero G,1, Graclela Boschettl A,1 y René Benavldez Q,1

Pelluderts and Vertic argiudols occupy most of the area in Entre Rios. These soils are characterized by P deficiency and susceptibility to erosion.
The objective of this study was to calibrate the analysis of available phosporus (Bray-Kurtz Nº 1) for pastures in soils Pelludert and Vertic argiudols of Entre Rios, Argentina.
The work was carried out on pastures under rotation grazing in farmers' fields and with different P doses.
The "critical level" was 12 mg kg-1 of extractable-P, below which there is a high probability of response. Classes of fertility were fixed as: very low, low, medium, high, very high; with Iimits of 4.9,10.2,14.9 and 23.1 (mg kg-1), respectively.

Keywords: phosphorus, calibration, soil test, pastures, fertilization, Argentina.
1 Facultad de Ciencias Agropecuarias, Universidad Nacional de Entre Rios, Casilla de Correos 24 (3100), Paraná. Entre Rios, Argentina.