1. in the Tongariro Volcanic Centre
Soil
The spatial variation of
in the Tongariro Volcanic Centre

2. Spatial Pattern of Soils in the Tongariro Volcanic Centre
SOILS KEY:
Azonal soils
Soils that Lack nutrients
Pumice soils and Rich red Ohakune soils
Tongariro Ash soils and fine textured loam
No soil

3. What are soils?
Soils are the natural materials on the land's surface that directly support plants and bacteria, and indirectly support all animal and human life.

4. Soils are made up of:
topsoil (the dark layer that you can see), which has a lot of microbes and organic matter from previous plant growth
subsoil, which has a variety of colours and textures depending on drainage and past weathering
underlying rocks.

5. How they form
Soil builds up over time. Through gradual wearing and chemical decay, rock breaks down into smaller particles – gravels, sands, silts and clays. During this process nutrients are released, and become part of the soil.
Many New Zealand soils are made from a build-up of fine, wind-blown sediments (loess), volcanic ash or pumice.

6. Layers of Soil

7. Each soil horizon has specific physical and chemical properties.
O horizon (surface litter): Fresh or decaying organic material (e.g., leaves, twigs, moss) accumulated on the ground.
A horizon (topsoil): Top layer of soil, which holds most of the organic matter and most of the water and nutrients needed for life. Infiltration: Seeping of water down through soil.
E horizon: Zone through which leaching occurs. Leaching: Process by which infiltrated water picks up nutrients and carries them down to deeper soil.
B horizon (subsoil): Zone that often contains an accumulation of minerals as well as some organic materials.
C horizon: Zone composed of broken-down parent material, the basic type of rock from which the rest of the soil is derived.
Bedrock: Parent material below the C horizon.
Erosion occurs when wind, water, or other erosive agents dislodge and move soil from one location to another.
After topsoil is eroded from an area, the area is generally infertile and inhospitable to life, for topsoil contains most of the nutrients and the water-holding capacity of soil.
If fertile soils are allowed to erode for a long period of time, the land will eventually convert to desert, a process known as desertification.
Although soil can regenerate slowly, the rate of erosion in many places vastly exceeds the rate of potential regeneration.

8. Soil types in New Zealand Can you identify any patterns?
Very technical map, but can generalise about the types found in eg auckland area, west coast SI. Note the pumice!write a statement about the location of pumice soil and the prevailing wind direction

9. Recent Soils
Recent soils cover 6% of New Zealand. They occur where erosion and sediment build-up are low enough to allow well-developed topsoils to form. However, subsoils usually show very little development. Many of New Zealand’s most versatile soils are Recent soils. They are usually fertile and allow plant roots to penetrate deeply, unless rock or dense clay is present.
The highest recorded carrot production in the world, was from a Recent Soil on the Taieri Plain. Recent Soils are weakly developed, showing limited signs of soil-forming processes. A distinct topsoil is present but a B horizon is either absent or only weakly expressed. OCCURENCE: Recent soils occur throughout New Zealand on young land surfaces, including alluvial floodplains, unstable steep slopes, and slopes mantled by young volcanic ash. Their age varies depending on the environment and soil materials, but most are less than 1000 to 2000 years old. They cover 6% of New Zealand. ...(click for map of Recent)
PHYSICAL PROPERTIES: The soils have variable soil texture, with common stratification of contrasting materials, and spatial variability is high. They are generally deep rooting and have high plant-available water capacity.
CHEMICAL PROPERTIES: Natural fertility is usually high with high base saturation. The clay mineralogy is usually dominated by iIlite.
BIOLOGICAL PROPERTIES: A continuous cover of vascular plants is normally well establish
This soil has been undisturbed long enough to develop a clear topsoil horizon, but not long enough for any differentiation of the subsoil to occur. However, narrow bands of alluvium left by flooding at different times can be seen, especially in the lower depths. Recent soils are usually very fertile and can be used for a wide range of purposes, especially if they are deep and free-draining.
ed.

10. Raw Soils
Infant soils that may never grow older because of active erosion or sedimentation. Raw Soils are very young soils. They lack distinct topsoil development or are fluid at a shallow depth. They occur in environments where the development of top soils is prevented by rockiness, by active erosion, or deposition
Infant soils that may never grow older because of active erosion or sedimentation. Raw Soils are very young soils. They lack distinct topsoil development or are fluid at a shallow depth. They occur in environments where the development of topsoils is prevented by rockiness, by active erosion, or deposition. OCCURENCE: Raw Soils are scattered throughout New Zealand, particularly in association with high mountains (alpine rock areas and active screes), braided rivers, beaches and tidal estuaries. They cover 3% of New Zealand. ...(click for map of Raw)
PHYSICAL PROPERTIES: Raw Soils have no B horizon, and a topsoil is either absent or less than 5 cm thick. Most occur in environments with active erosion or deposition. Fluid soils have a continuously high water-table.
CHEMICAL PROPERTIES: Fertility is limited by lack of organic matter and nitrogen deficiency.
BIOLOGICAL PROPERTIES: Vegetation cover is sparse and often consists of ephemeral herbaceous plants, mosses, or lichens.

