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以新疆玛纳斯县不同质地土壤(砂壤土、粉粘壤土和粘土)室内光谱反射率作为研究对象,采用包络线去除法对土壤光谱曲线进行处理,与土壤含水量进行相关分析并建立模型。结果表明:不同质地土壤光谱反射率大小依次为:粘土>粉粘壤土>砂壤土;砂壤土、粉粘壤土和粘土分别以田间持水量20.01%,24.10%和30.43%为临界点,在低于该临界点范围内含水量与反射率呈反比,在高于该临界点范围内含水量与反射率呈正比;在1 390～1 623nm波段内,土壤含水量与光谱归一化反射率有较好的负相关,并达到显著水平,所建立的土壤含水量预测模型R2值达到0.8以上,模型平均相对误差为10%。结果表明,建立不同质地土壤含水量光谱预测模型可以较准确反映土壤含水量,其快速、无损、准确的优点,为测定土壤含水量提供了一种新方法。
Taking the indoor spectral reflectance of soil with different textures (sandy loam, silty loam and clay) in Manas County of Xinjiang as the research object, the spectral curve of soil was treated by the envelope removal method, and the soil moisture content was analyzed and the model . The results showed that the spectral reflectance of different texture soils were as follows: clay> silty clay loam> sandy loam; sandy loam, silty clay loam and clay were the critical points of field water content of 20.01%, 24.10% and 30.43% respectively, The water content in the critical point range is inversely proportional to the reflectance, and the water content above the critical point is proportional to the reflectance. In the band of 1 390-1 623 nm, the soil water content is more than that of the normalized spectral reflectance Good negative correlation, and reached a significant level. The soil moisture content prediction model R2 established above 0.8, the average relative error of the model was 10%. The results show that establishing a spectral prediction model of soil moisture content with different textures can accurately reflect the soil moisture content, which is rapid, nondestructive and accurate. It provides a new method for the determination of soil water content.