选择单一土类黑土作为研究对象, 并准确调配其不同含水量，实验室测定土壤高光谱反射率，利用光谱分析与统计方法，定量描述了不同含水量黑土反射光谱特征，并建立了黑土含水量反射光谱预测模型。结果表明，随土壤含水量的增加，并达到一定阈值（300 g kg-1），反射率存在过饱和现象，但其倒数对数微分可以有效去除过饱和问题；土壤反射率倒数对数微分对土壤含水量的响应表现出三个变化阶段，导致1 870 nm波段的倒数对数微分也表现为非线性变化，需要利用分段函数进行土壤含水量的光谱精确速测。
To study effect of soil moisture on soil reflection spectrum, Black soil, as a single soil class, was selected as subject for the study. Soil samples were collected and prepared to have different water contents. And then, hyperspectral reflectances of the samples was obtained in lab for analysis, statistics and quantitative description. On such a basis, a reflection spectrum-based model for prediction of soil moisture in black soil was established. Results show that with more water added to a certain threshold (300 g kg-1), the phenomenon of oversaturation would appear with soil reflectance. However, the problem could be solved with its derivative of log-transformed reflectance (DDW), of which the response to soil moisture displayed a 3-phased variation, thus resulting in nonlinear variation of DDW at 1 870 nm. It is, therefore, essential to use piecewise functions to rapidly and accurately predict soil water content with spectral data.
刘 洋,丁 潇,刘焕军,张新乐,曲长祥,胡 文,臧红婷.黑土土壤水分反射光谱特征定量分析与预测[J].土壤学报,2014,51(5):1021-1026. DOI:10.11766/trxb201310300500 Liu Yang, Ding Xiao, Liu Huanjun, Zhang Xinle, Qu Changxiang, Hu Wen, Zhang Hongting. Quantitative analysis of reflectance spectrum of black soil as affected by soil moisture for prediction of soil moisture in black soil[J]. Acta Pedologica Sinica,2014,51(5):1021-1026.复制