Estimating purple-soil moisture content using Vis-NIR spectroscopy  

作　　者：GOU Yu WEI Jie LI Jin-lin HAN Chen TU Qing-yan LIU Chun-hong 

机构地区：[1]School of Geography and Tourism Science,Chongqing Normal University,Chongqing 401331,China [2]Chongqing Key Laboratory of Surface Process and Environment Remote Sensing in the Three Gorges Reservoir Area,Chongqing 401331,China

出　　处：《Journal of Mountain Science》2020年第9期2214-2223,共10页山地科学学报（英文）

基　　金：funded by Chongqing Talent Program(CQYC201905009);Chongqing Education Commission(KJZD-K201800502,KJQN201800531);Science Fund for Distinguished Young Scholars of Chongqing(cstc2019jcyjjq X0025)。

摘　　要：Soil moisture is essential for plant growth in terrestrial ecosystems.This study investigated the visible-near infrared(Vis-NIR)spectra of three subgroups of purple soils(calcareous,neutral,and acidic)from western Chongqing,China,containing different water contents.The relationship between soil moisture and spectral reflectivity(R)was analyzed using four spectral transformations,and estimation models were established for estimating the soil moisture content(SMC)of purple soil based on stepwise multiple linear regression(SMLR)and partial least squares regression(PLSR).We found that soil spectra were similar for different moisture contents,with reflectivity decreasing with increasing moisture content and following the order neutral>calcareous>acidic purple soil(at constant moisture content).Three of the four spectral transformations can highlight spectral sensitivity to SMC and significantly improve the correlation between the reflectance spectra and SMC.SMLR and PLSRmethods provide similar prediction accuracy.The PLSR-based model using a first-order reflectivity differential(R?)is more effective for estimating the SMC,and gave coefficient of determination(v2),root mean square errors of validation(RMSEV),and ratio of performance to inter-quartile distance(RPIQ)values of 0.946,1.347,and 6.328,respectively,for the calcareous purple soil,and 0.944,1.818,and 6.569,respectively,for the acidic purple soil.For neutral purple soil,the best prediction was obtained using the SMLR method with R?transformation,yieldingv2,RMSEV and RPIQ values of 0.973,0.888 and 8.791,respectively.In general,PLSR is more suitable than SMLR for estimating the SMC of purple soil.

关 键 词：Purple soil Soil moisture Vis-NIR spectroscopy Stepwise multiple linear regression Partial least squares regression 

分 类 号：S152.7[农业科学—土壤学]