Abstract: In order to compare the estimation models about the organic matter in desert soil at different levels of human disturbance under the same background,this study took the soil in Fukang City,which is at the north of Tianshan Mountains,as the study object and established the hyperspectral-based soil organic matter (SOM) estimation models for soils in the undisturbed area and in the human-disturbed area respectively using the multiple stepwise regression,partial least squares regression and principal component regression method after 6 spectral transformations of the original spectral reflectance.The correlation between the transformation and the SOM was analyzed using the sensitive bands as the independent variables which had passed the P=0.01 and 0.05 level of significance test.The results indicated as follows:(1) All the correlation coefficients between the original spectral bands and the SOM in both the undisturbed area and human-disturbed area did not pass the 0.01 level of significance test.After removing the samples with the mass fraction being greater than 2%,the correlation coefficients were bigger than those concerning all samples and a portion of the bands had passed the 0.01 level of significance test. (2) Regardless of the method in establishing the SOM estimation model for the full sample size in undisturbed area or in human-disturbed area,the RPD of the models were less than 1.4 which indicated they were not capable of predicting organic content.The first order differential model for all samples in the undisturbed area,and the first order differential multiple stepwise regression model of the reciprocals in the human-disturbed area had the highest precision among all the models with R² being 0.652 and 0.512 respectively.(3) After removing the samples whose mass fraction were greater than 2%,for the undisturbed area the best estimation model was the first order differential multiple stepwise regression model with R² being 0.776,the RMSE being 1.408,and RPD,2.136; for the human-disturbed area,the second-order differential model was optimal with R² being 0.542,the RMSE being 2.261 and RPD,2.087.

Key words: level of human disturbance, desert soil, organic matter, estimation models