Effect of nitrogen and phosphorus on yield and quality of spring maize mulched with plastic film

In this paper, different maize varieties were used to study the effects of nitrogen and phosphorus application on yield and quality indexes of maize with plastic film mulch. The main results were as follows： (1) Nitrogen and variety were the main factors that influenced the yield and seed quality; (2)The protein contents of maize were increased by 0. 63%--0.87% (plastic film mulch) and 0.71%--0.75% (conventional cultivation), and the starch content were decreased by 0.78%-- 1.74% (plastic film mulch) and 0. 54%--1.02% (conventional cultivation) when nitrogen fertilizer was added; (3) Seed bulk density and starch content were increased by 5.8--24.5 g/L and 0.32%--2.69% respectively and proteint content was decreased by 0.29--1.63% by plastic film mulching; (4) Fertilizer application and film mulch had little influence on seed fat and lysine content; (5) Nitrogen or phosphorus fertilizer and plastic film mulch in spring could improve maize yield significantly.