Abstract: Relevance of use of complex fertilizers, in particular the application of ammonium sulfate, humates and saponite. Selected physical and mathematical model of heating of the composite granules of ammonium sulfate in the presence of saponite and humates. Solved mathematical model and tested its adequacy.

Key words: Ammonium sulfate, humates, complex fertilizers, saponite, mathematical model.

Abstract: Proposed and validated a mathematical model of drying process of complex fertilizers. The obtained dependence of the temperature of the drying granules of the radius and time.

Key words: nitrate, sulphate, potassium, humates, mineral and organic fertilizer, granulation.