subsoils

Below the topsoil

Subsoils is the plural of subsoil, the layer of earth lying immediately beneath the topsoil.

Unlike the dark, nutrient-rich surface layer, subsoil typically contains less organic matter and more clay or rock fragments.

Farmers and gardeners worry about compacted subsoils that prevent drainage: The subsoils here are mostly clay, so water pools after heavy rain.

layers

horizon

Apparent earth-sky meeting

claypanDense impermeable soil layer
hardpanImpenetrable subsurface stratum
calcicContaining calcium compounds

B horizon · profile · stratification · mottling

agriculture

drainage

Liquid removal system

percolationLiquid passing through pores
root zoneSoil surrounding active roots
fertilityCapacity for reproduction

nutrients · irrigation · tillage · compaction · aeration · waterlogging · leaching · pH balance · microorganisms · crop rotation

composition

clay

Moldable earth for ceramics

siltWaterborne earth particles
loamFertile soil mixture
sandFine rock particles

gravel · humus · organic matter · minerals · sediment · phosphates · chalk · sandstone · regolith · siliceous

geology

bedrock

Solid stone underground

permafrostPerpetually frozen earth layer
pedologyStudy of soils
weatheringAtmospheric breakdown of materials

sedimentation · laterite · calcification · salinization · loess · groundwater · water table

texture

porous

Allowing passage of fluids

permeableAllowing substances through
compactTightly packed together
denseClosely packed together

friable · crumbly · granular · coarse · fine · gritty · powdery · chalky · pebbly · impermeable

Opposites

soil depth/stratification

subsoilstopsoil

Nutrient-rich surface earth

topsoils · A horizon · tilled soil · bedrock · overburden

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