José F. Araos F.1

The Olsen, Bray Nº 1, Bray Nº2, Truog and North Carolina methods were compared as to their reliability in estimating P avalability on irrigated soils in Ñuble. The simple correlations were calculated between the wheat response to P, in field experiments, and the logarithms of the amounts of P extracted by each method. Eleven experiments were carried out on red soils (alfisols), 11 in trumao soils (andepts) and 11 in miscelaneous soils.

1Ing. Agr. M. S., Centro de Apoyo Suelos, Estación Experimental La Platina, Instituto de Investigaciones Agropecuarias, Casilla 5427, Santiago, Chile.