Investigation of the possibilities of using NIRS (near infrared spectroscopy) reflection technique in the Çukurova case in defining and mapping soil series

Determining and mapping of the soil series with their phases in the detailed soil survey studies is a time consuming and required highly specialization. Therefore, the aim of this study is to determine the usefulness of NIRS reflection technique in the discriminating of soil series in field due to this technique nowadays has been used in the determination of some soil properties. The reflection values of 531 soil samples taken on a horizon basis to present soil series and major phases of the Çukurova Region were obtained. In order to verify the data, belong to the soil series used in the study, four extensive soil series have been sampled, contents of organic matter, calcium carbonate and textural class were determined and the reflection values of theses soils were compared. Statistical analysis was performed using the PLSR method CV (Cross Validation) and model estimation method. As a result of cross-validation, R2 values between the reflection values and calibration of the soil sample 531 in the whole data set for clay; 0.47 for clay; 0.44 for silt; 0.36 for sand; 0.32 for organic matter; 0.21 for lime was found. In the validation set; clay R2 0.44; silt R2 0.41; sand R2 0.29, organic material R2 0.26; lime R2 was found to be 0.18. It is concluded that NIRS technology was found to fail due to low correlation values in the identification and mapping of soil series and lack of healthy relationships between reflection values and soils. Keywords: Visible-near infrared spectroscopy, soil survey, Cukurova Region