土壤学报2025，Vol.62Issue(3)：653-664,12.DOI:10.11766/trxb202404120152
土壤碳氮比的可见-近红外与中红外光谱预测
Prediction of Soil Carbon-to-Nitrogen Ratio Based on Visible-Near Infrared and Mid-Infrared Spectroscopy
摘要
Abstract
[Objective]The soil carbon-to-nitrogen ratio(C/N)reflects not only soil quality but also the nutrient balance of soil carbon and nitrogen elements.Thus,rapid and accurate determination of this ratio and the grade is crucial for guiding real-time scientific fertilization and improvement of soil quality.[Method]This study used visible-near infrared(VNIR)and mid-infrared(MIR)spectroscopic data,along with total organic carbon(TOC),total nitrogen(TN),and C/N data from 501 typical tobacco-corn rotation farmland topsoil samples(0～20 cm)in Guizhou Province for characterization.After processing the spectra with Savitzky-Golay(SG)smoothing and standard normalization,three modeling methods were applied:partial least squares regression(PLSR),random forest(RF),and Cubist.Models for predicting soil C/N were constructed using both direct prediction of C/N and indirect prediction(first predicting TOC and TN,then calculating C/N),and the precision of C/N value and grade predictions was analyzed.[Result]The results revealed that:(1)For C/N value prediction,the optimal prediction strategy was direct prediction using MIR-PLSR,which had a prediction precision(relative standard error,RPD)of 1.20;(2)C/N grade could be accurately predicted,with the optimal strategy being direct prediction using the MIR-PLSR model,achieving a grade determination accuracy of 0.71;(3)The main reasons for the low prediction accuracy of C/N values are twofold.First,the uniform stringent fertilization measures in the tobacco fields have reduced the spatial variation in the carbon and nitrogen content of the plow layer soil,thereby also reducing the spatial variation of C/N(the coefficient of variation is 17.15%,indicating moderate variation).Second,the correlation between C/N and both VNIR and MIR spectra was relatively low.[Conclusion]Therefore,the MIR-PLSR model can be used for direct prediction of C/N grades.关键词
土壤有机碳/碳氮比/偏最小二乘回归/高光谱预测Key words
Soil organic carbon/Carbon-to-nitrogen ratio/Partial least squares regression/Hyperspectral prediction分类
农业科技引用本文复制引用
孔祥麒,高维常,潘文杰,蔡凯,杨静,李德成,郑光辉,曾荣..土壤碳氮比的可见-近红外与中红外光谱预测[J].土壤学报,2025,62(3):653-664,12.基金项目
国家自然科学基金项目(42107322)、中国烟草总公司项目(110202102038)、中国烟草总公司贵州省公司项目(2023XM11)共同资助Supported by the National Natural Science Foundation of China(No.42107322),the Key Research and Development Project of China National Tobacco Corporation(No.110202102038),and the National Tobacco Corporation Project(No.2023XM11) （42107322）
