Liu Huanjun, Zhang Yuanzhi, Zhang Bai
Northeast Institute of Geography and Agricultural Ecology, Chinese Academy of Sciences, Changchun 130012, China.
Environ Monit Assess. 2009 Jul;154(1-4):147-54. doi: 10.1007/s10661-008-0385-4. Epub 2008 Jun 17.
This paper presents a novel method for estimating black-soil organic matter (SOM) in the black-soil zone of northeast China from hyperspectral reflectance models. Traditional black-soil property measurements are relatively slow, but the pressures of agricultural production and environmental protection require a quick method to collect black-soil organic matter content. SOM estimation using soil hyperspectral reflectance models can meet this requirement, based on the spectral characteristics of black-soil in Northeast China. On the basis of the spectral reflectance and its derivatives, hyperspectral models can be built using correlation analysis and multivariable statistical methods. The concepts of curvature and ratio indices are also applied to compare and test the stability and accuracy of data modeling. The results show that the response of black-soil spectral reflectance from 400-1,100 nm to organic matter content is more marked than that from 1,100-2,500 nm. Specifically, the main response range of black-soil organic matter is between 620-810 nm, with a maximal spectral response at 710 nm. By comparing different models, we found that the normalized first derivate model is optimal for estimating SOM content, with a determination coefficient of 0.93 and root mean squared errors (RMSE) of 0.18%.
本文提出了一种基于高光谱反射模型估算中国东北黑土区黑土有机质（SOM）的新方法。传统的黑土性质测量相对较慢，但农业生产和环境保护的压力要求有一种快速方法来获取黑土有机质含量。利用土壤高光谱反射模型估算SOM能够满足这一要求，其依据是中国东北黑土的光谱特征。基于光谱反射率及其导数，可运用相关分析和多变量统计方法建立高光谱模型。曲率和比值指数的概念也被用于比较和检验数据建模的稳定性和准确性。结果表明，黑土在400 - 1100nm波段的光谱反射率对有机质含量的响应比在1100 - 2500nm波段更为显著。具体而言，黑土有机质的主要响应范围在620 - 810nm之间，在710nm处有最大光谱响应。通过比较不同模型，我们发现归一化一阶导数模型在估算SOM含量方面表现最佳，其决定系数为0.93，均方根误差（RMSE）为0.18%。
