The invention concerns a method for the production of an organic fertilizer of humic-like nature, by oxidising and ammoniating treatment of lignite, characterised by the fact that lignite is suspended in a aqueous ammoniacal medium of pH>9 to 12 and in this context is partially dissolved and is oxidised at a temperature of 20-100° C. at normal pressure; and the organic fertilizer being obtained as a dispersion in aqueous medium, by thickening, or by drying, with a C/N ratio from 9 to 15. An organic fertilizer as well as its use is described. The process enables the production of an organic fertilizer from lignite distinguished by a humus-like structure and slow-releasing fertilization effect, and its use as such or as an addition to yield-increasing and soil-ameliorating substrates.