毛竹林叶片磷和钾含量的不同尺度光谱响应研究

Spectral Response of Phosphorus and Potassium Content in Phyllostachys pubescens Leaves at Different Scales

研究不同尺度光谱对毛竹林叶片磷和钾含量的响应机制,对实时掌握毛竹林生长状况和营养水平有理论意义和实践指导价值。以毛竹林叶片与冠层2个尺度的原始光谱为数据源,通过一阶微分光谱等光谱变换,采用回归统计分析构建不同尺度磷素和钾素含量与敏感波段的光谱估算模型,并对其稳定性和预测性进行精度评价。结果表明:叶片光谱分析中以磷含量一阶微分光谱为变量的线性回归方程模型拟合精度高达74.90%,且在建立专一性较高的磷素含量估算模型上更有优势;冠层光谱分析中以钾含量一阶微分光谱为变量的线性方程模型拟合精度高达78.71%,且在建立专一性较高的钾素含量估算模型上更有优势;同时,一阶微分光谱可降低空间异质性以提高光谱估算模型反演精度。

The responses of different scales of spectrum to phosphorus and potassium contents in leaves of Phyllostachys pubescens were studied, aiming to provide references for grasping Phyllostachys pubescens growth and nutrient level. Taking the original spectrum of leaf and canopy of Phyllostachys pubescens as the data source, through the conversion of the first derivative spectra, the spectral estimation models of phosphorus andpotassium contents and sensitive bands at different scales were constructed by regression analysis, the stabilityand predictability were evaluated. The results showed that the fitting precision of linear regression equationmodel with the first order differential spectrum of phosphorus content in the spectral analysis was 74.90%, andit had an advantage in establishing a model with higher specific phosphorus content. In the canopy spectrumanalysis, the fitting precision of linear equation model with the first order differential spectrum of potassiumcontent was 78.71%, and it was more advantageous in establishing the model with high specificity ofpotassium. At the same time, the first order differential spectrum could reduce the spatial heterogeneity to improve inversion accuracy of the spectral estimation model.