Effect of water-fertilizer on maize's water use efficiency and photosynthesis characteristic

Field trials were conducted to study the maize's water use efficiency and synthesis characteristic under different conditions of water and fertilizer.The results showed that under the condition of medium level demand of water(90 m3·hm-2) and fertilizer(N,P,K was 160,60,110 kg·hm-2,respectively),the photosynthetic rate(Pn) and water use efficiency(WUE) were the highest at the blooming stage;in tasseling stage,the stomatal conductance(Gs) and the transpiration rate(E) were the highest.The trends of the photosynthetic rate,transpira-tion rate,water use efficiency and stomatal conductance observed under the different water and fertilizer were indentical respectively in the period of growth.The correlation between transpiration rate and stomatal conductance in medium level demand of water and high level demand of fertility(N,P,K was 240,90,170 kg·hm-2,re-spectively) was significantly higher than in medium level demand of water and low fertility(N,P,K was 80,30,50 kg·hm-2,respectively) and in medium level demand of water and fertilizer significantly;there was a direct correla-tion,linar relationship between the transpiration rate and the stomatal conductance,the stomatal conductance' changes affected the transpiration rate's.