Estimation of soil organic matter in Cambisol soil using vis-NIR spectroscopy

The investigation was developed in the agricultural company “Valley del Yabú” located in Santa Clara, Villa Clara province. The objective was to estimate the soil organic matter content with the use of visible and near infrared (vis-NIR) reflectance spectroscopy technique in Cambisol soil. Soil samples were collected at the landscape level to conform the calibration set and in two specific fields to constitute the validation sets. A portable spectrophotometer was used in the wavelength range from 399 to 1697 nm. Reflectance data were related to soil organic matter using partial least squares regression (PLSR). The model accuracy was determined by means of the determination coefficient (R2). Results showed that the reflectance lectures varied with the wavelength and there was an increment from the visible region (379 - 780 nm), to the near infrared region (780 - 1700 nm). The vis-NIR calibration model accuracy obtained at the landscape level was evaluated of good and very good with R2 values of 0.89 and 0.90 respectively when it was validated in the selected specific fields, which showed the correct estimation of the soil organic matter content.