Comparison of vis-NIR spectral signatures of soils cultivated with sugarcane (Sacharum sp.) in the Villa Clara province

Abstract

The objective of this research was to compare the spectral signature of two soil types, Cambisol and Vertisol, cultivated with sugarcane in the Villa Clara province, Cuba. The soil samples were collected at two levels: 1) Landscape level of the province (DC), 2) within a field (CE). The vis-NIR spectral signatures were acquired in the laboratory by means of a diode array spectrophotometer covering the wavelength range from 399 to 1697 nm. The results showed that the absorbance spectra of these two soil types can clearly be distinguished, which suggests that the soil type could be derived from the spectra. The light absorbance by the soil varied with wavelength in each soil type in DC and CE. A visual comparison of the spectral shape and the variation between a field and landscape within the same soil group showed some similitude. Around the wavelength of 1400 nm in both soil types the absorbance values increase and consequently decrease again. These characteristics bring a good match of the spectral signatures of DC and CE. In addition, in CE an increasing pattern of soil absorbance was observed as organic matter (OM %) increases. This pattern was observed around 399 nm and 580 nm while for Cambisol and Vertisol respectively.

Keywords

• absorbance
• spectra
• near infrared