Physiological Response of Potassium Absorption and Utilization of Different Genotypes Rice to Potassium Application Rates

Effects of potassium application rates(0,6,12,18 kg/667 m2 K2O) on plant potassium accumulation,distribution and utilization characteristics of different genotypes rice were studied by using conventional japonica cultivars(Wuyunjing7,Wuxiangjing14) and hybrid japonica cultivars(86you8,Siyou422).The resulted showed as follows.Both rice yield and harvest index were increased with the increment of potassium application,which they obtained the highest at the K2O application rate of 12 kg/667m2.Plant potassium accumulation and absorption percentage from elongation stage to maturing stage were raised,as well as average and maximal rate of potassium speediness accumulation period under potassium application,but starting to terminating date and duration date of potassium speediness accumulation period were opposite.Through potassium fertilizing,plant potassium absorption and the percentage of potassium accumulation from elongating stage to maturing stage were increased.Potassium application promoted potassium distribution amount in leaf,culm and sheath,panicle,and distribution percentage of culm and sheath,whereas reduced distribution percentage of leaf.The variation of potassium distribution amount in culm and sheath were larger than others.With the increment of potassium application rates,rice potassium recovery efficiency,plant potassium productivity and potassium utilization index decreased,potassium agronomy efficiency,physiology efficiency and physiology index increased at first and then decreased.Among these estimation index,the correlation of potassium physiology index and physiology efficiency to yield were higher.Rice yield,potassium absorption percentage from elongation stage to maturing stage,starting to terminating date and duration date of potassium speediness accumulation period,potassium physiology efficiency,potassium physiology index,and plant potassium productivity of conventional japonica cultivars were higher than those of hybrid japonica cultivars,however,potassium accumulation,potassium absorption percentage from transplanting stage to elongation stage,average and maximal rate of potassium speediness accumulation period,potassium distribution amount and percentage in culm and sheath,and potassium recovery efficiency were lower.