[NIR spectral analysis for soil textural classification].
Using 25 soil samples with known textural compositions, 2 types of NIR instruments, 3 spectral methods associated with 3 spectrum ranges and 3 sampling intervals, the approach to soil textural classification was investigated. From the results obtained, the following conclusions can be drawn: (1) The chemical information could be identified from the peak of the spectral curves, whereas the slope and intercept of spectral curves concerning soil texture resulted from the physical properties of soil samples. Moreover, the intensity of chemical and physical properties varied in different spectra; (2) The distinguishing ability of NIR was limited, depending on the classification criterion proposed; (3) Being tested with four classifaction criterions, the maximal predicting probability was 72%. In the case of sand < 70% and clay < 40%, the maximum was up to 85%; (4) Either acquiring scatter information from the surface of soil samples or extending spectral bands could improve the predicting probability.
Zeng
Qing-Meng
QM
College of Information and Electrical Engineering, China Agricultural University, Beijing 100083, China. zengqingmeng@yahoo.com.cn
Sun
Yu-Rui
YR
Yan
Hong-Bing
HB