Soils with iron-cemented layers on golf courses in the USA

Layers cemented by iron and manganese have been observed in soils of putting greens at golf courses throughout the USA. They result in reduced water infiltration, saturated conditions in the root zone, and a decline in turfgrass density and quality. The physical and chemical properties of these layers have not been investigated nor described in detail. Here we present a detailed analysis of the physicochemical properties and a conceptual pedogenetic model for the formation of Fe-cemented layers in soils of golf putting greens across the USA. These man-made soils have an A horizon of about 5 to 10 cm over 20 to 30 cm sand (C horizon) over gravel. The Fe-cemented layer is commonly found at the interface of the A and C horizons, or the C horizon and the gravel layer. Levels of total Fe in the cemented layers range from 0.41 to 16.21 g kg− 1 and these are accompanied by accumulations of SOC and sometimes high levels of Mn and Al. The downward movement of water (irrigation), high levels of Fe (fertilization), and a textural discontinuity are key factors in the formation of the Fe-cemented layer. The layers may form at rates as high as 1.5 mm per year depending on Fe content and redox conditions in the root zone, and may become cemented in 10 years. These cemented layers meet the criteria of the placic horizon in Soil Taxonomy.