Nitrate Nitrogen Quantification via Ultraviolet Absorbance: A Case Study in Agricultural and Horticultural Regions in Central China

作者：Yiheng Zang, Jing Chen, Muhammad Awais, Mukhtar Iderawumi Abdulraheem, Abiodun Yusuff Moshood, Kuan Geng, Yongqi Chen, Yani Xiong, Linze Li, Yanyan Zhang, Vijaya Raghavan, Jiandong Hu, Junfeng Wu, Guoqing Zhao · 发表于：Agriculture · 年份：2025 · DOI：10.3390/agriculture15111131 · 被引用次数：6 · 研究领域：Water Quality Monitoring and Analysis、Isotope Analysis in Ecology

Soil nitrate nitrogen (NO3−-N) is a key indicator of agricultural non-point source pollution. The ultraviolet (UV) dual-wavelength method is widely used for NO3−-N detection, but interference from complex soil organic matter affects its accuracy. This study investigated how organic matter influences NO3−-N detection by optimizing UV dual-wavelength combinations. Density functional theory (DFT) calculations showed slight spectral broadening of fulvic and humic acids in the presence of NO3−-N under UV spectrum. Standard solutions and soil samples were used to compare the detection performance of different wavelength pairs. The findings indicated that the dual-wavelength combination of 235 nm/275 nm is optimal rather than 220 nm/275 nm for measuring soil samples at NO3−-N concentrations exceeding 5 mg·L−1. The 235/275 nm method gave an average calibration coefficient of 1.57. Compared to the national standard and flow analysis methods, the average relative errors were 19.7% and 22.3% (p < 0.001), respectively, indicating its suitability for practical soil applications. These results demonstrate the method’s potential for rapid and accurate NO3−-N detection in real soil samples, supporting its application in environmental monitoring and agricultural management.