measurable soil properties

black soil

humus

when eluviated/leached, layer may appear bleached/whitish

Ar horizon lacks humus

white pale

Ae horizon: leached, eluviated

clay, organic matter washed out

exposes bar mineral grains

common in rainy temperate climates, forest soils

red

oxidation states of iron

blue/green/gray

presence of seasonally high water table

iron reduced, deprived of oxygen

structure

arrangement of sand, silt, clay, organic particles

tendency for particles to clump, form distinct structural units called peds/aggregates

soil structure in A/B horizon

crumb and granular: A horizon

platy, blocky prismatic/columnar: B horizon

soil pH

controls nutrient availability to plants, microbial decomposition rates…

soil ph in wet/dry regions

humid: slightly acidic

dryer: slightly basic

problem w low pH

nutrients less available

bacteria decrease

highly acidic, Fe n Al at toxic lvls