黑土反射光谱特征影响因素分析

Study on the Main Influencing Factors of Black Soil Spectral Characteristics

以黑土高光谱反射率为研究对象,运用去包络线处理、光谱角度/特征匹配方法,分析黑土反射光谱特征主要影响因素。结果表明,成土母质决定了土壤反射光谱的基本特征;有机质是小于1000nm范围黑土反射光谱特征的决定因素,同时由于有机质与土壤水分、机械组成的相关关系,间接影响着大于1000nm的波谱范围;土壤光谱反射率随含水量的变化过程可以用三次方程模型进行定量描述;铁对黑土反射光谱特性影响较小;粗糙度主要影响土壤反射率的大小;秸秆覆盖对土壤反射率大小与形状特征的影响均较大;不同耕作措施土壤反射率大小依次为免耕、翻耕、组合、少耕、旋松。

To develop soil properties quick measuring methods,promote the development of quantitatively remote sensing studies relating to terrestrial ecosystem,and deepen the application of remote sensing in agriculture,the hyperspectral reflectance of black soil in Songnen Plain,northeast China,was analyzed with spectral analysis methods （continuum removal,spectral angle match and spectral feature fitting） and statistic methods to discover the reflectance spectral characteristics and its influencing factors. The results are as follows：the soil parent material determines the basic characteristics of reflectance of the black soil,which is the mixture of montmorillonite and illite,and consistent with mineral analysis result. Organic matter is the main factor determining the curve shape of black soil reflectance in the region shorter than 1 000 nm,and indirectly influencing the reflectance in the region longer than 1 000 nm because of the correlation with soil moisture and mechanical composition. The varying process of soil reflectance with changing soil moisture can be quantitatively described with cubic equation,and moisture mainly changes the reflectance value but not the curve shape. Black soil reflectance is not influenced significantly by Fe,which is different from soils of south China. Roughness mainly impacts on the soil reflectance value but not the shape feature. The spectral feature of straw reflectance is remarkably different to that of black soil,and impacts on both the value and curve shape of black soil reflectance. Different soil tillage measurements result in different moisture holding ability and the amount of straw for different farm fields,and influence the reflectance further,with the order of soil reflectance from high to low is：no tillage,moldboard tillage,combination tillage,reduced tillage,and rotary tillage.