Determination of Some Soil Properties with Near-infrared Reflectance Spectroscopy

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 soil classification. There is a wide variety of analysis methods to determine 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 (R^2) between reflectance by NIRS and soil analyses were obtained as follows: clay R^2=0.59, silt R^2=0.59, sand R^2=0.56, field capacity R^2=0.74, wilting point R^2=0.67, bulk density R^2=0.70, pH (1:1, soil: water) R^2=0.55, pH (1:1 soil: KCl) R2=0.51, lime R2=0.90, organic matter R^2=0.57, CEC (cation exchange capacity) R^2=0.90, exchangeable Ca+Mg R^2=0.64, exchangeable K R^2=0.66, exchangeable Na R^2=0.58 and COLE (coefficient of linear extensibility) R^2=0.50.