A procedure is described for bringing into solution the total content of copper, iron, aluminon, manganese and phosphorus, followed by the colorimetric determination of those ele ments. The procedure consists of heating 250 or 500 miligrams of the prepared soil samples with 1.5 to 3.0 ml of perchloric acid and 5.0 to 8.0 ml of hydrofluoric acid. Copper was determined by the diethyldithiocarhamat method; iron, by the 1,10-phenanthrolim method; aluminum,by the aluminon; manganese, by the permanganate; and phosphorus by the molybdenum blue mehtod, using ascorbic acid as reductor.