Camera illustration of Indicator of Reduction in Soils (IRIS) reduction dynamics

Abstract

Indicator of Reduction in Soils (IRIS) tubes or films are used with coatings of iron or manganese oxide to observe depth or occurrence of reducing conditions, with coating removal often assessed weekly. We evaluated the use of a rhizosphere camera to capture iron and manganese reduction (coating removal) at high temporal resolution. A rhizosphere tube was coated with iron and manganese oxide (two sections of each oxide) and inserted into a saturated column filled with a surface horizon from a wet soil (Fluvaquent). Images were taken hourly over 28 d and compared with Eh and pH data. Reducing conditions were observed for manganese and iron after 1 and 4 d, respectively. This technology builds upon an existing approach and could be used to evaluate real-time reducing soil conditions with IRIS as well as to improve oxide coating composition and tube/film development (e.g., coating thickness).