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How our present day soils came to be:
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 The changes from parent material to the soils we have today, started
millions of years ago.
-Large
rocks have fragmented into smaller, then smaller, then yet smaller pieces, and again and again
and again.
-The climate:
The heat of the sun, the cold of a frost have accelerated the fragmentation of rocks.
Wind and rain also help. This process is called WEATHERING.
Photo: The Manawatu river
in a BIG FLOOD..
The mass of rain
causes slips... Trees get caught up in the swift flowing river.
The "dirtiness of the water" indicates an amount of soil is being swept
down the river..
Some of this soil spreads onto low lying areas near the river.. ON land
it is called silt.
Stones are moved about.. some fracturing weaker stones..
A valley floor receives particles washed down by rain, or dropped by
gravity. This explains why mountains slopes are rocky, and often
the valley floor has soil.
Over millions of years:
Our beaches, riverbeds, lakebeds, and our present day soils have all develped.
The speed of rock to soil transition varies with location.
Photo right: A volcanic
eruption in New Zealand:
Earthquakes, and volcanic eruptions over the years have rearranged the
landscape, and erupted material.. now as parent material have influenced
our today's soils.. Some areas being deficient in cobalt.
Often a volcanic eruption may provide even very far away locations
"free" sulphur.
Animals, bugs, worms, plant material, bacteria and man, have all contributed to our present day soils.
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The Roots of plants:
These help to build up the soil, by supply root exudates. Bacteria, are added especially by legumes. The roots push their way through the soil to find moisture and nutriments. A well anchored plant actually protects the soil from wind, and allows water from heavy rains to soak into the ground. Dead and composting roots contribute to soil health.
Soil Micro organisms (or microflora):
Fungi can break down large plant molecules in dead leaves or wood. Fungi are the "first in" to break down plant material.
Bacteria:
Some are responsible for oxidation. Some break down cellulose
Algae:
Soils have a great population of algae. They add a great amount of organic material to the soil because of their immense numbers.
Micro: means you need a microscope to see them.
Macro: visible without a microscope.
Spiders, insects, and larger soil animals are called soil macro organisms,
and collectively all are called "soil biota".
Earthworms:
The soil is the earthworms natural home.
 The soils structure, stability, and fertility (natural) are all helped by the earthworm.
A large earthworm population = a high micro, and macro organism population.
As worms burrow through the soil they mix the various layers.
Castings,(excreta) formed from the mix of layers is then deposited on the soil surface. So eventually the surface is a rich topsoil.
Earthworms burrowing also opens up channels for oxygen, roots, and for rainfall to enter.
The very top layer of the soil is called the "Litter Layer" because of the "litter", e.g. dead leaves, and the organic matter that collects there.
Rotting of this litter is started by bacterial action. The worms ingest this litter, and exrete worm castings.
Worm castings:
Act as a fertiliser. The earthworms simple digestive system conveys insoluble minerals and plant matter into a plant available soluble
form.
Nutrient Cycles:
Soil nutrients are lost through: leaching, erosion, animal feed, crops, hay or silage. During photosynthesis plants capture carbon from the atmosphere, and combine it with water, and mineral nutrients through the plant roots. When a plant dies, or becomes animal dung, after being eaten, the complex organic molecules are broken down in the soil. The releasing of mineral nutrients and carbon dioxide complete the cycle.
Macronutrients of the soil:
Nitrogen(N) Potassium(K) Phosphate(P) Sulphur(S)
These major nutrients are lost from the soil by: animal ingestion, crops, hay, dentrification, and leaching. The loss varies according to soil type, and land use. The macronutrients are replaced by applying fertilisers.
Soil Types:
Soil types vary from district to district.
To the naked eye all soils may appear identical, but soil types vary from
district to district. Different soil types may have a different fertiliser requirement from
other districts.
Hint: Ask about the fertiliser history prior to buying land.
