海南橡胶园砖红壤光谱反射特征分析

Spectral reflectance characteristics of laterite for rubber plantation in Hainan Island

【目的】了解海南橡胶园砖红壤的光谱反射特性,为海南胶园土壤分类提供光谱特征的分类指标。【方法】采用ASD Field Spec3高光谱仪采集土壤光谱反射率,对土壤样品进行室内分析,并在此基础上利用经典统计学方法对海南胶园砖红壤光谱反射特性进行分析。【结果】海南橡胶园不同母质发育的砖红壤反射率光谱曲线走势相似,除加来农场只在1900 nm附近出现微弱水分吸收谷外,其余在1400、1900和2200 nm附近光谱曲线均出现明显的吸收谷。但不同土壤类型,光谱反射率强度不同且一些特征吸收带出现的位置和表现的相对强度也不同;胶园土壤中有机质和铁离子的含量共同影响着同种母质发育的不同土壤类型的光谱特征,海南土壤中普遍富含铁而有机质含量少,一般铁对光谱的贡献要大于有机质;不同母质发育的砖红壤光谱特征有很大差异,玄武岩发育成的砖红壤光谱特征最特别,反射率始终最小,且只在1900 nm附近出现微弱水分吸收谷,土壤类型最易鉴别;通过对光谱聚类分析对橡胶园砖红壤进行简单的分类,结果显示所得分类土壤之间光谱反射率存在显著差异(P<0.05)。【结论】不同类型土壤的反射光谱曲线存在一定的规律性,且随着土壤母质、土壤中的有机质含量及铁离子含量的不同而表现一定的光谱特征差异,因此土壤反射光谱可作为土壤分类的一个指标。

[Objective] In order to supply classification indicators of soil spectrum for the classification of soil in rubber plantation, the spectral reflection characteristics of latosol in rubber plantation were analyzed. 【Method 】By the methods of collecting soil spectral reflectance using ACD and analyzing indoor,the spectral reflection characteristics were analyzed based on soil nutrition content and soil spectral reflection. 【Result】The reflectivity spectrum curves of laterite developed from different parent materials in Hainan rubber plantation presented to be similar. There was obvious absorption valley at 1400, 1900 and 2200 nm, except the curve of Jialai farm in which the moisture absorption valley only appeared at 1900 nm. The intensity of spectral reflectance and the position of some characteristic absorption bands were different among different soil types. The spectral characteristics of different soil types developed from the same parent material were affected by the content of soil organic matter and the content of iron ion. Generally speaking, soil in Hainan is rich in iron but poor in organic matter. Iron contributed more to spectrum than organic matter. There were significant differences in spectral characteristics among laterite developed from different parent material. The spectral features of laterite developed from basalt was the most special,which had the minimum reflectivity and the faint moisture absorption valley only appeared near 1900 nm, therefore it was the soil type which was most easily to identify.Based on spectral clustering analysis for plantations laterite simple classification,the analysis of variance showed that there were extremely significant differences among different soil classifications P0.05. 【 Conclusion 】 Some certain regularities exist in the spectral reflectance curves of different soil types,and the spectral reflection characteristics change according to the soil parent material,the content of soil organic matter and the content of soil iron ions. So the soil spectral reflectance can be used as an indirect indicator of soil classification.