biosphere

Question 1

podzols characteristics

Answer 1

coniferous woodland/ heather moorland

layer of needles and cones

black humus (mor) produced from minimal leaf litter

some darker staining in upper A horizon

shallow spreading roots

ash grey lower A horizon with sandy texture

iron pan develops in lower A/ B horizon

impeding drainage

well defined horizons

few soil horizon

B horizons is reddish brown with denser texture

downward movement of water

C horizon is generally glacial or flurioglacial material

partially/ not well weathered parental material

Question 2

7 podzols conditions and processes

Answer 2

short rooted vegetation means for less mixing, therefore separated layers

leaching of aluminium oxide starts to create brown layer

next layer is grey due to continuation of leaching

organisms keep nutrients in soil and they don’t move very much among layers

low temperatures lead to slow decomposition

iron pan impede drainage causing water logging

limited soil biota leads to well defined horizons

Question 3

brown earth characteristics

Answer 3

abundant leaf litter from trees

thick (mull) humus, dark in colour with loamy texture, mildly acidic

darker brown layer

iron pan can develop occasionally

light brown layer

deep roots taking up minerals and mixing soil

weathered parent materials e.g. schist

Question 4

brown earth processes

Answer 4

natural vegetation- deciduous vegetation provides deep leaf litter, which is broken down rapidly in mild/ warm climate

trees have long roots penetrating deep into soil, accessing lower level nutrients which are recycled to leaves

soil organisms- ensure soil mixing, aerating it and preventing distinct soil layers

climate- precipitation slightly exceeds evaporation, giving downward leaching of most soluble minerals and possibility of an iron pan forming, impeding drainage

aspect- south facing slopes in northern hemispheres with greater amount of sun and higher temperatures increase the rate of decomposition, resulting in humus layer

rock type- determines rate of weathering, with hard rocks like schist taking longer to weather, producing thinner soils, and softer rocks such as shale weathering quicker

relief- often found on gentler slopes leading to lower rates of erosions, so thicker soils

Question 5

tundra gley characteristics

Answer 5

cold and wet climate

extremely cold most of year

limited leaf litter with partial decomposition

thin black humus (mor)- peaty

blue-grey clayey mud (waterlogged)

anaerobic reaction gleying

large angled fragments due to slow weathering

permafrost prevents drainage

bedrock

Question 6

tundra gley conditions and processes

Answer 6

limited vegetation produces thin acidic organic layer/ mor humus and low temps cause slow decomposition rate

heavy precipitation/ snow melt causes waterlogging and found on flat surfaces on relief can cause drainage problems- as can impermeable days

waterlogged soil creates anaerobic conditions, meaning iron compounds are changed from red brown to blue, due to oxygen extraction by microorganisms

cold temperatures/ waterlogged conditions mean few organisms can survive

limited biota reduces mixing causing clearly defined layers

burrowing animals/ soil drying out in summer leave oxygen pockets allowing for re-oxygenation for the iron in soil causing red mottling effect

shallow roots limit the recycling of materials/ minerals

freeze-thaw takes place causing vertical mixing, causing large angled rock chunks rising to A and B horizons