ABSTRACT
Fertility changes detected in Chilean soil profiles. IV. With the Iixiviation of five potassium sulphate doses in a Pemehue soil of Vilcun

Gotardo Schenkel S.1, Pedro Bahere V.2 y Mauricio Gajardo M.3
 

The lateral and vertical movement of K is studied, when K2SO4 (analytical reagent) is added to the suríace of a soil (Trumao Pemehue) of the Cautín Province. Five doses (0, 16, 48, 160 and 480 kg) of K2O/hectare were added, through a percolator inserted, under pressure, in a field previously occupied with a pasture never fertilized with K. The pattern of the exchangeable K distribution curve, in the soil profile free from vegetation, is modified by the doses added and by factors pertaining to the soil. For the fertilized soil, the distribution follows a model that distinguishesthree zones: a. one, of largest enrichment (0-30 cm), very dependent Qn the amount given by the fertilization; b. a second, of intermediate enrichment (30-110 cm), modified only tilI 70cm, for the lower amounts of K supplied; and c. a third zone (110-200 cm), practically unaffected, except slightly with the two heavier doses of K2O. The highest exchangeable K concentration is detected for alI treatments at the same depth (15 cm), being the distance from the surface independent of the K dose. However, the amount of exchangeable K present at 15 cm, as well as in the 0-30 cm depth, depends on the fertilization. The same Pemehue soil, never fertilized with K, exhibits a remarkable uniformity, for the exchangeable and the accumulated K fractions, under seven successive extractions, from the top down to 200 cm depth. The comparison of both fractions indicates the existance of a strong K reserve in the whole prof ile. Results obtained suggests that only very low K losses by lixiviation do exist, in this deep Pemehue soil without vegetation.

Keywords:
1 Facultad de Ciencias Agropecuarias y Forestales, Universidad de Concepción, Casille 537, Chillán, Chile.
2 Estación Experimental La Platina (INIA), Casilla 439, Correo 3, Santiago. Chile.
3 Estación Experimental Carillanca (INIA), Casilla 58-D, Temuco, Chile.