应用近红外光谱分析技术对比研究基于土壤风干样本和鲜样来预测全氮含量的可行性。选取水稻土为研究对象，首先分析了不同水分土壤的光谱特征，显示随水分含量增加，吸光度升高，且鲜样的吸光度高于干样。通过比较不同预处理方法，对土壤干鲜样分别采用逐步多元回归(SMLR)和偏最小二乘法(PLSR)建立了相应的近红外模型。结果表明，利用近红外光谱均可预测干鲜土壤样本的全氮含量，特别是利用偏最小二乘法建立的标定模型，预测精度高，反演性较好，鲜样和干样外部验证决定系数分别达到0.89和0.91，相对误差仅为6.92% 和5.92%，研究结果可以为田间土壤全氮含量的估测提供技术依据和参考。

This paper was focused on analyzing the feasibility of predicting nitrogen contents in humid and dry soils with Near Infrared Spectroscopy (NIRS). The spectral characteristics of paddy soils in southern China were studied and the effects of different soil moisture contents on soil spectrum were analyzed. With moisture increasing, spectral absorbance hoisted and humid soil showed higher absorbance than dry one by adopting the pretreatment methods of spectrum, the calibration models were established with PLSR and SMLR. The result showed that total nitrogen in humid and dry soil samples both could be predicted by using near infrared spectroscopy, particularly by using the model established by PLSR. From external validation, Rv2 and RMSEP of dry soil and humid soil were 0.89 and 0.91, 6.92% and 5.92%, respectively. It may provide technical support for measuring soil total nitrogen content in the field.

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河南科技攻关项目(112102110030)、河南省教育厅项目(14A210002)、国家十二五科技支撑计划项目(2014BAD10B06)和河南农业大学科技创新基金项目(KJCX2015A12)资助