Evaluating the effect of humidity and acidity on the optical characteristic of a soil sample


Imre T. TOLNER 1, Kornél D. SZALAY 2, Ádám Csorba 3, László TOLNER 3, József DEÁKVÁRI 4, Gábor MILICS 1, László FENYVESI 4, Miklós NEMÉNYI 1,


1 University of West Hungary Faculty of Agricultural and Food Science

tolner.imre@mtk.nyme.hu

2 Hungarian Institute of Agricultural Engineering, Outer Agricultural Technical Department of Szent István University, Tessedik Sámuel u. 4., Gödöllő, Hungary,

3 Szent István University, Department of Soil Science and Agrochemistry, Gödöllő, Hungary

4 Hungarian Institute of Agricultural Engineering, Tessedik Sámuel street 4., Gödöllő , Hungary



Summary: Diagnosing soil parameters is important part of agriculture, environment protection, and geology too. Compared to the hyperspectral remote sensing, the conventional methods makes possible to evaluate the topsoil of large areas in fast and economic way. The ASD spectroraimeter of the Hungarian Institute of Agricultural Engineering is capable of gathering spectral information in the wavelength from 350 to 2500 nm. The spectral information referring to soils are usually studied in the upper range of this interval. Detection of soil acidity with remote sensing is not easy because practically we can only analyse the indirect effects of the pH change by measuring the characteristic of the reflected light from the surface of the soil. As a result of the chemical reaction during the pH change new formation of molecules, molecule parts and ions are modifying the reflection parameters of the soil and this alteration can be measured. Through these changing factors we can conclude to the level of the soil acidity. In the following experiment we are examining the reflectance spectrum of one soil sample in laboratory. In order to make various pH levels the soil samples were treated differently with hydrochloric acid. As a result of the treatment the spectrums had modified. The spectral interval referring to the OH group showed significant dislocation. Eliminate the confounding effects of water we used usually completely dried samples in laboratory. In this project, we also examined the samples on air-dried state. In this case the samples contain water, balanced air humidity.

Keywords: hyperspectral technology, soil acidity, humidity