Three corm conventional multicomponent fertilizers were studied for dissoln. kinetics in distd. water at 25-55 degrees C by conductometry under static and dynamic conditions. For comparison a corm prolongated - release fertilizer was studied by colorimetry and conductometry for 49 days under the same conditions. The full dissoln. of conventional fertilizers was achieved after 10 mm under stirring. The prolongated release fertilizer was dissolved in 11% after 1 day of expt. and in 61% after 28 days. The fastest dissoln. was observed for N compds., and the slowest for K ones.