植物生态学报 ›› 2009, Vol. 33 ›› Issue (4): 791-801.DOI: 10.3773/j.issn.1005-264x.2009.04.018

• 研究论文 • 上一篇    下一篇

利用红边面积形状参数估测水稻叶层氮浓度

田永超, 杨杰, 姚霞, 朱艳, 曹卫星*()   

  1. 南京农业大学江苏省信息农业高技术研究重点实验室,南京 210095
  • 收稿日期:2008-12-04 修回日期:2009-03-15 出版日期:2009-12-04 发布日期:2009-07-30
  • 通讯作者: 曹卫星
  • 作者简介:*(caow@njau.edu.cn)
  • 基金资助:
    国家自然科学基金(30571092);国家自然科学基金(30671215);国家“863”计划(2006AA10Z202);国家“863”计划(2006AA10Z271);高校博士点基金(20070307035);国家科技支撑计划项目(2006BAD10A01)

ESTIMATION OF LEAF CANOPY NITROGEN CONCENTRATION WITH RED EDGE AREA SHAPE PARAMETER IN RICE

TIAN Yong-Chao, YANG Jie, YAO Xia, ZHU Yan, CAO Wei-Xing*()   

  1. Jiangsu Key Laboratory for Information Agriculture, Nanjing Agricultural University, Nanjing 210095, China
  • Received:2008-12-04 Revised:2009-03-15 Online:2009-12-04 Published:2009-07-30
  • Contact: CAO Wei-Xing

摘要:

研究红边面积参数与叶层氮素状况的定量关系, 有助于水稻(Oryza sativa)生长信息的实时无损获取及精确追氮管理。该研究基于多年不同施氮水平和不同水稻品种的冠层高光谱数据, 系统分析了水稻的红边区域光谱、面积形状特征及其与叶层氮浓度的定量关系。结果表明, 水稻冠层红边区域微分光谱随不同氮素水平变化出现“三峰”现象, 峰值分别出现在700、720和730 nm附近, 且3个波段的峰值高低发生交替变化; 同时, 以3个峰值波段为中心与x坐标轴组成的微分光谱面积和形状相应发生变化。发现基于两两峰值波段划分所得红边子面积所构成的比值(双峰对称度)、归一化差值(归一化对称度)参数与叶层氮浓度具有密切的定量关系, 可作为估测水稻叶层氮浓度的红边面积形状参数。经曲线拟合和模型检验的结果显示, 双峰对称度DPS (A675-700, A675-755), 即由675~700 nm区域面积与675~755 nm区域面积的比值, 和DPS (A730-755,A675-700) (由730~755 nm区域面积和675~700 nm区域面积的比值)对水稻叶层氮浓度的估测效果最好, 可用于不同水稻品种和生长条件下的叶层氮浓度估测。

关键词: 水稻, 叶层, 红边区域面积, 双峰对称度, 归一化对称度, 氮浓度

Abstract:

Aims Quantifying the relationship between red edge area parameter and canopy leaf nitrogen status is the foundation for real-time and non-destructive monitoring of crop growth status and precision nitrogen fertilization in rice (Oryza sativa). Our objectives were to analyze 1) characteristics of the first-derivative reflectance spectra in red edge area and 2) the quantitative relationship of red edge area shape parameters to canopy leaf nitrogen concentrations, using different nitrogen levels and rice varieties and based on canopy hyper-spectral reflectance of field-grown rice in different years.
Methods Spectrum in the red edge area was significantly affected by different nitrogen levels and different rice varieties, and a “three-peak” feature could be observed with the first derivative spectrum at about 700, 720 and 730 nm. The maximum heights of the three peak bands changed with different nitrogen levels, so sub-areas surrounded by the first derivative spectra curve and x coordinate were formed by dividing the red edge area with the “three-peak band line”. Two random sub-areas were selected to calculate ratio (double peak symmetry, DPS) and normalization (normalized double peak symmetry, NDPS), which were related to canopy leaf nitrogen concentrations.
Important findings DPS based on the ratio of two different red edge sub-areas, and NDPS with normalization of the two different red edge sub-areas were significantly related to leaf canopy nitrogen concentrations in rice. Results of model calibration and validation indicated that DPS (A675-700, A675-755) and NDPS (A675-700, A675-755), ratio and normalized difference of areas in 675-700 to 675-755 nm red edge region, respectively, performed the best in estimating leaf canopy nitrogen concentration. Thus, these two spectral indices were suitable red edge area shape parameters for monitoring leaf canopy nitrogen concentrations in rice.

Key words: Oryza sativa, leaf canopy, red edge area, double peak symmetry, normalized double peak symmetry, nitrogen concentration