拔节抽穗期不同时长干旱胁迫对水稻冠层光谱特征的影响

Spectral Response Characteristics of Rice Canopy Under Drought Stress at Jointing Stage and Heading Stage

基于水稻干旱胁迫试验,采用ASD(Field Spec Pro FR2500)光谱辐射仪测定水稻拔节期和抽穗期不同时间尺度(10d、20d)干旱处理与对照(正常处理)的冠层光谱反射率,对干旱胁迫下水稻冠层光谱变化规律、植被指数、水分指数、导数光谱特征进行分析。结果表明:水稻拔节期和抽穗期干旱胁迫后冠层光谱反射率与对照(CK)相比,可见光、近红外波段反射率均显著减小,短红外波段反射率显著增加,导数光谱红边位置均向短波方向推移,红边面积和红边斜率均显著减少,复合构建的6种植被指数或水分指数呈下降趋势,四波段水分指数(SRND)、归一化差异红外指数(NDVII)下降幅度最大;与CK相比,拔节期干旱胁迫20d和抽穗期10d的水稻冠层对可见光、近红外波段的反射率极显著降低,对短红外波段反射率极显著升高,在此阶段红边特征参数、植被水分指数减少幅度最低。研究结果可为利用高光谱遥感技术快速无损监测水稻干旱灾害提供技术支持。

The canopy spectral reflectance of rice at jointing and heading stage under drought treatment and control （normal processing） was measured by using ASD （Field Spec Pro FR2500） spectral radiometer,the spectral variation of rice canopy,vegetation index,water index,derivative spectral characteristics were analyzed under drought stress.The results showed that the visible and near-infrared reflectance were,under drought stress,significantly decreased than that of CK at jointing and heading stage,and short-infrared reflectance was significantly increased than that of CK,which resulted in all of red edge position of derivative spectra went shortwave direction.Meanwhile,red edge and red edge slope decreased significantly,the composite constructed index of six vegetation index or water index decreased,with the four band moisture index （SRND） and normalized difference infrared index （NDVII） decreased obviously.The visible and near-infrared reflectance rate decreased significantly and short infrared band reflectance rate increased significantly after 20d of jointing and 10d of heading under drought stress.During this period,the red edge characteristic parameters,vegetation moisture index decreased slightly.These results could provide technical for the application of hyper-spectral remote sensing technology to monitor the rice drought rapidly and non-destructive.