A LUCAS?based mid?infrared soil spectral library: Its usefulness for soil survey and precision agriculture#

Background Mid-infrared spectroscopy (MIRS) is commonly recognized as a rapid and high throughput measurement technology for numerous soil properties, given that appropriate prediction models are calibrated. Soil spectral libraries (SSL) may reduce effort costs MIRS practical application. Aims To calibrate MIR-SSL-based properties to test their applicability independent sample sets at regional scale (e.g., survey) field (i.e., precision agriculture, PA). Methods Spectra of 1013 arable topsoil samples the European Land Use/Land Cover Area Frame Survey 2009 (LUCAS) from Belgium, Netherlands, Luxembourg, Germany formed basis MIR-SSL. Leave-one-out cross-validation (LOOCV) via partial least squares regression served (1) generic including all samples, (2) stratified different parent materials. Test-set validation (TSV) was conducted on campaigns with set Schleswig-Holstein (Germany; n = 385) four individual fields in (n 513). Results Generic LOOCV successfully predicted organic carbon, total nitrogen, sand, silt, clay, carbonate, pH. Calibration available nutrients failed. The TSV successful variables (2.5 ? RPIQ 5.9), except carbonate (RPIQ 0). At scale, highly variable sites parameters. Stratified using material auxiliary improved only occasionally is, single clay carbonate. Conclusions Although MIR-SSL its present state cannot be recommended nutrient management, it provides valuable support survey PA.