Proceedings Article | 2 February 2006
KEYWORDS: Soil science, Near infrared, Calibration, Near infrared spectroscopy, Statistical analysis, Spectroscopy, Principal component analysis, Magnesium, Absorbance, Reflectivity
Near-infrared spectroscopy is a rapid and nondestructive technique that has the ability to analyze many constituents at the same time and has been used to quantify various soil properties. The objective of this study was to analyze NIR spectroscopy potential to estimate N, P, K, OM and pH content in a loamy mixed soil. 165 soil samples were taken from the field, 135 samples spectra were used during the calibration and validation stage, and 30 sample spectra were used for
the prediction of N, P, K, OM and pH content. Principal Component Analysis/Partial Least Square (PCA/PLS) was used as multivariate analysis technique to correlate wavelength information with each constituent concentration. The r between measured and predicted values of N, OM and pH was 0.93, 0.93 and 0.91, as well as SEP, 3.28, 0.06 and 0.07, respectively, demonstrated that NIRS method has potential to predict accurately these constituents in soil. Unfortunately, statistics between measured and predicted P and K with r, 0.47 and 0.68, and SEP, 33.70 and 26.54, respectively,
demonstrated a poorly for P and a less successfully K prediction. The result also shows that NIR could be a good tool to be combined with precision farming application.
