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通过不同夏玉米品种生育期内冠层叶片含水率与不同波段组成的比值指数(RVI)和归一化植被指数(NDVI)进行线性、指数、对数、幂函数以及多项式回归分析,研究不同品种夏玉米的冠层叶片和植株水分状况与反射光谱之间的相关关系。结果表明,冠层叶片和植株含水率与460～670nm范围内波段反射率均成负相关,与730～1260nm范围内波段反射率均成正相关。其中冠层叶片含水率与460、500、600、650、670nm范围内波段反射率均呈显著相关,而植株含水率与460、500、600、650、670、780、800、850、900、950、1050nm范围内波段反射率相关性也较高。冠层叶片含水率与归一化植被指数(NDVI)相关性均达到极显著水平,与比值指数(RVI)相关性中只有RVI(950,550)、RVI(850,730)、RVI(800,730)和RVI(780,730)4个波段呈极显著正相关。RVI与叶片含水率相关性以RVI(850,730)最优,NDVI与叶片含水率相关性以NDVI(1050,550)最优。植株含水率也与RVI和NDVI呈正相关,相关性均较好,但NDVI优于RVI。RVI与植株含水率相关性以RVI(800,500)最优,决定系数为0.8490;NDVI与植株含水率相关性以NDVI(780,650)最优,决定系数为0.8645。
Through the linear, exponential, logarithmic, power function and polynomial regression analysis of the RVI and NDVI of the canopy leaf water content in different summer maize varieties during different growth stages, Correlation between Canopy Leaf and Plant Water Status and Reflectance Spectrum of Summer Maize. The results showed that the water content of canopy leaves and plants was negatively correlated with the band reflectivity in the range of 460-670 nm, and positively correlated with the band reflectivity in the range of 730-1260 nm. The water content of canopy leaves was significantly correlated with the band reflectivity in the range of 460, 500, 600, 650 and 670 nm, while the water cut of the plants was related to 460,500, 600,650, 670,780,800, 850,900,950 , 1050nm band reflectance correlation is also higher. The correlation between the water cut of canopy leaf and normalized vegetation index (NDVI) reached extremely significant level, and only RVI (950,550), RVI (850,730), RVI (800,730) and RVI (780,730) ) 4 bands showed a significant significant positive correlation. The correlation between RVI and leaf water content is optimal for RVI (850,730), and the correlation between NDVI and leaf water content is best for NDVI (1050,550). The water cut of plants was also positively correlated with RVI and NDVI, but the correlation was better, but NDVI was better than RVI. The correlation coefficient between RVI and plant water content is the best with RVI (800, 500), and the coefficient of determination is 0.8490. The correlation between NDVI and plant water content is best with NDVI (780, 650) and the coefficient of determination is 0.8645.