Nitrogen vertical distribution by canopy reflectance spectrum in winter wheat

35th International Symposium on Remote Sensing of Environment

地球科学;生态环境科学

Huang, W.J.^1 ; Yang, Q.Y.^1,2 ; Peng, D.L.^1 ; Huang, L.S.^2 ; Zhang, D.Y.^2 ; Yang, G.J.^3

Key Laboratory of Digital Earth Science, Institute of Remote Sensing and Digital Earth, Chinese Academy of Sciences, Beijing 100094, China^1

Key Laboratory of Intelligent Computing and Signal Processing, Ministry of Education, Anhui University, Hefei 230039, Anhui, China^2

Beijing Agriculture Information Technology Research Center, Beijing 100097, China^3

关键词: Bidirectional reflectance;    Canopy reflectance spectra;    Ecosystem productivity;    Layer distributions;    Nitrogen content;    Nitrogen deficiency;    Vertical distributions;    Winter wheat;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/17/1/012051/pdf
DOI  :  10.1088/1755-1315/17/1/012051

学科分类：环境科学（综合）

来源: IOP

【 摘 要 】

Nitrogen is a key factor for plant photosynthesis, ecosystem productivity and leaf respiration. Under the condition of nitrogen deficiency, the crop shows the nitrogen deficiency symptoms in the bottom leaves, while excessive nitrogen will affect the upper layer leaves first. Thus, timely measurement of vertical distribution of foliage nitrogen content is critical for growth diagnosis, crop management and reducing environmental impact. This study presents a method using bi-directional reflectance difference function (BRDF) data to invert foliage nitrogen vertical distribution. We developed upper-layer nitrogen inversion index (ULNI), middle-layer nitrogen inversion index (MLNI) and bottom-layer nitrogen inversion index (BLNI) to reflect foliage nitrogen inversion at upper layer, middle layer and bottom layer, respectively. Both ULNI and MLNI were made by the value of the ratio of Modified Chlorophyll Absorption Ration Index to the second Modified Triangular Vegetation Index (MCARI/MTVI2) referred to as canopy nitrogen inversion index (CNII) in this study at ±40° and ±50°, and at ±30° and ±40° view angles, respectively. The BLNI was composed by the value of nitrogen reflectance index (NRI) at ±20° and ±30° view angles. These results suggest that it is feasible to measure foliage nitrogen vertical-layer distribution in a large scale by remote sensing.