关键词: 玉米, 灌水量, 施氮量, 密度, 干物质积累, 产量

Abstract: In order to definite the response of dry matter accumulation and yield formation of maize to irrigation and nitrogen under different densities，Xundan 509 and Zhengdan 958 were used as materials to study the effects of irrigation amount［reduced irrigation（W1，irrigating 37.5 mm at flare opening and silking stages），full Irrigation（W2，irrigating 75 mm at flare opening and silking stages）］and nitrogen application rate［no nitrogen fertilizer（N0），low nitrogen level（N1，150 kg/ha nitrogen fertilizer），normal nitrogen level（N2，225 kg/hanitrogen fertilizer）］on dry matter accumulation，ear height coefficient，chlorophyll fluorescence parameters（Fv/Fm and Fv/Fo），leaf area index（LAI），yield and its components of maize under different densities［67 500 plants/ha（D1），90 000 plants/ha（D2）］.The results showed that，full irrigation and application of nitrogen both increased dry matter accumulation of population，LAI，Fv/Fm，Fv/Fo，ear height coefficient，yield and its components of two maize cultivars.Simultaneously，the appropriate irrigation amount and nitrogen application rate promoted transfer of dry matter to grain.Increase of density also increased dry matter accumulation of population，LAI and grain yield，while had adverse effects on Fv/Fm and Fv/Fo.Two maize cultivars generally had the highest dry matter accumulation of population，LAI and grain yield under D2W2N2 treatment. Compared with D1W1N0 treatment，the yields of Xundan 509 and Zhengdan 958 increased by 60.76% and 55.38% under D2W2N2 treatment respectively.Overall，D2W2N2 treatment with nitrogen application rate of 225 kg/ha，irrigating amount of 75 mm at the flare opening and tasseling⁃silking stages of maize respectively，and density of 90 000 plants/ha is the optimal measure to obtain high yield under high density.

Key words: Maize, Irrigation amount, Nitrogen application rate, Density, Dry matter accumulation, Yield