The Detection of Soil Parameters by Portable near Infrared Spectrometer

Soil test is the key-point for formulated fertilization. The traditional chemical analysis methods for estimating soil nutritional parameters were time-consuming. The present aims to use portable acousto-optic tunable filter (AOTF) near-infrared (NIR) spectrometer to measure soil parameters, thus provide basis for field analysis of soil quality. A total of 231 soil samples were collected, Partial least squares (PLS) was used to construct the calibration model between the NIR spectra and the reference values measure by standard chemical methods, including organic matter, pH, ammonium nitrogen, nitric nitrogen, and total kalium content. Results showed that the prediction of organic matter and pH had high correlation (R=0.8745, R=0.8594, respectively), the prediction of ammonium nitrogen and total kalium content were acceptable (SEP%=23.2595%, 10.1516%), and the calibration model for nitric nitrogen had the worst performance. The present study indicated that portable AOTF-NIR spectrometer could be used to measure the nutrient parameters of soil.