What does humus contain?

Answer 1

Based on the spelling, I'm guessing you'd like to know about the humus that's present in soil. If not, typing in "What is hummus?" in the white bar at the top of the webpage will give you the answer you're looking for!

Humus can be defined as the organic layers that are above the mineral soil horizons. The layers are split into three developmental layers (LFH): Litter, Fermentation and Humus.

Litter: (upper layer) contains fallen material like leaves, twigs and needles. There is no decomposition at this level, and it is very easy to recognize individual pieces of material.

Fermentation: (middle layer) Partially decomposed material resides here, although you may be able to make out parts of a twig or a leaf on occasion. Often, you can see threads of fungal hyphae from decomposing fungi or small microorganisms like insects.

Humus: (bottom layer) You cannot identify plant material as it is too decomposed here. The layer instead is black and greasy with organic matter.

There are 3 broad categories of Humus:

Mor:

Found: higher elevations, usually coniferous forests

Climate: moist and cool

Litter (L): thick, little breakdown of organic material

Fermentation (F): fungal mycelia is matted

Humus (H): Yes

(abrupt transitions between LFH layers)

Moder:

Found: mid-elevations, deciduous and coniferous forests

Climate: moderate

L: moderate to thick

F: fungal mycelium loose

H: Yes

(gradual transition between LFH layers)

Mull:

Found: low elevations, grasslands and/or very dry forests

Climate: warm, dry

L: thin

F: Thin to none

H: often not present

Answer 2

Humus helps the soil to hold water.