Chinese Journal of Agrometeorology ›› 2017, Vol. 38 ›› Issue (03): 172-180.doi: 10.3969/j.issn.1000-6362.2017.03.005

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Effects of Silicon Supply on Reflectance Spectroscopy Characteristics of Rice Canopy under Elevated UV-B Radiation

ZHU Huai-wei ,LOU Yun-sheng ,SHI Yi-fan ,ZHANG Yi-wei ,ZHAO Si-di   

  1. 1.Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Science and Technology, Nanjing 210044, China; 2. Jiangsu Key Laboratory of Agricultural Meteorology, Nanjing University of Information Science and Technology, Nanjing 210044
  • Received:2016-08-16 Online:2017-03-20 Published:2017-03-13

Abstract: A field experiment was conducted to observe the canopy spectra of rice by using ASD FieldSpec HandHeld spectrometer on typical sunny days and analyze the characteristics of red edge parameters by calculating the first derivative spectrum at tillering, jointing, heading and grain-filling stages under the conditions of elevated UV-B radiation and silicon supply. The experiment was designed with two UV-B radiation levels, i.e. ambient UV-B (ambient, A) and elevated UV-B (elevated by 20%, E);with two silicon supply levels, i.e. control and +Si (200kgSiO2ha-1 as sodium silicate). The results indicated that LAI (leaf area index) and chlorophyll content (value of SPAD) were decreased under elevated UV-B radiation, but silicon supply increased and could alleviate the depressive effect of elevated UV-B radiation on rice growth. The differences of rice canopy spectra were mainly reflected in near-infrared band under each treatment, the reflectance of near-infrared band was decreased under elevated UV-B radiation, but increased by silicon application. The red edge position showed blue shift under elevated UV-B radiation and red shift by silicon application. The rice red edge position, red edge amplitude and red edge area showed a trend with an increase firstly and then a decrease, and reached the maximum at jointing stage.

Key words: Elevated UV-B radiation, Silicon supply, Rice, Spectrum analysis, Red edge