Organo mineral compound fertilizers are digested with sulfuric acid hydrogen peroxide and nitric acid perchloric acid respectively and then their total potassium content is determined.

The interaction mechanism between humic acid and fertilizer is discussed, the flow sheet, equipment, process parameters of extrusion technology and enterprise standard of product are presented.

By means of consulting a great deal of literature, the authors found that dichromatic oxidation titration method fits for the determination of organic matter in semi-organic fertilizers.