Predicting Soil Salinity Based on Spectral Symmetry under Wet Soil Condition
LIU Ya1, 2, PAN Xian-zhang1*, WANG Chang-kun1, 2, LI Yan-li1, 2, SHI Rong-jie1, 2, ZHOU Rui3, XIE Xian-li1
1. Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China 2. University of Chinese Academy of Sciences, Beijing 100049, China 3. Nanjing Branch of the Chinese Academy of Sciences, Nanjing 210008, China
Abstract：There has been a growing interest in using spectral reflectance as a rapid and inexpensive tool for soil salinity monitoring in recent years. However, since soil moisture often exerts a tremendous influence on soil reflectance, the monitoring accuracy under various moisture conditions cannot fully satisfy the requirements of agricultural practice. In the present paper, a linear model was built to relate the spectral symmetry in the band of 1 370～1 610 nm with the salt content and moisture content of the saline soil based on regularly measured data of reflectance, soil moisture and salt content of the surface of 5 soil columns during the simulated evaporation process in laboratory. The results showed that the model was good with r greater than 0.8. By inversing the model, soil salt content then was predicted after moisture content was determined. The results showed that the prediction accuracy was acceptable with a root mean square error (RMSE) of 2.059 g·kg-1 and an r of 0.656. The results demonstrated the feasibility of using spectral symmetry to predict soil salt content under various moisture conditions.
Key words：Soil salinity;Wet condition;Spectral symmetry;Soil salt content;Prediction
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