Abstract:

【Objective】The objective of the study is to explore and establish the monitoring approach of purple soil microelements based on near infrared spectroscopy technology. 【Method】There were 168 samples of background soil of main sweet orange orchards in Three Gorges Reservoir Area were collected. After the sample processing, 100 samples were selected as calibration samples randomly, others for test samples. The quantity of near infrared spectrum and total Fe, Mn, Zn content of purple soil were determined. By using the optimum spectrum pretreatment and partial least square method(PLS) along with internal cross- validation the calibration models were established, and the model accuracy was tested.【Result】The best spectrum pretreatment for prediction of total Fe, Mn, Zn contents of purple soil is standardization of variables by using near infrared spectroscopy. The calibration models of Fe, Mn, Zn concentration of purple soil established by using the spectrum pretreatment, PLS and internal cross-validation, the precisions under 95% confidence interval were 92.65%, 95.59% and 95.59%, respectively.【Conclusion】It has a certain feasibility by using the near-infrared spectroscopy to predict total Fe, Mn, Zn concentrations of purple soil.

Key words: citrus orchard, purple soil, Fe, Mn, Zn concentration, monitoring models, near infrared spectroscopy (nir- spectroscopy)