基于可见光光谱分析的土壤参数分析(英文)

Evaluating soil parameters with visible spectroscopy

利用光谱分析技术 ,进行了农田原始状态土壤样品的可见光光谱与土壤参数之间的相关、回归分析。土壤样品采集于一块水分较低的玉米地和一块水分较高的牧草地 ,所分析的土壤参数有土壤水分、土壤有机质含量、土壤硝态氮含量、土壤电导率以及土壤 p H值 ,土样的可见光光谱由精密分光光度计测量。分析结果显示 ,有效的光谱特性值为反射光谱的一次微分 ,所有 5个土壤参数都可以利用土样的可见光光谱特性进行分析和检测。对于土壤水分、土壤有机质含量、土壤电导率以及土壤 p H值 ,线性模型是有效的 ;而对于土壤硝态氮含量 ,则需要利用多元指数模型进行分析或检测。

Using spectroscopic techniques, correlation analysis and regression were conducted between soil parameters and visible reflectance spectra of raw soil samples. The samples were collected in a cornfield with lower moisture content and a forage field with higher moisture content. Five soil parameters, soil moisture, SOM, NO 3-N, EC and pH, were analyzed by conventional method in a laboratory. Visible reflectance spectra of the samples were measured by a spectrophotometer. The spectral variable used was the first derivative of visible reflectance. Results showed that all five soil parameters could be evaluated by visible reflectance. In the cornfield with lower moisture (<30% db), a single linear regression model was available for moisture estimation, and a multiple exponential model was recommended to evaluate NO 3-N. However, it failed to establish the evaluating model of SOM because of its small variation, and it was difficult to obtain the estimation model of EC and pH because of lower moisture content. In the forage field with higher moisture (>70% db), a multinomial model with single variable was better for moisture estimation, and a single linear model and two multiple linear models were recommended to evaluate SOM, EC and pH respectively. For NO 3-N, a multiple exponential model was also recommended. It would be necessary to study the correlation between visible reflectance and soil parameters of raw soil samples with middle moisture (30%～70% db).