Based on the object-oriented concept,the hyperspectral intelligent monitoring system of major soil nutrients was designed and developed by using C# and ArcGIS Engine in combination with Microsoft SQL Server.The system mainly includes the following functions：file operation,basic map operation,spectral preprocessing,model management,nutrient content quick calculation,spatial distribution analysis,user management and so on.This system can accomplish the input and preprocessing of soil hyperspectra,and calculate the content of major nutrients,such as soil organic matter,nitrogen,phosphorus as well as potassium quickly and intelligently based on hyperspectral data.Thereby,the soil nutrients regional distribution in the research area can be analyzed by using the principle of geostatistics.This study can not only promote the practicability of soil quantitative remote sensing,but also provide references for the decision-making of agricultural fertilizing.
土壤水分的影响是当前采用光谱分析法预测土壤养分含量的关键问题，该文旨在探索去除土壤水分影响、提高有机质高光谱定量估测精度的方法。首先采用地物光谱仪进行湿土和过筛干土的高光谱测试，并进行一阶导数变换；然后，采用奇异值分解（singular value decomposition，SVD）结合相关分析筛选土壤水分特征光谱，构建去除水分因素的修正系数，形成湿土光谱的校正光谱；最后基于校正前后湿土光谱，应用偏最小二乘（partial least squares，PLS）回归构建土壤有机质含量的估测模型，并对模型进行验证和比较，分析评价校正前后光谱的预测精度。结果显示：按土壤水分含量梯度划分的2组和全部棕壤及褐土土样共4组样本校正后建模决定系数和均方根误差分别为0.85、0.82、0.74、0.76和0.19%、0.20%、0.23%、0.19%，决定系数提高了0.02～0.09，均方根误差降低了0.01～0.03百分点，验证决定系数、均方根误差和相对分析误差分别为0.78、0.77、0.72、0.76，0.21%、0.15%、0.21%、0.15%和2.03、2.02、1.86、1.98，决定系数提高了0.06～0.15，均方根误差除褐土土样提高0.02百分点外，其他样本组降低了0.01～0.08百分点，相对分析误差提高了0.17～0.43，模型决定系数和相对分析误差得到显著提升；尤其对于土壤水分含量变异系数较小的3组土样，模型从待改进级别提高到性能良好级别，对土壤有机质含量具有较好的预测准确性。说明该方法用于去除土壤水分因素影响和提高有机质含量高光谱估测精度的有效性。
