红外光谱法作为一种新的研究手段已经广泛应用于土壤分析,由其检测区域和手段的不同又可分为多种光谱类型.本研究以第四纪黄土为例,系统地比较了近红外区和中红外区反射光谱和光声光谱的吸收特征及其差异.结果表明,中红外光谱比近红外光谱的信息更为丰富,且中红外光谱与样品中物质的特征吸收关系更加密切,从而更有利于土壤定性与定量分析. 土壤的反射光谱和光声光谱表现出了明显不同的特征,在近红外区,反射光谱和光声光谱吸收明显不同,而在中红外区,反射光谱和光声光谱具有相对应的吸收,但相对吸收强度明显不同,且吸收峰的位置也发生改变,尤其在1000～2000 cm-1谱区,反射光谱相互干扰很强,而光声光谱的吸收特征更为明显.在黄土的分类鉴别上,反射光谱优于光声光谱.红外反射光谱和光声光谱在不同波段下具有不同的吸收灵敏度,在土壤定性与定量分析中各白都将具有其明显的优势.%Infrared spectroscopy has been applied in soil analysis as a new method for years, and various infrared techniques have been identified with regard to the wavelength and signal detector. The infrared spectra of loess soil were characterized using infrared photoacoustic and reflectance spectroscopy in near- and mid-infrared region, and more closely relationship were found between the absorptions and soil attributes in mid-infrared region, which benefited the soil quantitative and qualitative analyses. The characteristics of infrared reflectance spectra significantly differed from infrared photoacoustic spectra; in mid-infrared region, there were counterpart absorptions in reflectance and photoacoustic spectra, but the relative intensity of absorption bands were significantly different, and the locations of some bands shifted, especially in the wave-number range of 1 000-2 000 cm'. In the classification of loess, reflectance spectroscopy seemed better than photoacoutic spectroscopy. In conclusion, the sensibilities of infrared reflectance and photoacoustic spectroscopy in different wavelength varied, and infrared photoacoutic spectroscopy indicated unique advantage in the quantitative and qualitative analysis for opaque and heterogeneous soil samples.
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