NOVELTY - Method of producing potassium humate, involves sieving biological ash, removing impurities from the ash to obtain grey powder, filtering furfural residues, grinding the residues to obtain furfural residual powder, mixing the grey powder, furfural powder, alkaline substance and water, stirring and heating the mixture, obtaining precipitate and clear supernatant, adding hydrochloric acid to the supernatant, obtaining precipitate and drying precipitate to obtain potassium humate, stirring and filtering the mixture and subjecting the mixture to granulation process.    USE - The method is useful for producing potassium humate which is used as fertilizer.    ADVANTAGE - The method is cost-effective, simple and reduces environmental pollution as it uses waster materials such as furfural residues and biological ash for producing fertilizer.    DETAILED DESCRIPTION - Method of producing potassium humate, involves collecting biological ash, sieving the biological ash, removing impurities from the biological ash to obtain grey powder, filtering furfural residues, removing impurities from the residues, grinding the residues into powder having particles of 0.1-0.3 mm to obtain furfural residual powder, mixing the grey powder, furfural powder, alkaline substance and water in ratio of 100:150-200:5-10:750-1200, adding the mixture into reaction kettle, stirring the mixture uniformly, heating the mixture at 89-91 degrees C for 2-2.5 hours, terminating heating, placing the mixture in standing position to obtain precipitate and clear supernatant, adding hydrochloric acid to the supernatant, stirring the mixture uniformly until pH of the supernatant reaches 2, placing the mixture in standing position for 8-12 hours, obtaining precipitate and drying precipitate to obtain potassium humate, adding obtained precipitate into sedimentation tank, where the weight ratio of humic acid to the precipitate is 1:0.5-0.8, stirring the mixture uniformly, maintaining the mixture in standing position for 2-3 hours, filtering the mixture and subjecting the mixture to granulation process.