Soil spectral library of the ‘Chimiometrie 2006’ challenge. The database contains absorbance spectra of dried and sieved soil samples measured between 1100 nm and 2498 nm at 2 nm interval. The soil samples come from agricultural fields collected from all over the Walloon region in Belgium. Three parameters are associated with the spectral library: Nt (Total Nitrogen in g/Kg of dry soil), CEC (Cation Exchange Capacity in meq/100 g of dry soil) and Ciso (Carbon in g/100 g of dry soil). Carbon content has been measured following the ISO14235 method.
data(NIRsoil)A data.frame of 825 observations and 5 variables (where the spectral data is embedded in one variable NIRSoil$spc).
The dataset includes 618 training and 207 test samples with 5 variables: Nt (Total Nitrogen), Ciso (Carbon),
CEC (Cation Exchange Capacity), train (vector of 0,1 indicating training (1) and validation (0) samples)
and spc (a matrix with absorbance NIR data and band positions as colnames).
Nt, Ciso and CEC have respectively 22 %, 11 % and 46 % of the observations with missing values.
Fernandez Pierna, J.A., and Dardenne, P., 2008. Soil parameter quantification by NIRS as a Chemometric challenge at 'Chimiometrie 2006'. Chemometrics and Intelligent Laboratory Systems 91, 94-98.