HOT-WATER PERCOLATION (HWP) - A NEW RAPID SOIL EXTRACTION METHOD

A new, easily applicable soil extraction method has been developed usi ng the coffee percolator principle. The hot water percolation method ( HWP) was examined on 36 soils with different properties. During hot wa ter percolation the available, desorbable, easily soluble elements are extracted by hot water (102-105-degrees-C) at 120-150 kPa pressure. T he average time for one extraction is 2.6 mm. It is possible to carry out kinetic measurements too. Nearly every nutrient is extracted by th is method in measurable quantities, and the macroelements in appreciab le quantities. The variation coefficient (CV%) of the method is in ave rage 11%. The results are in close correlation with those of conventio nal soil testing methods and with the nutrient uptake of the sunflower and ryegrass used as test plants.