棉花冠层不同尺度光能空间分布特征研究

摘要

[目的]棉花冠层光能空间分布是光能利用率高低的直接影响因素之一.为科学量化光能在棉花冠层的空间分布,本研究旨在分析冠层内光合有效辐射(Photosynthetically active radiation,PAR)各分量的空间变化特征.[方法]用空间统计学方法分析了冠层不同空间点、线、面位置PAR的分布特征.[结果]盛花期棉花行间冠层PAR截获率整体变化呈“V”形,即棉行间PAR截获率低于棉行附近位置;高密度的群体冠层中下部PAR截获率纵向变化速率较缓,同时在距地面60 cm处PAR截获率横向变化幅度也较小;不同冠层区域的PAR截获率与密度呈正相关关系,且随播种后时间均呈现先增后减的变化趋势.[结论]适当增大种植密度可以提高群体PAR截获率.运用空间统计学原理精确定位定量分析冠层内PAR的分布,对合理配置棉花种植模式、研究群体株型结构、培育高光效品种具有指导意义.%[Objective] Cotton canopy photosynthetically active radiation (PAR) spatial distribution is a significant factor in the light energy coefficient of utilization.The aim of this study is to analyze spatial distribution characteristics of each component of PAR.[Method] PAR spatial distribution in the cotton canopy was presented intuitively using a geo-statistical method.[Result] (1) At different points,PAR spatial distribution was a "V" shape at the flowering stage.However,a short and shallow "V" shape was observed with high plant population density (PPD).(2) At different profiles,the PAR interceptions changed slightly in the vertical direction of the middle-lower canopy;and the extent of variation was small in the horizontal direction,60 cm from the ground.(3) At different layers,PAR interceptions increased with PPD.In the horizontal direction,PAR interceptions between two adjacent cotton rows were lower than that between nearby cotton rows;in the vertical direction,PAR interceptions in the lower layers were above 0.83,and 0.27 less than in the upper layers.[Conclusion] PAR interception can be increased by increasing PPD suitably.Using geo-statistives to quantify PAR spatial distribution within the cotton canopy precisely and accurately is of great significance for reasonable plant density arrangement,plant architecture molding,and yield improvement variety selection.