黑龙江省寒地不同种植密度下高产春玉米冠层结构及光辐射特征

Canopy Structure and Light Radiation of High-yield Spring Maize under Different Planting Densities in Cold Region of Heilongjiang Province

研究不同种植密度下黑龙江省寒地春播郑单958和丰禾1的冠层结构及光辐射特征。结果表明,两个玉米品种在中密度下冠层结构及光分布均较优,产量最高。冠层内光合有效辐射、直射辐射透过系数随密度增加而减小。高密度下叶片分布的极差较大、平均叶倾角最大,其中,吐丝期郑单958叶片分布的极差及平均叶倾角分别达0.35和78.48;丰禾1分别达0.33和61.25。低密度下玉米生育后期叶面积指数最小、叶片分布的极差及光合有效辐射值最大。中密度下郑单958和丰禾1群体平均消光系数最高,吐丝期和灌浆中期分别为0.69～0.74、0.62～0.67;单株叶面积指数吐丝期至成熟期衰退最低,群体内光环境较优,利于玉米叶片的光合生产及最终产量的增加。

The experiment with two cuhivars and three planting densities in the field was conducted to establish quantitative indicators for high yielding cuhivars. The randomized block design was employed with main plot of plant density（low, medium, and high respectively）. The result showed that the high-yielding canopy structure and distribu- tion of light radiation internal canopy structure were obtained under medium densities of the two cuhivars. Photosyn- thetically active radiation（PAR）, transmission coefficient for radiation penetration decreased with the increase of plant density in canopy. The range distribution of leaves were greater, mean foliage inclination angle（MFIA） were highest under high densities, such as Zhengdan958 were 0.35 and 78.48, and Fenghel were 0.33 and 61.25 in silking stage. The later growth stages leaf area index（LAI） was smallest, range distribution of leaves and photosynthetically active ra- diation（PAR） were the highest under low densities Results confirmed that proper planting density can establish high-yielding canopy structure and improve population light environment and yield in maize.As for Zhengdan958 and Fenghel, population average extinction coefficient was highest, reaching 0.69-0.74 in silking Stage and 0.62-0.67 in mid-filling stage under medium density. From silking stage to maturity, the leaf area index（LAI） of zhengdan958 and Fengheldeclined to the lowest under medium density, reaching 17% and 27% respectively, which giving a good foun- dation for the photosynthesis production and yield increasing.