Laboratory technical analysis method (electro-ultrafiltration) for the investigation of soil substrates on their available for plants nutrient
, It can all contain all the main nutrients and trace elements nitrogen
(in the form of ammonium and nitrate, as well as organically bound nitrogen). The soil samples are taken before the beginning of the vegetation (February to March) from 0 to 60 centimeters of soil
taken. The subsequent chemical determination of the water-soluble elements and compounds, and their concentration, is carried out with conventional analysis from the extraction solution (atomic spectroscopy or spectrophotometry).
The extraction of nutrients is carried out in a unit specially developed for this process using heating and electricity. In a first step (fraction) the directly available at 30 ° C, 200 volts and 15 milliamps, and in a second step, the potentially available nutrient content (stock) at 80 ° C, 400 volts and 150 milliamps is determined. Depending on the nutrient, the two results are displayed either individually, as a sum or in relation to each other. The analysis serves as a basis for a required fertilization
, See also below Bonitur
and Nmin method