The class Anmoor is characterised by an Aa horizon and has a content of organic carbon between 8 and 15% by mass, occurring mostly as fine humus. The Aa typically has a thickness of 20–40 cm. Varieties are differentiated according to the N content trophic grades). The pedogenesis of these Aa horizons with intermediate content of organic matter is not yet described, but deposition of mineral soil and temporary aerobic conditions affecting mineralisation of the organic matter are probably factors for the development of Aa horizons.

OA                  Type Anmoor

• Aa horizon (Go-Aa, Aa-Go, Sw-Aa) is present almost all year round and
• Aa horizon is topsoil under the long-term impact of stagnant water or groundwater

Humus form Anmoor, horizon sequence: Ol / (Of) / Go-Aa / decomposability of leaf material high to very high, © Gerhard Milbert