Effects of Potassium Levels on Yield and Potassium Utilization of Chinese Cabbage under Open Vegetable Field

This study was conducted to determine the effects of potassium levels on yield,nitrate and nitrogen utilization of Chinese cabbage under open vegetable field with relatively low soil potassium fertility level by the field experiment in He village,Zhonghan town,Gaoyi county in Hebei province.The results showed that significant increases in yield of Chinese cabbage at K2O rates below 450 kg/ha were found,and potassium application averagely increased yield of Chinese cabbage by 8.7%,with the highest yield at K2O rates of about 225 kg/ha applied.Potassium application averagely decreased contents of nitrate in Chinese cabbage edible parts by 12.9%.Distinct increases in biomass accumulation of rosette leaves,heading leaves and total plants(rosette leaves+heading leaves)by potassium application were observed,with respective average increases being 40.9%,21.2% and 28.9%,and the highest or relatively high biomass accumulation at K2O rates ranging from 150 to 300 kg/ha applied.Obvious increases in potassium uptake of rosette leaves,heading leaves and total plants by potassium application were found,with respective average increases being 49.7%,18.2 and 30.8%,and the highest or relatively high potassium uptake at K2O rates of about 300 kg/ha applied.Relatively high recovery rate(31.5%-61.2%)of applied K2O below 300 kg/ha and agronomic efficiency(42.8-105.5 kg/kg)of applied K2O below 225 kg/ha was observed.The proper rate of K2O of Chinese cabbage based on yield,biomass accumulation and distribution,potassium uptake and distribution,and potassium use efficiency ranged from 225 to 300 kg/ha under this experimental condition.