11. Pumice Soils
Mostly derived from one of the greatest volcanic eruptions ever known from the crater now occupied by Lake Taupo. Pumice Soils are sandy or gravelly soils dominated by pumice, or pumice sand with a high content of natural glass. Drainage of excess water is rapid but the soils are capable of storing large amounts of water for plants. They occur in tephras ranging from 700 to 3500 years old.
Mostly derived from one of the greatest volcanic eruptions ever known from the crater now occupied by Lake Taupo. Pumice Soils are sandy or gravelly soils dominated by pumice, or pumice sand with a high content of natural glass. Drainage of excess water is rapid but the soils are capable of storing large amounts of water for plants. They occur in tephras ranging from 700 to 3500 years old. OCCURENCE: Pumice Soils occur predominantly in the central North Island, particularly in the Volcanic Plateau. They cover 7% of New Zealand. ...(click for map of Pumice)
PHYSICAL PROPERTIES: Clay contents are low, generally less than 10%. They have low soil strengths, high macroporosity, and deep rooting depth. Soils have low strength when disturbed, but are generally resistant to livestock treading damage.
CHEMICAL PROPERTIES: The pumice is fresh or only moderately weathered with low reserves of major nutrient elements. Trace elements are likely to be deficient. Clay minerals are dominated by allophane.
BIOLOGICAL PROPERTIES: Soil animal populations are low with most species concentrated in the topsoil. Earthworm populations are limited by droughtiness and coarse texture.

12. Podzols Soils
Podzolised soils cover 13% of New Zealand. The name podzol comes from a Russian word for wood ash, describing the white subsoil – digging through the thin black topsoil exposes an almost white horizon (layer). Digging deeper reveals a bright ginger brown. These colours have been caused by strong acid leaching from native trees (especially conifers, beech and kauri) and high rainfall (more than 1,300 millimetres per year).
The impressive contrast in horizons displays the potent effect that particular tree species, for example Kauri, can have on soil formation. Podzol soils are strongly acid soils that usually have a bleached horizon immediately beneath the topsoil. This horizon is the source of aluminium and iron oxides that have accumulated, in association with organic matter, in an underlying dark or reddish coloured horizon. The rain water carries acids from the trees, stripping aluminium and iron from the upper part of the soil and leaving it bleached white. It deposits the elements along with coloured organic matter, creating the ginger-brown layer
OCCURENCE: Podzol Soils occur in areas of high rainfall and are usually associated with forest trees with an acid litter. The soils occur mainly in materials from silica-rich rocks. They cover 13% of New Zealand.
PHYSICAL PROPERTIES: Cemented or compacted B horizons are common, with associated slow permeability and limited root depth. E and B horizons are weakly pedal or lack pedality.
CHEMICAL PROPERTIES: Podzol soils have low natural fertility, low base saturation, and are strongly acid. Secondary oxides and other clay minerals are strongly differentiated with depth.
BIOLOGICAL PROPERTIES: Podzols have low biological activity. The vegetation comprises plants that deposit a mor-forming acid litter.
CLIMATE: The soils are moist throughout the year with annual rainfall more than about 1500mm.

13. Zonal Soils
The zonal soils clearly the impress of climate and vegetation. It consists of the brown-grey earths of the semi-arid areas where the rainfall is less than about 20 inches a year; the yellow-grey earths of sub-humid areas where the rainfall is approximately 20–40 in. a year; the high country, central and southern, and northern yellow-brown earths of the humid regions where the rainfall is well distributed and is greater than approximately 40 in. a year; and the corresponding podzolised yellow-brown earths and podzols resulting from excessive leaching beneath an acid litter of decomposing vegetation.

14. Azonal Soils
azonal soils, are zonal soils that have been changed as a result of variations in topography, such as erosion, moisture status, and depth to bedrock
Azonal soils are youthful
Azonal soils include some mountain, alluvial, marine, glacial, windblown, andvolcanic soils

15. Variation of Soils in the TVC
Southern foothills: Tongariro ash soils and fine textured loam
Eastern: Azonal soils. Ash covering up to 2 metres of Taupo pumice
Western foothills have Yellow-brown pumice soils and rich red Ohakune zonal soils
Western slopes (I couldn’t find a name for these) soils thin and lack basic nutrients

