“叶日积”规律在坡地玉米凹型盖膜种植中的意义新探

New Study on significance of LAI Accumulation over Time in Corn Cultivated with Concave Polythene Mulching on Sloping Land

以往文献计算作物叶日积是将整个生育期分段乘以相应的平均叶面积指数再相加 ,而该文采取对玉米叶面积指数随时间变化的抛物线回归方程求定积分计算叶日积。玉米的最后株高、生育期间的最大叶面积指数和整个生育期的叶日积 ,三者与最终产量均呈显著正相关关系 ,但是叶日积与产量的相关性最高。即在一定栽培密度范围内通过各种途径最大限度地增大叶日积最可能提高玉米最终产量 ,把叶日积看作玉米的一个性状在高产育种中进行收前选择可靠性最高。该研究结果还表明 :凹型盖膜种植并不会改变玉米株高和叶面积指数随时间变化的规律 ,也不会降低玉米最终产量 ,而与传统的凸型盖膜种植相比 ,凹型盖膜种植可减轻坡耕地水土流失。

Different from in previous literature that LAI accumulation over time is calculated by combination of its divided stages,in this paper,it is from definite integration of LAI equation over date Final height,maximum LAI and LAI accumulation over time all were related to corn's yield significantly and positively under a reasonable planting density,but the latter showed best effect Therefore,it will probably enhance corn's yield to make any effort to increase LAI accumulation over time during the growth season,and we can consider it as a trait of corn to select before harvest for high yield breeding Besides,the trial results showed as well that: like traditional convex polythene mulching,concave one also makes a contribution to heat and water conservation in soil,as a consequence of which corn's growth and development is promoted and the yield is increased Compared with traditional convex polythene mulching cultivation,concave one is able to decrease runoff to improve sustainable productivity of crop on sloping field