Abstract:Chlorophyll is an important biochemical parameter involved in crop growth. Accurate detection of chlorophyll in real-time has great significance for the precision management of farmland. The PROSPECT model can simulate the reflectivity and transmissibility of leaf at 400~2 500 nm based on leaf’s input structural and biochemical parameters. This study used the PROSPECT model to generate 10 650 reflectivity curves of maize leaf under different input parameters. The sensitivity of the spectral reflectance curve to the chlorophyll content parameter was analyzed when other parameters remained unchanged. The result shows that the chlorophyll content only affects the spectral reflectance curve in the range of 400~780 nm. According to the sensitivity analysis result, 76 wavelengths in 548~610 and 694~706 nm were selected as the characteristic wavelengths of chlorophyll content, which were recorded as SEN-BAND. Based on Backward Interval PLS (Bi-PLS), 5 intervals of 91 characteristic wavelengths were selected, recorded as BP-BAND. Based on the Successive Projections Algorithm (SPA), 10 characteristic wavelengths were selected in chlorophyll-influenced area in 400~780 nm, recorded as SPA-BAND. The PLS detection model of chlorophyll content based on the three characteristic wavelengths was constructed with measured field data in 2019 and 2020. The results show that the -SPA-BAND model has the best results in both 2019 and 2020 datasets. In the 2019 dataset, the coefficient of determination (R2c) of the modeling set is 0.815 6, the root mean square error (RMSEC) of the modeling set is 2.908 6, the coefficient of determination (R2v) of the validation set is 0.799 5, and the root means square error (RMSEV) of the validation set is 2.997 7. In the 2020 database, the coefficient of determination (R2c) of the modeling set is 0.949 2, the root mean square error (RMSEC) of the modeling set is 0.976 8, the coefficient of determination (R2v) of the validation set was 0.910 2, and the root means square error (RMSEV) of the validation set was 1.562 9. Therefore, the characteristic wavelength of chlorophyll content can be selected under the influence of multiple factors by constructing spectral reflectance curves with multi-parameter input based on the PROSPECT model and the characteristic wavelengths of chlorophyll content can be verified in multi-year data.
[1] HE Yong,PENG Ji-yu,LIU Fei,et al(何 勇,彭继宇, 刘 飞, 等). Transactions of the Chinese Society for Agricultural Engineering(农业工程学报),2015,31(3): 174.
[2] WANG Hao-yun,CAO Xue-lian,SUN Yun-xiao,et al(王浩云,曹雪莲,孙云晓,等). Transactions of the Chinese Society for Agricultural Machinery(农业机械学报),2021,52(3): 202.
[3] WANG Qi,SONG Xiao-yu,YANG Gui-jun,et al(王 琦, 宋晓宇, 杨贵军, 等). China Agriculture Information(中国农业信息),2018,30(6): 35.
[4] SUN Hong,CHEN Xiang,SUN Zi-chun,et al(孙 红,陈 香,孙梓淳,等). Transactions of the Chinese Society of Agricultural Machinery(农业机械学报),2018,49(3): 173.
[5] QIU Nian-wei,WANG Xiu-shun,YANG Fa-bin,et al(邱念伟,王修顺,杨发斌,等). Chinese Bulletin of Botany(植物学报),2016,51(5): 667.
[6] GU Dong-dong,WANG Wan-zhang,HU Jian-dong,et al(古冬冬,王万章,胡建东,等). Transactions of the Chinese Society of Agricultural Engineering(农业工程学报),2015,31(S2): 179.
[7] Qi Haixia,Zhu Bingyu,Kong Lingxi,et al. Applied Science-Basel,2020,10(7): 2259.
[8] DONG Zhe,YANG Wu-de,ZHANG Mei-jun,et al(董 哲,杨武德,张美俊,等). Crops(作物杂志),2019,190(3): 132.
[9] Li Dong,Chen Jingming,Zhang Xiao,et al. Remote Sensing of Environment,2020,248: 111985.
[10] Berger Katja,Atzberger Clement,Danner Martin,et al. Remote Sensing, 2018, 10(1): 85.
[11] LEI Xiang-xiang,ZHAO Jing,LIU Hou-cheng,et al(雷祥祥,赵 静, 刘厚诚, 等). Spectroscopy and Spectral Analysis(光谱学与光谱分析),2019,39(10): 3256.
[12] LÜ Jie,WANG Kang-ning,LI Chong-gui,et al(吕 杰,汪康宁,李崇贵,等). Journal of China University of Mining & Technology(中国矿业大学学报),2016,45(2): 405.
[13] Verrelst Jochem,Dethier Sara,Rivera Juan-Pablo, et al. IEEE Geoscience and Remote Sensing Letters, 2016, 13(7): 1012.
[14] Feret J B, Gitelson A A, Noble S D, et al. Remote Sensing of Environment, 2017, 193: 204.
[15] CHENG Jie-hong,CHEN Zheng-guang,ZHANG Qing-hua(程介虹,陈争光,张庆华). Journal of Agricultural Science and Technology(中国农业科技导报),2020,22(1): 162.