宁夏引黄灌区玉米高产挖潜群体特征分析

Analysis of Maize Potential Yield and Population Characteristics In Ningxia Irrigation Area

为了探明宁夏玉米高产群体特征以及限制高产的因子。以‘郑单958’和‘先玉335’为供试品种,在密度为121215株/hm^2和110205株/hm^2下对产量及产量构成、关键生育时期的群体光合性能、干物质动态变化等特征进行研究。结果表明:群体叶面积指数(LAI)随生育进程呈单峰曲线变化,吐丝前后达到最大值;光合有效辐射量沿冠层垂直向下呈大幅下降,以120~180 cm处(棒三叶位置)透光率的变化最为明显;整个生育期群体干物质积累动态呈S形曲线,成熟期干物质积累最大;2种不同高产挖潜模式均可获得高产;但‘先玉335’挖潜模式群体结构更为理想,后期氮肥供应不足是产量限制因子。因此认为,‘先玉335’在原密度下,后期通过增施N肥,来增加千粒重和穗粒数,是宁夏进一步提高玉米产量的重要途径。

To ascertain the population characteristics of high-yield maize in Ningxia and the factors that limithigh yield,‘Zhengdan 985’and‘Xianyu 335’were chosen as the experimental cultivars with the plantingdensities of 121215/hm^2 and 110205/hm^2. Yield and yield components, the group photosyntheticcharacteristics at key growing stages and the dynamic change of dry matter were studied. The results showedthat： leaf area index（LAI） showed unimodal curve change and reached the highest value around silking stage.The photosynthetic effective radiation showed a sharp decreasing trend with the canopy downward and thechange of light transmittance was the most obvious at the position of 120-180 cm. The dynamic change of drymatter accumulation showed an‘S’shaped curve in the whole growth period and it reached the highest at thematurity stage. High yield could be obtained by following the two different modes of yield potential digging.‘Xianyu 335’was more ideal for achieving high yield but the lack of nitrogen supply at the late growing stagewas the limiting factor for high yield achievement. Therefore, in the original density of‘Xianyu 335’,increasing N fertilizer application at the late growing stage to increase 1000-kernal weight and grain numberper ear was an important way of further increasing maize yield in Ningxia.