Abstract: Potassium fertilizer is one of the important factors which influence the growth and yield of maize. For expounding physiological characteristics and yield traits associated with potassium supplement and optimization of potassium fertilizer suitable amount for high efficient maize production, we monitored the changes of a spring maize‘Zhongdan509’leaves in each growth stage using five levels of potassium sets. The results showed that photosynthetic rate and chlorophyll content showed a unimodal pattern in pace with the increasing use of potassium and reached onto the maximum on the flowering time. Under different potassium treatment, maize photosynthetic rate and chlorophyll content could reach to the maximum at the level of 67.50 kg/hm² accompany with the whole growing period except for maturation. With the increase of the amount of potassium, soluble sugar content of leaves could reach onto maximum at the level of 67.50 kg/hm² throughout the growing period, ultimately, forming a optimal yield of maize. The results showed that potassium supplement possess significant relationship with yield photosynthetic rate, chlorophyll content and soluble sugar content, and suitable potassium supplement would be a best suggestion for enhancing photosynthetic rate and yield.

Key words: maize, potassium fertilizer, photosynthetic rate of leaves, chlorophyll content, yield