Gleyre refers to a pigmented soil horizon that is characterized by its blue-gray or greenish gray color, resulting from the accumulation of iron and manganese compounds. It typically occurs in poorly drained, waterlogged areas such as wetlands, floodplains, and swampy regions. Gleyre soils develop under reducing conditions in saturated environments, where oxygen is scarce or limited. The lack of oxygen creates an environment conducive to the reduction of iron and manganese minerals, leading to their precipitation and subsequent coloration of the soil.
The gleyre horizon is typically found below the surface, often beneath an oxidized horizon called the "ochric" or "rust" horizon. It exhibits a mottled appearance, with shades of blue, gray, green, or yellow dispersed throughout. The presence of gleyre often indicates waterlogging or poor drainage in the soil profile. As water accumulates in the soil, it restricts the amount of oxygen available to plant roots, affecting their growth and nutrient uptake.
The gleyre horizon has important implications for soil fertility and agricultural productivity. It hampers water infiltration and drainage, leading to waterlogged conditions that can hinder plant growth. Additionally, the reduced availability of oxygen in gleyre soils can affect microbial activity and nutrient cycling, potentially influencing nutrient availability and plant nutrient uptake.
In summary, gleyre refers to a pigmented soil horizon characterized by its blue-gray or greenish gray color, resulting from the reduction and accumulation of iron and manganese minerals in poorly drained, waterlogged environments.
