The prediction of C and N content and their potential mineralisation in heterogeneous soil samples using Vis–NIRspectroscopy and comparative methods

The development of a rapid, accurate and cost-effective method for the prediction of constituents related to soil nitrogen (N) supply is considered important. The potential of using visible (Vis) and near infrared reflectance (NIR) spectroscopy (400–2500 nm) as such a method was investigated. Vis–NIR calibrations were performed for organic carbon (Corg) and total N (Ntot) content and their potential mineralisation using 80 grassland soil samples of rather heterogeneous origin. Prediction accuracy was tested using a ‘take-out-four’ validation strategy (48 samples).Within investigated variables a ratio of standard deviation of reference data to standard error of bias corrected prediction (RPD) within 1.7 (r2 = 0.65) and 2.7 (r2 = 0.87) were achieved. Apparent differences........