消光系数估算方法对玉米冠层光能利用模拟的影响.

A field experiment for the AD268 with large leaf and dwarf structure and the XY335 with small leaf and high structure at three planting densities of low (3 plants·m-2), medium (6 plants·m-2) and high (9 plants·m-2) was conducted. This study integrated the vertical distribution of canopy photosynthetically active radiation (PAR), a 3D canopy model, and a canopy photosynthesis model to analyze responses of the extinction coefficients estimated by the logarithmic approach (klog) and the regression approach (knls) to cultivar and density and their differences, and to evaluate the effects on simulating canopy light utilization. The results showed that there was a difference between klog and knls, and this difference was more obvious for AD268 and aggravated with increasing density. The fitness based on knls for canopy light distribution (R2=0.86) was better than klog (R2=0.77). The daily CO2 assimilation, above-ground dry matter accumulation and radiation use efficiency of AD268 simulated by klog and knls did not differ significantly at low densities, but the difference became larger with increasing density. The critical densities at which the difference become larger were 0.7-2.5plants·m-2. [ABSTRACT FROM AUTHOR]