16. There are 5 categories – with 4 actual soils to map.
No soils
Tongariro Ash soils and fine textured loam
Yellow-brown pumice soils and rich red Ohakune zonal soils
Thin soils that lack nutrients
Azonal soils. Ash covering up to 2 metres of Taupo pumice
In this map, all areas of the map will be covered as all the soils are a natural feature.
Locating the soils:
No soils: are located around the mountain peaks in the same location as the bolder fields on your vegetation map – except they only are located on the peaks – do not come down the eastern side of the mountain.
Tongariro Ash soils and fine textured loam: are located in two areas. The first in the NE quadrant where the kanuka and manuka are growing. The second is around the southern slopes of Ruapehu – where the exotic forest is located and all the beech and podocarp forest are located.
Azonal soils: are located on the Rangipo desert between the two Tongario ash soils.
The last two are located on what is left of the Northern and western slopes. Visually divide this area in half vertically. The most western side is the Yellow-brown pumice soils and rich red Ohakune soils. The inner western slopes are the thin soils that lack nutrients.

17. Variation of Soils in the TVC
Southern foothills: Tongariro ash soils and fine textured loam
Eastern: Azonal soils. Ash covering up to 2 metres of Taupo pumice
Western foothills have Yellow-brown pumice soils and rich red Ohakune zonal soils
Western slopes (I couldn’t find a name for these) soils thin and lack basic nutrients

18. Variation of Soils in the TVC
Southern foothills: Tongariro ash soils and fine textured loam
Eastern: Azonal soils. Ash covering up to 2 metres of Taupo pumice
Western foothills have Yellow-brown pumice soils and rich red Ohakune zonal soils
Western slopes (I couldn’t find a name for these) soils thin and lack basic nutrients

19. How does each factor affect the soil fertility / location CARVES
C = Climate
A = Altitude (height)
R = Relief (steep or flat?)
V = Vegetation
E = Eruptions
S = Stage of development
(this is the heading – you don’t have to write anything except the stage number)

20. Variation of Soils in the TVC
Southern foothills: Tongariro ash soils and fine textured loam
Eastern: Azonal soils. Ash covering up to 2 metres of Taupo pumice
Western foothills have Yellow-brown pumice soils and rich red Ohakune zonal soils
Western slopes (I couldn’t find a name for these) soils thin and lack basic nutrients

21. Tongariro Ash Soils & Fine Textured Loam
Climate: Eastern side: Not that much rainfall – 1048mm per year due to rainshadow effect of Mt T and Mt N. This means there is very little leaching of the nutrients from the soil.
South Western & Southern sides: While there are high levels of rainfall due the orographic rainfall caused by Mt R; over a long period of time this has caused the area to have a very lush vegetation which then significantly contributes to the nutrient cycle keeping the soils fertile. Here the vegetation keeps the soils from being leached.
This soil is important and is widespread in TVC

22. Tongariro Ash Soils & Fine Textured Loam
Altitude:
m high.

23. Tongariro Ash Soils & Fine Textured Loam
Relief:
Rolling foothills – soils are able to remain on this type of terrain as it is not too steep.

24. Tongariro Ash Soils & Fine Textured Loam
Vegetation: Beech, Podocarp and Scrubland. Good vegetation helps add to the nutrient cycle. The more vegetation, the more decaying of leaves the more nutrients are then added back into the soil. Therefore these soils are very fertile.

25. Tongariro Ash Soils & Fine Textured Loam
Eruptions (in history):
Eastern side: Mt T & Mt N last erupted in 1974 which means that the soils have had to re-develop their fertility in the last 40 years.
South Western & Southern sides: Up until the 1990s, Mt R had been relatively dormant due to the hot spot being in the north. This meant that soils have had a long time to redevelop their fertility. Today, the prevailing Westerly winds help to maintain this fertility by blowing the ash to the East meaning that the soils are less affected.

26. Tongariro Ash Soils & Fine Textured Loam
Stage:
Later stage of development – nutrients are present
It takes approximately 50 years for soils to become fully fertile after eruptions.
These soils have not been greatly affected by eruptions for over 40 years.
Fine texture, dark brown, mixed with ash from the Tongariro eruption. Quite fertile.

27. Yellow-Brown Pumice & Rich Red Ohakune Zonal Soils
Climate:
2800mm of rainfall due to orographic rainfall which has leached the soils in the past due to the slow vegetation succession

28. Yellow-Brown Pumice & Rich Red Ohakune Zonal Soils
Altitude: Low

29. Yellow-Brown Pumice & Rich Red Ohakune Zonal Soils
Relief: Rolling relief is not steep and so does not inhibit the soil (and vegetation) to develop

30. Yellow-Brown Pumice & Rich Red Ohakune Zonal Soils
Vegetation:
Mainly tussock and scrubland. On these lower foothills there is more scrubland than tussock leading to more soil development as the vegetation adds to the nutrient cycle and is helping to reduce the leaching of the soils.

