ChileanJAR

The effects of temperature, type of shaker, centrifugation, shaker's velocity and type of receptade upon P-Olsen determinations were studied, in 43 volcanic ash soils of the Araucanía Region of Chile. Two types of shakers (reciprocal and rotatory), three velocities (160-180-200 oscillations/min), two types of receptades (plastic, square base, and glass, round base) and two extraction temperatures (15 and 25ºC) were considered. Besides, ryegrass H-l dry matter yields were determined, in pots in the greenhouse, and were correlated with P-Olsen analytic values. A largest amount of P was extracted at 25ºC, with centrifugation and reciprocal shaker, as compared with 15ºC, no centrifugation and rotatory shaker. Moreover, by using plastic square base receptacles and shaking speeds of 160 and 180 osc/min, greater amounts of Pare extracted, as compared with glass round base receptades.