Identification of primary substrates in organo-mineral fertilizers by means of isoelectric focusing

Organo-mineral fertilizers (OMF) are used to improve the efficiency with which plants absorb the nutrients contained in mineral fertilizers, thanks to the properties of the fertilizer's organic component. The quality of the organic component, and hence its origin, is of primary importance for its efficient use in agriculture as a fertilizer. It is thus necessary to identify analytical techniques which are able to distinguish the primary substrates in a mixture, as well as their humification levels. In this study, isoelectric focusing was used to recognize the four primary substrates fi om different organo-mineral fertilizers containing peat, leather meal, poultry manure, or dried pig slurry. The experiments gave positive results. Peat could be distinguished from leather meal, although poultry manure was not distinguishable from dried pig slurry.