Despite their near-equal abundance in Earth's crust, sodium is far more common than potassium in the ocean, both because potassium's larger size makes its salts less soluble, and because potassium is bound by silicates in soil and what potassium leaches is absorbed far more readily by plant life than sodium.
dᵻspˈaɪt ðɛɹ nˌɪɹˈiːkwəl ɐbˈʌndəns ɪn ˈɜːθz kɹˈʌst, sˈoʊdiəm ɪz fˈɑːɹmˌoːɹ kˈɑːmən ðɐn pətˈæsiəm ɪnðɪ ˈoʊʃən, bˈoʊθ bɪkˈʌz pətˈæsiəmz lˈɑːɹdʒɚ sˈaɪz mˌeɪks ɪts sˈɔlts lˈɛs sˈɑːljuːbəl, ænd bɪkˈʌz pətˈæsiəm ɪz bˈaʊnd baɪ sˈɪlᵻkˌeɪts ɪn sˈɔɪl ænd wʌt pətˈæsiəm lˈiːtʃᵻz ɪz ɐbsˈoːɹbd fˈɑːɹmˌoːɹ ɹˈɛdili baɪ plˈænt lˈaɪf ðɐn sˈoʊdiəm.