基于高光谱的核桃叶片铁元素含量反演模型研究

【目的】铁元素是评价植物长势的重要指标,监测营养状况是果树栽培管理过程中的主要指标之一。分析核桃叶片Fe素含量与叶片光谱之间的关系,监测核桃活体叶片Fe素含量,为核桃叶片Fe含量快速诊断提供理论依据和技术支撑。【方法】对阿克苏红旗坡地区8个核桃生产园进行随机采样,测定其叶片光谱反射率及Fe素含量,对经过数据变换后的光谱采用逐步线性回归和主成分回归两种方法构建Fe素含量估测模型。用随机分组法选取检验样本并进行精度评价。【结果】经过数据转换的光谱与Fe素含量的相关性明显高于原始光谱,其中以对数二阶光谱725~730 nm、1 140、1 141、1 443、1 444和1 445 nm作为敏感波段构建的主成分回归模型精度最佳,构建模型为y=558.648+113.024 PC₁³-31.514 PC₁²+71.519 PC₁,R²为0.870,RMSE为0.304,RPO为2.39。【结论】光谱技术在开展阿克苏红旗坡地区核桃叶片Fe素含量估算方面具有一定的应用潜力。

Research on the Inversion Model for Predicting Fe Content in Juglans regia L. Leaves Based on Hyperspectral Method

【Objective】 Fe element is an important index to evaluate plant growth, and monitoring nutritional status is one of the main contents in the process of fruit tree cultivation and management. This project aims to realize monitoring of foliar Fe content in Juglans regia L.in vivo by analyzing the relationship between foliar Fe content in Juglans regia L. and foliar spectra in the hope of providing theoretical basis and technical support for rapid diagnosis of Fe content.【Method】Eight Juglans regia L. production garden were selected in Aksu Hongqipo area for random sampling, the spectral reflectance and Fe content of the foliar were measured. The method of stepwise linear regression and principal component regression was used to construct the estimation model of Fe content. Random grouping method was used to select test samples and evaluate the accuracy.【Result】The correlation between the content of Fe in Juglans regia L. foliar and spectra transformed by differential, logarithm and so on was significantly higher than that of the original spectrum. In these data conversions, the highest accuracy of the model was principal component regression model, which was based on the logarithmic second-order spectra of 725-730 nm, 1,140 nm, 1,141 nm, 1,443 nm, 1,444 nm and 1,445 nm. So the optimal model for monitoring foliar Fe element of Juglans regia L. was y=558.648+113.024 PC₁³-31.514 PC₁² +71.519 PC₁, R² was 0.870, RMSE was 0.304, RPO was 2.39.【Conclusion】Spectral technique has a certain application potential in estimating the Fe content of Juglans regia L. in Hongqipo area of Aksu.