31. Yellow-Brown Pumice & Rich Red Ohakune Zonal Soils
Eruptions:

32. Yellow-Brown Pumice & Rich Red Ohakune Zonal Soils
Stage of Development:

33. Thin soils that lack nutrients Sheenal
C = high amounts of leeching due to high levels of rainfall from the orographic effect. This removes nutrients from the soil A = m R = Steep slopes of the mountain make it harder for the soil development process to occur V = Small amounts of vegetation, not enough soil to grow all types of vegetation E = Relatively close proximity to vents means that the soil is vulnerable to damage from eruptions S = Middle stage of development with some nutrients

34. Azonal Soils Monleigh
C = Rain shadow effect occurs as a result of prevailing SW wind, strong winds. SW wind carries ash over this area
A = m
R = Relief is relatively flat; on the ring plain of Ruapehu
V = Vegetation is mainly tussock and scrub
E = Eruptions have prevented the regrowth of forest on the slopes due to SW winds
S = Early stage of development because of Aeolian erosion and sedimentation

35. Soil Categories
Zonal Soils: Determined by the climate and vegetation. These are older soils.
Azonal Soils: Determined by other factors like alluvial (to do with rivers), moraine (to do with glaciers), aeolian (to do with wind) and tephra (to do with volcanoes). These are young soils.

36. Yellow-brown pumice soils and rich red Ohakune zonal soils
YB – silt to coarse gravel , good drainage because the pumice is porous, a bit of clay.
RO zonal soils – older soils created from different tephra from Mt T and N’s eruptions.
Southern foothills: Tongariro ash soils and fine textured loam
Eastern: Azonal soils. Ash covering up to 2 metres of Taupo pumice
Western foothills have Yellow-brown pumice soils and rich red Ohakune zonal soils
Western slopes (I couldn’t find a name for these) soils thin and lack basic nutrients

37. Azonal soils
Young soils created from the deposition (the depositing) of tephra from Mt Ruapehu ash covering 2m of Taupo Pumice soils.
Southern foothills: Tongariro ash soils and fine textured loam
Eastern: Azonal soils. Ash covering up to 2 metres of Taupo pumice
Western foothills have Yellow-brown pumice soils and rich red Ohakune zonal soils
Western slopes (I couldn’t find a name for these) soils thin and lack basic nutrients

38. Tongariro Ash Soils and Fine Textured Loam
Fine texture, dark brown, mixed with ash from the Tongariro eruption. Quite fertile.
Southern foothills: Tongariro ash soils and fine textured loam
Eastern: Azonal soils. Ash covering up to 2 metres of Taupo pumice
Western foothills have Yellow-brown pumice soils and rich red Ohakune zonal soils
Western slopes (I couldn’t find a name for these) soils thin and lack basic nutrients

39. Thin soils, lack nutrients
Very coarse gravels, low levels of actual soil. Leaching occurs very easily here.

40. The final product: A Study Summary of Soil in the TVC
Use the colour print out(the soil map I gave you last Thusday) and the notes from this PowerPoint to make a layout that looks like the following slide…
(either hand write it- or type and print it)
NOTE: your layout will have more information than this one example box so don’t simply copy it out!

41. Spatial Pattern of Soils in the Tongariro Volcanic Centre
Soils that lack nutrients
Stage of soil devt: Middle stage as there are only some nutrients
Climate: 2838mm rainfall means lots of leaching
Altitude:__________
Eruptions: The Taupo Caldera erupted approximately 2000yrs ago wiping out the podocarp forest that existed here. Subsequent eruptions from Tongario and Ngauruhoe have continued to slow soil devt by depositing ash and making the soil acid. Until 2012, the last eruption was over 50yrs ago, allowing acidity to reduce and fertility to increase.
Vegetation: Tussock and scubland like flax is growing slowly beginning to hold the soil together and adding nutrients to the soil through decomposition processes.
Relief: Relatively flat with a few small rolling valleys which means that soil is generally able to stay in one location, as long as it is protected by vegetation.
Spatial Pattern of Soils in the Tongariro Volcanic Centre
Northern Tongariro Ash Soils and Fine Textured Loam
Climate
Altitude
Relief
Vegetation
Eruptions
Stage of soil Development.
Azonal SoilsClimate
Altitude
Relief
Vegetation
Eruptions
Stage of soil Development.
Pumice Soils & Rich Red Ohakune Soils
Climate
Altitude
Relief
Vegetation
Eruptions
Stage of soil Development.
SOILS KEY:
Azonal soils
Soils that Lack nutrients
Pumice soils and Rich red Ohakune soils
Tongariro Ash soils and fine textured loam
No soil
Southern Tongariro Ash Soils and Fine Textured Loam
Climate
Altitude
Relief
Vegetation
Eruptions
Stage of soil Development.

42. It’s not just the soil that ash lands on!