Abstract:Twelve cultivars of Chinese cabbages were hydroponically grown with three different NO3--N/NH4+-N rat ios, i.e., 100:0, 50:50 and 0:100.The result showed that different NO3--N/NH4+-N rat ios had a great effect on the fresh matter weight, chlorophyll content (SPAD readings) and nitrate content of the 12 cultivars of Chinese cabbages.In the same nitrogen source the difference was also significant among the different cultivars.The chlorophyll content of the cabbages increased with the increasing NH4+-N/NO3--N ratio.Except Liangbaiye 1 and Wuyueman both of which had a higher fresh matter weight in a pure nitrate solution than the other solutions with 0:100 or 50:50 NO3--N/NH4+-N ratios, the other 10 cultivars of the cabbages grew best in the solutions with 50:50 NO3--N/NH4+-N.In most of the cabbages the nitrate content decreased significantly with the increasing of NH4+-N/NO3--N ratio.In conclusion, a proper NO3--N/NH4+-N ratio could not only increase the biomass weight and chlorophyll content but decrease the nitrate content of Chinese cabbages as well.