Determination of Some Soil Properties with Near-infrared Reflectance Spectroscopy

Abstract

At the modern soil classification system, it is necessary to determine the soil parameters, which cannot be identified in situ, under the laboratory conditions. The obtained data can be validated and interpreted by soil formation hypotheses. Obtained parameters can be used as a fundamental mechanism to interpret the soil formation processes and the soilclassification. There is a wide variety of analysis methods to determine the physical and chemical properties of soils. Although time-consuming and expensive methods have been used to determine of these features, some studies on some alternative methods such as NIRS (near-infrared reflectance spectroscopy) have been carried out recently. NIRS method includes some features such as physically harmless analyses of the material, the rapidity, repeatability, allowing simultaneously analyses of more than one parameter and cost-effectiveness. This study reveals the relations between some soil properties and NIRS results of soil samples from horizons of the identified common great groups includes Isparta, Burdur, Antalya, Denizli and Afyonkarahisar provinces in Turkey. On the other hand, these data will provide a contribution to the data library for this area. The following coefficient of determination values (R2) between reflectance by NIRS and soil analyses were obtained as follows: clay R2=0.59, silt R2=0.59, sand R2=0.56, field capacity R2=0.74, wilting point R2=0.67, bulk density R2=0.70, pH (1:1, soil: water) R2=0.55, pH (1:1 soil: KCl) R2=0.51, lime R2=0.90, organic matter R2=0.57, CEC (cation exchange capacity) R2=0.90, exchangeable Ca+Mg R2=0.64, exchangeable K R2=0.66, exchangeable Na R2=0.58 and COLE (coefficient of linear extensibility) R2=0.50.

Keywords

• near-infrared reflectance spectroscopy (nirs)
• soil properties
• spectral library
• yakın kızılötesi yansıma spektroskopisi (nirs); toprak özellikleri; spektral kütüphane; spektroradyometre