Effect of Coated Urea on Grain Yield and Carbon-nitrogen Metabolism of Summer Maize

The objective of this experiment was to study and evaluate the effects of basal application coated urea and split application(1 :1 and 1 :2 :1) common urea under three application rates(0,90 and 120 kg/ha) on yield and its components,dry matter production and carbon-nitrogen metabolism of summer maize cultivars,Zhengdan958,and to provide some beneficial references for ameliorating the fertilization techniques and increasing crop yield in this area.The main results showed that effect of grain yield,kernel number,dry matter and nitrogen accumulation on sum-mer maize of basal application coated urea and split application(1 :2 :1) common urea treatments were close and they were bigger than other treatments,especially during the late growth stage.The main source of dry grain weight and N accumulation amount of the two advantage treatments were photosynthesis and root absorbed in milk stage,respec-tively.So we could conclude that the capacity of leaves photosynthesis and root absorbed was improved by these two treatments.Meanwhile the results also suggested that total content of soluble sugar and starch in leaf,stem and sheath had reached a suitable and lower value from dough to medium milk stage.