Estimation of some chemical properties of an agricultural soil by spectroradiometric measurements

The contents of nitrogen and organic carbon in an agricultural soil were analyzed using reflectance measurements (n = 52) performed with an ASD FieldSpec-II spectroradiometer. For parameter prediction, empirical models based on partial least squares (PLS) regression were defined from the measured reflectance spectra (0.4 to 2.4 mu m). Here, reliable estimates were obtained for nitrogen content, but prediction accuracy was only moderate for organic carbon. For nitrogen, the real spatial pattern of within-field variability was reproduced with high accuracy. The results indicate the potential of this method as a quick screening tool for the spatial assessment of nitrogen and organic carbon, and therefore an appropriate alternative to time- and cost-intensive chemical analysis in the laboratory.