A field experiment was  carried  out  at the Experimental Farm of El-Gemmeiza, Agric. Res. Station, El-Gharbeya Governorate, Egypt , during 2019 and 2020 summer seasons,to study the effects of different rates  of potassium treatments  at 48, 72 and 96 kg/fad. K₂O as soil application and  K₂O concentration treatments  at 0,0.5 and 1.0%  as  foliar  application and their interactions  on growth, yield  and tuber quality of Jerusalem artichoke Fuseau  cultivarunder clay soil.The interaction treatments  of  fertilizing Jerusalem artichoke with   K₂O at 72 kg /fad. as soil application (SA)  and spraying plants  with K₂O at 1 %  four   times  at 75, 90,105 and 120 days after  planting  had significantly increased  on plant height , number of branches /plant,both fresh and dry weight of shoots/plant, N,P and K  contents  in shoots and its uptake,  average tuber weight , yield / plant  and total yield/faddan .While,the  interaction treatment   between  K₂O  at 96 kg /fad. as  soil application  and  spraying plants with K₂O at 1%  reflected a significant effect and increased total carbohydrates , inulin,K and dry matter percentages  in tuber at harvest time  compared with  plants received  K₂O at 48 kg /fad. as SA only  in both seasons. Finally, under the same conditions, fertilizing Jerusalem artichoke with K₂O at72 kg/fad. as  soil application  and spraying plants  with  K₂O  at 1% reduced  the  using  of potassium fertilizer  by 25% and increases in total yield about 9.89 and 6.91 % over fertilizing with 96 kg /fad. K₂O only in the 1^st and 2^nd seasons, respectively.