土壤可溶性有机氮测定方法研究进展

可溶性有机氮(DON)是土壤中生物可利用有机氮库的主要成分,是最为活跃的有机氮形态之一。DON在土壤中的迁移和转化是土壤氮素地球生物化学循环的重要一环,与氮素养分供应、损失等过程密切相关。然而缺失准确、可靠的土壤DON分析方法严重限制了DON的相关研究进程。本文综述了近年来国内外土壤浸提液和水体中DON测定方法,重点比较了不同可溶性总氮(DTN)测定方法以及不同前处理方法对提高DON测定结果准确性的影响。

Advances in Determination of Soil Dissolved Organic Nitrogen

Dissolved organic nitrogen (DON), as the main component of the bioavailable organic nitrogen pool in the soil, is one of the most active forms of organic nitrogen. As an important part of the soil nitrogen biochemical cycle, the migration and transformation of DON in the soil is closely related to the processes of nitrogen supply and loss. However, researches on soil DON were strongly limited by the lack of accurate and reliable analysis methods. Due to the presence of dissolved inorganic nitrogen (DIN) in the soil extract, it was currently difficult to directly determine the soil DON concentration. A subtraction method was required to subtract the DIN content from the total soluble nitrogen (DTN) content to calculate the DON content, and the subtraction method has been proved to accumulate multiple determination errors and affect the accuracy of the results. Previous studies have indicated that improvements can be made to improve the accuracy of DON analysis in two ways: one way was to improve the accuracy of DTN measurement, and the other was to reduce the proportion of DIN by pretreatment methods. This article summarized the DON determination methods in soil extracts and waters in recent years, and focused on comparing the effects of different DTN measurement methods and different pretreatment methods on improving the accuracy of DON analysis. Our results could provide reference and basis for establishing an accurate and reliable soil DON determination method.