不同条件下夏玉米冠层反射光谱响应特性的研究

Canopy spectral reflectance characteristics of summer maize under different conditions

通过对两个年份不同生育阶段的田间夏玉米活体进行冠层反射光谱测定,该文分析了不同空间尺度、种植密度、观测角度、生育阶段、叶面积指数LAI、氮素胁迫、叶片含水量以及与杂草共生等8个条件下的冠层反射光谱响应特性,并探讨其发生机理,研究结果表明,夏玉米在不同条件下的冠层反射光谱响应均呈现出一定的规律性。在近红外波段,其反射率值随氮肥施用量的增加而增大,尤以750～1350nm波段,但在可见光波段,反射率值降低;随着观测探头的逐步升高,反射率值降低;随杂草量的增多,反射率值逐渐增大。这些结果揭示了高光谱遥感田间夏玉米理化信息获取的巨大潜力,同时,为以后遥感反演建模提供了依据。

In the paper, at different growth stages of summer maize, canopy reflectance spectra were measured, and then canopy spectral reflectance characteristics were compared and analyzed synthetically in 2005 and 2006 among different conditions, such as different space scales, different planting densities, different observation angles, different growth stages, different leaf area indexes （LAI）, different nitrogenous （N） levels, different leaf water contents and different weed contents. In the end, the authors probed into the mechanisms of spectral reflectance characteristics above. The results of study indicated that under different conditions, canopy spectral reflectance characteristics of summer maize took on disciplinary change. At NIR （near-infrared bands）, the reflectance gradually increased along with adding nitrogen, especially at 750～1350 nm, but reduced at visible light bands. The reflectance gradually decreased along with escalating the probe, but increased along with developing weed content. The results revealed the tremendous potential of capturing physical and chemical information about summer maize growing in the field using hyper-spectra remote sensing technology, at the same time, provided the basic on constructing retrieved model through remote sensing method in the future.