biosphere Flashcards
what is leaching
where soluble material is washed down from one soil horizon to the one beneath with gravity. lots of leaching can lead to upper mineral horizons becoming less fertile
what is capillary action
where moisture moves upwards in a soil. where evaporation is faster than rainfall.
what is decomposition
the breakdown of plant derived material into its simpler organic parts. done by soil boots and enzymes
what is humification
the complete breakdown of plant remains leading to the formation of the different types of humus
what are the different types of humus
mull, moder and mor
when does mull humus form
develops under deciduous woodland where plant remains are actively broken down by a prolific soil biota (lots of soil biota)
what is moder humus
the intermediate between mor and mull
when is mor humus formed
usually develops beneath coniferous woodlands under a cool, wet climate condition. breakdown is slow due to lack of soil biota
what is weathering
weathering is the breakdown and decomposition of rocks and minerals by factors including air, water, sun and frost.
what is translocation
the movement of material in solution or suspension from one horizon to another
what is eluviation
downward movement of material where rainfall is more than evaporation (E= exit)
what us illuvistion
accumulation of material in one layer of soil which have been leached from a layer above (I- into)
what factors form soil
climate, time, living organisms, events
what part does climate have on soil
warm temps allow rapid decomposition of material into soil whereas cold temps limit the growth of plants and slow decomposition making soil less fertile
what effects do living organisms have on soil
worms and other creatures help to mix and improve the soil by encouraging air into the soil and encouraging breakdown of organic material. the more soul biota the richer the soil
what effect does time have in soil
it can take 200-400 years for 1cm of soil to form. therefore the older the soil the deeper it is
what effect do events have on soil
events like volcanic eruptions and floods can displace soil and limit what can grow on it
how is brown earth soil formed
the deciduous forest vegetation provides deep leaf litter which is broken down rapidly by the warm climate. the trees long roots go deep into the soil accessing nutrients from the lower layers. the soil boots ensures the mixing of the soil, aerating it and preventing the formation of distinct layers. the climate impacts the formation as precipitation exceeds evaporation meaning there is alot of leaching and the possibility of an iron pan forming. brown earth soil tends to be found in gentler leading to lower rates of erosion (so thicker soil)
how is podzol soil formed
the low temperatures of the climate lead to slow decomposition so the needles from the coniferous woodland produce acidic mor humus. the high rainfall leads to leaching and forms an iron pan between the A/B horizons. the iron pan may impede causing water logging. eluvation leaves an ash grey A horizon. and illuviation leads to a red/brown horizon. the lack of soil biota leads to well defined horizons and podzol soil is found on steep slopes.
how is gley soil formed
gley soil is found on gentler slopes, cool to cold climates which lead to a very slow rate of decomposition. the plant roots don’t go very deep so there is a limited recycling of minerals back to the vegetation. not much soil biota. the limited soil biota in the soil extract the oxygen they needs from the iron compounds meaning the soil has a blue colour due to anerobic condition. the impermeable clay texture impedes drainage and caused water logging. poor drainage is the key soil forming feature for this soil type
what is the hydrological cycle
the water cycle involved water that is being evaporated, moving around in clouds or in surface run off to other places. the water is never lost, only moved around. the water cycle shows the continuous movement of water within the earth and atmosphere
what are inputs to the hydrological cycle
an input is something that puts moisture/energy into the hydrological cycle system eg. solar energy
what is storage in the hydrological cycle
something that stores moisture within the hydrological cycle eg. lakes, glaciers, evaporation
what are transfers within the hydrological cycle
things that transfer moisture from one place to another eg. glaciers, evaporation, condensation
