基于冠层反射光谱的水稻群体叶片氮素状况监测

 研究了不同氮肥水平下多时相水稻冠层光谱反射特征及其与叶片含氮量等参数的关系。结果表明 ,水稻冠层光谱反射率与叶片氮积累量 (单位土地面积上叶片的氮素总量 )显著相关 ,尤其是近红外与绿光波段的比值(R810 /R560 )与叶片氮积累量 (LNA)呈显著线性关系 ,不受氮肥水平和生育时期的影响 ,回归方程为LNA =0 .85 9R810 /R560 - 1.15 96。利用不同粳稻品种、播期、密度、水分和氮肥处理的数据对方程进行了较充分的检验 ,表明模拟值与实测值之间符合度较高 ,估算精度为 91.2 2 %,估计的RMSE为 1.0 9,平均相对误差为 0 .0 2 6。

Diagnosis of Nitrogen Status in Rice Leaves with the Canopy Spectral Reflectance

The investigation was made on the relationship of seasonal time course canopy spectral reflectance, and ratio index to total leaf nitrogen accumulation(leaf nitrogen content per unit ground area)in rice under different nitrogen treatments. The results showed that a close correlation between the canopy spectral reflectance and total leaf nitrogen accumulation existed. Ratio of near-infrared to green band (R 810/R 560) was linearly related with total leaf nitrogen accumulation, independent of nitrogen levels and development stages. Different datasets were used to test the regression equation, with average estimation accuracy of 91.22%, RMSE of 1.09 and average relative error of 0.026.