Analysis of Soil Chemical Properties of Sand-Based Turfgrass Rootzone using Fourier Transform-Infrared Spectroscopy

To evaluate diffuse reflectance Fourier transform-infrared (DRIFT) in near-infrared (NIR) and mid-infrared (MIR) regions in conjunction with partial least square regression analysis for sand-based turfgrass soils, soil samples were collected from greens 6 to 9 years old, composed of two rootzone mixtures and from two establishment fertilization regimes, at different depths (surface to 7.6 cm in 12 layers). Mid-infrared and NIR spectroscopy resulted in similar calibration accuracy for total organic carbon, total nitrogen, cation exchange capacity, electric conductivity, and pH with R² > 0.80. The modeling process for MIR spectrum was repeated on sample subsets, which were grouped from the original samples based on rootzone mixtures, putting green age, and depth to test the robustness of prediction models. Results of this study suggested that DRIFT-NIR and DRIFT-MIR could be used to predict these properties of sand-based turfgrass soils providing the soil samples are from similar depths.