氧化铁对有机质光谱特性的影响分析

通过分析湖南、浙江和福建三省不同氧化铁和有机质含量共253个土样的光谱数据，研究了氧化铁对有机质光谱特征及定量反演的影响。结果表明：氧化铁的光谱特征波段为600—1400 nm；氧化铁含量小于20 g/kg时对有机质的光谱信息没有影响，含量在20—30 g/kg时，对有机质可见光波段光谱信息的表现有影响，近红外波段的影响不大，含量大于30 g/kg时，氧化铁会掩盖有机质的光谱信息；氧化铁与有机质的比值小于0.726时对有机质的光谱信息没有影响，比值为1.05—2时，对有机质400—1300 nm波段光谱信息的表现有影响，1300—2400 nm波段的影响不大，比值大于2.21时，氧化铁会完全掩盖有机质的光谱信息；氧化铁对有机质的光谱定量反演有影响，随氧化铁含量的增加或氧化铁含量与有机质含量比值的增大，模型的稳定性与预测能力有所降低，但氧化铁含量小于20 g/kg、氧化铁含量与有机质含量比值小于2.0时，氧化铁的影响不明显。

Influence of iron oxide on the spectral characteristics of organic matter

Spectral data of Soil Iron Oxide (SIO) content and Soil Organic Matter (SOM) content in 253 soil samples from Hunan, Zhejiang and Fujian provinces were analyzed to investigate the effect of SIO content on spectral characteristics and quantification by remote sensing inversion of SOM content. Results showed the following: the characteristic wave band of SIO content ranges from 600 nm to 1400 nm; if SIO content <20 g/kg, the Spectral Information (SI) of SOM content would not be affected by that of SIO; 20 g/kg < SIO content <30 g/kg, SI in the visible band of SOM content would be influenced; SIO content > 30 g/kg, SI of SIO would cover up that of SOM content. When the ratio of SIO content to SOM content was less than 0.726, SI of SIO content would not affect that of SOM content; when SIO content/SOM content ranged from 1.05 to 2, HI in the range of 400 nm to 1300 nm band of SOM content would be highly influenced, whereas HI in the range of 1300 nm to 2400 nm would be slightly affected; when SIO content/SOM content ratio was more than 2.21, SI of SOM content would be completely covered by that of SIO content. SIO content affected quantificational remote sensing inversion of SOM. The inversion accuracy and stability of prediction model estimating SOM content decreased with the increase in SIO content or the ratio of SIO content to SOM content. However, SIO content slightly affected quantificational inversion of SOM when SIO content was less than 20 g/kg or SIO content/SOM content was less than 2.0.