The concepts of soil security (especially relating to soil condition) provide a useful framework in building spectral libraries. Spectral libraries can be used with the purpose of assessing soil condition by measuring soil organic carbon (SOC) or increasing productivity through soil nutrient management. A spectral library was generated by measuring SOC and nutrients (nitrogen, phosphorous and potassium) and spectral reflectance data over the visible to near-infrared range (350–2,500 nm) in soil samples collected from four production systems in Papua New Guinea (PNG). The spectral library was analysed using SpecOptim, a software tool developed at the James Hutton Institute to explore spectral pre-processing and calibration options. From 192 model combinations of model, the best one was identified for each study area. Different combinations of data were also explored (e.g. by farm or all together). We believe that at the local-scale, soil carbon and nitrogen variability can be captured; however, the spectrally inactive properties such as phosphorous and potassium need to have a higher variability and therefore pooling is required in order to predict properties chemometrically. The SpecOptim software is a useful tool where analysis of spectral data can be difficult to determine. Specifically, it helped improve the accuracy of predictions by 2% for C and N (except for East New Britain site) compared with previously used pre-processing techniques and calibration models while automating identification of the optimal pre-processing approach. We believe that we have developed research-based evidence for using spectral libraries to fit with the soil priority areas of PNG.

中文翻译：

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小型农场土壤状况估计光谱预处理的优化

土壤安全的概念（尤其是与土壤条件相关的）为构建光谱库提供了一个有用的框架。光谱库可用于通过测量土壤有机碳 (SOC) 或通过土壤养分管理提高生产力来评估土壤状况。通过测量从巴布亚新几内亚 (PNG) 的四个生产系统收集的土壤样品中可见光至近红外范围 (350–2,500 nm) 的 SOC 和养分（氮、磷和钾）和光谱反射率数据，生成了一个光谱库. 光谱库使用 SpecOptim 进行分析，SpecOptim 是 James Hutton 研究所开发的一种软件工具，用于探索光谱预处理和校准选项。从模型的 192 个模型组合中，为每个研究区域确定了最佳组合。还探索了不同的数据组合（例如按农场或全部一起）。我们相信，在局部尺度上，可以捕捉到土壤碳和氮的变化；然而，光谱上不活跃的特性（如磷和钾）需要具有更高的可变性，因此需要合并以便从化学计量学上预测特性。SpecOptim 软件是一个有用的工具，用于分析难以确定的光谱数据。具体来说，与以前使用的预处理技术和校准模型相比，它有助于将 C 和 N（东新不列颠地区除外）的预测准确度提高 2%，同时自动识别最佳预处理方法。