A field trial with flue-cured tobacco conducted on a red paddy soil showed that the dry matter accumulation in the tobacco reached a peak in 50-60 days after transplanting, but was lower within 30 days or over 80 days after transplanting. The dry matter accumulation was increased with increasing K application rate and its supplemental proportion. The K content in the tobacco got its peak in 30-50 days after transplanting, and then went down, with the K content at maturing stage being as half as that in the peak period. The K content of the tobacco in each growth stage was obviously higher with 315 kg x hm(-2) K application than with 225 kg x hm(-2) K application. At maturing stage, the dry matter and K contents in the tobacco decreased with 225 kg x hm(-2) K application, but increased with 315 kg x hm(-2) K application, and the K content was higher with 70% K supplemental proportion than with 50% and 30% K supplemental proportion.