Impact of forest trees on the soil reflectance and their relation of soil oxides in Sherawa village, Erbil government- Iraq

Abstract

Soil reflectance spectroscopy has become a pioneering technique for quantifying soil properties that provide data for soil classification and digital soil mapping studies. This work was conducted with the aim to analyze the spatial variability of soil spectrometric properties between surface and subsurface soil under three land use patterns namely; pine, barren land and oak in Sherawa village, northeast Iraq. Soil samples were collected from the three land types at two depths: surface soil at 0–15 cm and subsurface soil at 15–30 cm in duplicates totaling 6 collected soil samples. The elemental composition and mineral phases of soils were determined by X-ray fluorescent XRF and X-ray diffraction (XRD) respectively for qualitative and quantitative characterization. Magnesium oxide (MgO) was highest detected concentration in the surface soil layer reaching 34.16%, 36.75%, and 33.63%, respectively for pine, barren land and oak compared to 41.57%, 38.54%, 33.94% of the respective concentration in the subsurface soil layer samples of pine, barren and oak. Whereas, calcium and iron were the lowest percentages of pine in the surface and subsurface soil layer samples by (2.19%, 4.85%, 3.39%, and 4.55%, respectively). At the same time as, the percentages of oak in the surface and subsurface soil layer samples were (2.24%, 4%, 2.99% and 4.93%, respectively).The results indicate that the use of spectrometric analysis of soils in the field or in the laboratory can positively enhance soil characterization and typification surveys. Moreover, the influence of the silicates near 1400 nm by Al or Mg-OH and OH group were very apparent in the SWIR spectral regions of oak and pine in the subsurface soil. The results also showed the differences in soil color and reflectance between surface soil samples and subsurface surface soil for all site locations. Further studies are proceeding for more investigation at larger scale concerning analyzing the spatial variability of soil spectrometric properties with depth under different land use patterns..

Keywords

• geochemical characterization
• spectral reflection
• vegetation cover
• soil color
• iron oxide