Iron-coated indicatorof reduction in soils (IRIS) devices have been used for nearly two decades to help assess and document reducing conditions in soils, and official guidance has been approved for interpreting these data. Interest in manganese (Mn)-coated IRIS devices has increased because Mn oxides are reduced under more moderately reducing conditions than iron (Fe) oxides (which require strongly reducing conditions), such that they are expected to be better proxies for some important ecosystem services like denitrification. However, only recently has the necessary technology become available to produce Mn-coated IRIS, and the need is now emerging for guidance in interpreting data derived from Mn IRIS. Ninety-six data sets collected over a 2-yr period from 40 plots at 18 study sites among eight states were used to compare the performance of Mn-coated IRIS with Fe-coated IRIS and to assess the effect of duration of saturation and soil temperature as environmental drivers on the reduction and removal of the oxide coating. It appears that the current threshold prescribed by the National Technical Committee for Hydric Soils for Fe-coated IRIS is appropriate for periods when soil temperatures are warmer (>11 °C), but is unnecessarily conservative when soil temperatures are cooler (5–11 °C). In contrast, Mn-coated devices are particularly useful early in the growing season when soil temperatures are cool. Our data show that when using a threshold of 30% removal of Mn oxide coatings there is essentially 100% confidence of the presence of reducing soil conditions under cool (<11 °C) conditions.

中文翻译：

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锰涂层 IRIS 可记录土壤条件的减少

土壤中的铁涂层还原指示剂 (IRIS) 设备已被用于帮助评估和记录土壤中的还原条件近二十年来，官方指南已被批准用于解释这些数据。由于锰氧化物在比铁 (Fe) 氧化物（需要强还原条件）更温和的还原条件下被还原，因此对锰 (Mn) 涂层 IRIS 设备的兴趣有所增加，因此它们有望成为某些重要生态系统服务的更好代表比如反硝化。然而，直到最近才有必要的技术可用于生产锰涂层 IRIS，现在需要指导解释从 Mn IRIS 获得的数据。在 2 年内从 8 个州的 18 个研究地点的 40 个地块收集的 96 个数据集用于比较 Mn 涂层 IRIS 与 Fe 涂层 IRIS 的性能，并评估饱和持续时间和土壤温度的影响作为减少和去除氧化物涂层的环境驱动因素。看来，目前由全国铁包覆 IRIS 水化土壤技术委员会规定的阈值适用于土壤温度较高 (>11 °C) 的时期，但当土壤温度较低 (5-11 °C) 时就显得过于保守了。 C）。相比之下，Mn 涂层装置在土壤温度较低的生长季节早期特别有用。