琯溪蜜柚叶片氮素含量多种高光谱估算模型对比研究  

Comparative study on several hyperspectral estimation models of nitrogen contents in Guanxi honey pomelo leaves

作　　者：栗方亮[1] 孔庆波[1] 张青[1] 庄木来 LI Fangliang;KONG Qingbo;ZHANG Qing;ZHUANG Mulai(Institute of Soil and Fertilizer,Fujian Academy of Agricultural Sciences,Fuzhou 350013,Fujian,China;Agricultural and Rural Affairs Bureau of Pinghe County,Pinghe 363700,Fujian,China;Pinghe Guanxi Honey Pomelo Comprehensive Test Station,Pinghe 363700,Fujian,China)

机构地区：[1]福建省农业科学院土壤肥料研究所,福州350013 [2]福建省平和县农业农村局,福建平和363700 [3]平和琯溪蜜柚综合试验站,福建平和363700

出　　处：《果树学报》2022年第5期882-891,共10页Journal of Fruit Science

基　　金：福建省属公益类科研院所基本科研专项(2021R1025008);福建省自然科学基金(2019J01106);“十三五”国家重点研发计划(2017YFD0202000)。

摘　　要：【目的】蜜柚叶片氮素(nitrogen,N)含量是准确诊断和定量评价生长状况的重要指标,建立合适的蜜柚叶片氮素含量高光谱估算模型,为实现快速、无损、精确的氮素含量估测提供依据。【方法】基于蜜柚叶片高光谱数据和氮素含量实测数据,建立了蜜柚叶片偏最小二乘回归模型(PLS)、BP神经网络回归模型(BPNN)、随机森林回归模型(RF)和支持向量机回归模型(SVM),并确定了蜜柚叶片氮素含量最佳估算模型。【结果】原始光谱和一阶微分光谱与蜜柚叶片氮素含量在可见光范围内有多波段相关性显著,并出现多个极值。原始光谱曲线敏感波长为569 nm和704 nm,一阶微分曲线的敏感波长为541、617、695、753 nm。与蜜柚叶片氮素含量相关性较显著的光谱参量是NDVI′_(695,753)、RVI′_(695,753)、DVI′_(617,695)、R′_(617)、DVI′_(541,617)。建立的PLS、BPNN、RF和SVM 4种蜜柚叶片氮素含量估算模型的决定系数R^(2)分别为0.75、0.80、0.83和0.81,均方根误差RMSE分别为1.16、1.08、0.97和1.02。验证模型的决定系数R^(2)分别为0.79、0.84、0.85和0.82,均方根误差RMSE分别为1.11、0.94、0.87和0.99,其估算模型的精确程度为RF>SVM>BPNN>PLS。【结论】通过对琯溪蜜柚叶片氮素含量进行4种高光谱估算模型对比,随机森林估算模型精度稍高于PLS、BPNN和SVM估算模型。研究结果为光谱监测蜜柚叶片氮素含量提供了技术依据。【Objective】Nitrogen(N)content in pomelo leaves is an important index for accurate diagnosis and quantitative evaluation of growth status.Timely and accurate nitrogen diagnosis is an important and key work in precise agriculture.Hyperspectral technology can directly and quantitatively analyze weak spectral differences,which provides a good method for quantitatively analyzing the correlation between plant N contents and spectral parameters.Therefore,the hyperspectral estimation models of N contents in the pomelo leaves were established to provide a basis for rapid,nondestructive and accurate estimation of N content.【Methods】Based on the hyperspectral data of the pomelo leaves and the measured data of N contents,the study firstly analyzed the correlation between the N contents of the pomelo leaves and their original and first-order differential spectra,then analyzed the correlation between spectral characteristic parameters,sensitive band vegetation indices and the nitrogen contents of the pomelo leaves,and found out the spectral parameters with good correlation,finally the partial least squares regression model(PLS),BP neural network regression model(BPNN),random forest regression model(RF)and support vector machine regression model(SVM)of the pomelo leaves were established,and the best estimation model of N contents in pomelo leaves was determined.【Results】There were negative correlation between the original spectral reflectance of the pomelo leaves and the leaf nitrogen contents.The maximum negative correlation coefficients were(-0.683,569 nm)and(-0.688,704 nm),respectively;there were extremely significant negative correlations between nitrogen and firstorder spectral reflectance in the bands of 440-455 nm,490-553 nm and 681-705 nm(p<0.01),among them the maximum negative correlation coefficient was(-0.72,695 nm),followed by(-0.70,541 nm);in the bands of 586-627 nm,633-671 nm and 731-758 nm,it reached extremely significant positive correlation level(p<0.01),among them the maximum positive correlation c

关 键 词：蜜柚 高光谱 氮素 光谱指数 

分 类 号：S666.3[农业科学—果树学]