Soil Spectral Properties and Their Relationships with Environmental Parameters - Examples from Arid Regions

Abstract

The development of global studies on terrestrial environments has led to a renewed interest in soils. In addition to supporting and nourishing the biomass, soils play a very important interface and buffer function in the ecosystems. For instance, large parts of the carbon, water and gases fluxes are controlled by soils which can be referred as the’ skin’ of terrestrial ecosystems.

Remote sensing techniques are essential in the global approach and links between soil properties and spectral features have been investigated. New instruments currently enable to measure these features with high resolution. In this paper we will first summarise the techniques used to measure soil spectra in the laboratory, in the field and remotely. Then, we will discuss the relationships between the shapes of the spectral reflectance curves observed and the soil composition (organic carbon, iron oxides, and hydrous minerals, particularly). The spectral characteristics of aridic soils and their use as ‘desertification’ indicators will illustrate the potential of imaging spectrometry for the assessment of environmental changes through the detection of soil surface spectral variations. Finally, the example of simulated impact of soils on the remote measurement of vegetation parameters will enable to conclude on the necessity of giving more consideration to soils and their spectral variability.