Title
Application of Spectrally Derived Soil Type as Ancillary Data to Improve the Estimation of Soil Organic Carbon by Using the Chinese Soil Vis-NIR Spectral Library.
Abstract
Ancillary data, such as soil type, may improve the visible and near-infrared (vis-NIR) estimation of soil organic carbon (SOC); however, they require data collection or expert knowledge. The application of a national soil spectral library to local SOC estimations usually requires soil type information, because the relationships between vis-NIR spectra and SOC from different populations may vary. Using 515 samples of five soil types (genetic soil classification of China, GSCC) from the Chinese soil spectral library (CSSL), we compared three strategies in the vis-NIR estimation of SOC. Different regression models were calibrated using the entire dataset (Strategy I, without using soil type as ancillary data) and the subsets stratified by soil type from CSSL as ancillary data (strategies II and III). In Strategy II, the subsets were stratified by soil type from the CSSL for validation. In Strategy III, the subsets were stratified by spectrally derived soil type for validation. The results showed that 86.72% of the samples were successfully discriminated for the soil types by using the vis-NIR spectra. The coefficients of determination in the prediction (R-p(2)) of SOC estimation by strategies I, II, and III were 0.74, 0.83, and 0.82, respectively. The stratified calibration strategies (strategies II and III) improved the vis-NIR estimation of SOC. The misclassification of the soil type in the application of Strategy III slightly affected the SOC estimations. Nevertheless, this strategy is inexpensive and beneficial when expert knowledge on soil classification is lacking. We concluded that vis-NIR spectroscopy could be applied to distinguish some soil types in terms of GSCC, which further provided essential and easily accessible ancillary data for the application of stratified calibration strategies in the vis-NIR estimation of SOC.
Year
DOI
Venue
2018
10.3390/rs10111747
REMOTE SENSING
Keywords
Field
DocType
soil spectral library,vis-NIR spectroscopy,soil organic carbon,soil type
Ancillary data,Remote sensing,Soil type,Soil carbon,Geology
Journal
Volume
Issue
ISSN
10
11
2072-4292
Citations 
PageRank 
References 
2
0.40
5
Authors
9
Name
Order
Citations
PageRank
Yi Liu161.94
Zhou Shi21112.06
Ganlin Zhang320.40
Yiyun Chen4117.68
Shuo Li56113.39
Yongshen Hong620.40
tiezhu shi74410.40
junjie wang8235.23
Yaolin Liu99725.42