Litter Layers

Litter layers are very important to forest nutrition. Essential nutrients for plant growth such as nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), etc. are contained in all forms of plant detritus (leaves, needles, twigs, stems, woody roots and small, non-woody absorbing roots). As litter is deposited on the forest floor or directly in the mineral soil via root mortality, it begins to decompose. Decomposition of plant litter is an important source of essential nutrients. A portion of the fresh litter is transformed in the soil by the soil foodweb (bacteria, fungi, insects, and other soil animals), where it becomes relatively stable soil organic matter. In this picture you can see partially decomposed litter on the surface of the mineral soil ("O" soil horizons). Below the litter layers is a dark soil horizon that represents a zone where organic matter has been incorporated into the mineral soil ("A" soil horizon). Below this dark, blackish layer is a relatively thick layer of mineral soil that has been chemically leached of iron and aluminum oxides and organic matter ("E" soil horizon). Plant litter plays a key role in soil formation and is a dynamic soil property that is directly related to the type of dominant vegetation.

Return to Soils and Soil Water