黑土腐殖酸的近红外光谱测定

研究了我国黑土腐殖酸碳含量及其光化学性质，并探索了利用近红外光谱分析法(near infrared spectroscopy, NIRS)对其进行预测的潜力。针对东北典型黑土带土壤样品，利用偏最小二乘法(PLSr)建立定量模型，并用独立样本对模型进行检验。结果表明，模型对腐殖酸碳、胡敏酸碳和富里酸碳含量的预测效果很好，NIRS对富里酸碳和胡敏酸碳的465 nm(E₄)和预测结果也较好，665 nm光密度(E₆)的预测达到可接受水平。胡敏酸碳和富里酸碳含量与SOC的相关性，高于其与NIRS模型预测值的相关性，二者光化学性质与SOC的相关性则低于其与模型预测值的相关性。NIRS在简化黑土腐殖酸碳、胡敏酸碳和富里酸碳含量和光密度测定领域具有很好的应用前景，且能够反映SOC性质方面的信息。

Assessment of Humic and Fulvic Acids in Black Soils Using Near-Infrared Reflectance Spectroscopy

The organic carbon content and optical densities of humic acids in black soils of China were predicted and assessed using near infrared spectroscopy technique. The contents of humic acid (HA) and fulvic acid (FA) in 136 black soil samples in China were analyzed and the NIR spectra were collected using a VECTOR/22 (Fourier transform infrared spectroscopy). Partial least squares (PLS) regression with cross validation was used to develop prediction models with reference data and soil NIRS spectra, and the model was validated using an independent set of samples. NIRS well predicted (HAC+FAC), HAC and FAC contents, with R2 = 0.92, 0.92 and 0.86, RPD=3.66, 3.82 and 2.69, and high correlation coefficients between predicted and measured values (r=0.90, 0.85 and 0.82). Predictions for the E4 values of HA and FA were also good (R2=0.85, 0.85; RPD=2.88, 2.65; r=0.92, 0.80). Predictions for optical densities of HA and FA at 665 nm (E₆) was acceptable. Generally, NIRS showed a good potential to predict C content and optical densities of humic acid and fulvic acid in blacks soils and may reveal information on SOC quality.