title: [Spectral inversion models for prediction of red soil total nitrogen content in subtropical region (Fuzhou)].
abstract: The present paper studied the hyperspectral response characteristics of red soil, with 135 soil samples in Fuzhou city. After monitoring the hypersectral reflection of soil samples with ASD (analytical spectral device) and total nitrogen contents with Vario MAX (for nitrogen and carbon analysis), the paper gained the spectral reflection data between 350-2 500 nm (resolution is 1 nm) and soil total nitrogen contents. Then the paper treated the hyperspectral reflection data with 5 mathematic conversions such as first derivative and second derivative conversions of original reflection, reciprocal logarithmic conversion and its first derivative and second derivative conversion in advance. The next step was to calculate the correlation coefficient of soil nitrogen and the above spectral information, and select the sensitive spectral bands according to the highest correlation coefficient. Finally, by designing different proportions of modeling and validation sample data sets, the paper established the quantitative linear models between soil total nitrogen contents and hyperspectral reflection and its 5 converted information, the final optimal mathematic model between soil nitrogen and hyperspectral information was significantly determined. Results showed that 634-688, 872, 873, 1 414 and 1 415 nm were the main sensitive bands for soil total nitrogen, and Y = 5.384X(664) -1.039 (Y represents soil nitrogen content, X664 is the soil spectral absorbance value at 664 nm) was the optimal soil total nitrogen predicting model (in the model, the determination coefficients R2 and the RMSE of total nitrogen were 0.616 and 0.422 mg X g(-1), the inspection coefficient R2 and the RMSE were 0.608 and 0.546 mg x g(-1) respectively). The model can be used to rapidly monitor soil total nitrogen with hyperspectral reflection in Fuzhou area.
authors.affiliation: College of Environmental Science and Engineering, Fujian Normal University, Fuzhou 350007, China. wmz0595@163.com
authors.forename: Ming-Zhu
authors.initials: MZ
authors.lastname: Wu
authors.affiliation: College of Environmental Science and Engineering, Fujian Normal University, Fuzhou 350007, China.
authors.forename: Xiao-Mei
authors.initials: XM
authors.lastname: Li
authors.affiliation: College of Geographical Sciences, Fujian Normal University, Fuzhou 350007, China.
authors.forename: Jin-Ming
authors.initials: JM
authors.lastname: Sha