摘要
本文研究了我国南方山地丘陵的砖红壤、红壤、黄壤、水稻土和紫色土等的光谱特征,对这些土壤的360—2500nm光谱反射率进行了定量分析,从心土层土壤光谱反射率中选出10个光谱指标,能有效地区分我国南方山地丘陵的主要土壤类型,它可作为土壤发生分类研究的光谱定量指标。
A wide range of natural soils in southern China were collected to study the characteristic variation and to develop a quantitative approch of soil spectral reflectance which are related to soil classification and some soil properties. A total of 81 soil sampleS was collected from A or B horizor in 42 soil profiles which involve five main soil great groups,i.e,latosol,red earth,yellow earth,paddy soil and purplish soil.The reflectance of air-dried soils over range of 0.36—2.5μm wavelength by using a HIACTHI 340 model spectrophotometer in the liboratory.The analytic results of characteristic vatiations in the refectance of the soils demonstratedthat soil type and parent material of natural soils have significiant effect on the variations in the reflectance of the soils.Two distinct reflectance curve patterns were identified according to curve shape and character of spectral absorption bands.The first pattern exhibited a low reflectance with weak absorption bands at 1.4,1.9 and 2.2μm,including latosols and red earths derivedfrom basalts,purplish soils from purplish sandstones and some paddy soils developed from basaltic soils;and the second pattem had a higher reflectance and strong absorption bands at 1.4,1.9 and 2.2 μm,including latosol red earths and yellow earths derired from granites,tuff etc.and the paddy soils.All of soils except purple soil showed stronger absorption bands in the range of 0.8 to 1.1μm,and these bands are related with allitic enrichment and iron oxide content which may directly affect soil refetrance.However,the reflectance of purple soil is influenced by some special properties of parant material,and has been fount to exhibit two characteristic variations:stronger reflectance bands at 1.0 μm and continual reflectance bands from 2.3 to 2.41 μm.The quantitative approch of the reflectance characteristic variations of B horizon soils were used to explain various types of soils in southern China.At first characteristic variations were chosen subjcotively and extracted by mathematic method,and then many sorted stepwise discriminant analysis were conducted. The result have demonstrated that six groups of discriminant equations could be established only by 10 spectral variables.chosen from the reflectance as fllows:f_i(x)=lnqi+C_(0i)+sum from k=1 to 10 X_k·C_(ki) (i=1,2,……6)Where q_i,C_(οi) and C_(ki) are coefficients of the discriminant equations.Ten variables are:reflectances at 0.78,1.0,1.66 and 2.49μm;differences between 0.65 and 0.63μm;0.77 and 0.79 μm;average of the overall refectances;intensity of the absorption valley at 1.4,1.9 and 2.2μm.The discriminant equations could differentiate six soil groups availably.The vatiables could be used as quantitative indices in the research of soil gensis and classification.
出处
《土壤学报》
CAS
CSCD
北大核心
1991年第2期177-185,共9页
Acta Pedologica Sinica