There are district maps available with soil type information. (farm consultants, fertiliser consultants may have them)
Soil, and herbage tests will give you the information on the need of soil nutrients. A repeat soil test a year or 2 later, from identical sites, will allow you to adjust your fertiliser needs.
Hint: Get quotes before getting soil, and herbage tests done. Some
businesses are far more expensive than others. |
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Nitrogen (N):
Nitrogen which is taken up rapidly by plants, helps the grasses build up leaves quickly. If spread by the farmer it is usually in the form of urea. A nitrogen deficiency is shown by the yellowing of grass leaves. Animal urine is high in nitrogen.
Potassium (K):
Potassium improves the quality of the grass, and its resistance to drought and disease. A yellowish pasture is a clue to potassium deficiency. Extremely potassium deficient pastures will have clovers with holes in their leaves. Grasses tend to absorb more potassium than required. Pottasium is returned to the soil in animal urine. Vigorous clover growth in urine patches is a sure sign of a potassium deficiency.
 Urine patches clearly visible in a paddock
Phosphate (P):
Phosphate will stimulate root development and plant growth. As the Olsen P (a measurement for phosphate soil levels) increases, so does clover growth, and with the clover growing well, more nitrogen is available for grasses, and the grass grows well.
Sulphur (S):
Clover growth is very dependant on sulphur. Deficient plants appearing pale green, or yellowish. Clovers will appear sulphur deficient before grasses.
Calcium:
Calcium is related to soil pH. Lime is applied if calcium is deficient. Clover leaves will be smaller than normal in clover deficient soils.
Calcium is important for soil structure by mixing clay and humus into granular soil particles. In plants, calcium is required for cell membranes, and cell wall systems, plus in fine roots for mineral absorption, and for sugar transportation.
Magnesium:
Magnesium is essential for photosynthesis. Magnesium regulates the passage of phosphate with in the plant. Magnesium deprived plants will appear yellowish.
At least 14 elements are supplied by the soil for plant growth.
Hydrogen, oxygen, and carbon are required also, but the environment supplies these.
Soil micronutrients:
Are needed in tiny amounts for plant growth. Grazing animals depend on plants to supply them with these essential micronutrients.
They are: boron, molybdenum (essential for clover growth) chlorine, iron, manganese, zinc, copper, & nickel. Some plants also need sodium, cobalt, vanadium, and silicon.
If tests such as herbage, soil, animal organ biopsy, or blood test suggested that a micronutrient is deficient, consult a vet, or soil scientist, because an abundance of one micronutrient can be detrimental to soil or stock health.
Boron (B):
Is needed for effective plant calcium uptake, plus root strength, the growth of
new cells, nodule formation in legumes, and the regulation of carbohydrate
metabolism.
Cobalt:
Is needed by nitrogen fixing bacteria, and by grazing animals.
Copper (Cu):
Is required for the metabolism of proteins and carbohydrates. It is needed for nitrogen fixation by rhizobia bacteria. It is involved in the conversion of sunlight to plant energy.
Iron (Fe):
helps prevent plant "die back". It increases plant strength. It operates the respiratory system of plants.
Manganese:
Is required for the metabolism, and assimilation of nitrogen and for photosynthesis. It is also needed for rapid plant growth.
Molybdenum:
Is needed for all living processes. In agriculture it is needed for the proper utilisation of nitrogen. Legumes require more Mo than non legumes. Molybdenum deficiency in plants is shown by stunted growth, and lack of vigour.
Selenium:
is essential for mammals, where it's presence has been known to improve fertility. It can prevent deficiencies associated with Vit E. Selenium deficiency in stock causes white muscle disease.
Sodium (Na):
This increases the yield in plants. Animals need sodium.
The pH scale:
This scale goes from 1-14. Neutral having a pH of 7
An acid is less than 7 (a strong acid has a low pH)
An alkali is more than 7 (a strong alkali has a high pH)
The recommended pH varies with different soil types.
Lime:
Lime is applied to increase the soil pH. Increasing the soil pH will lead to increased water absorption in the soil, and then lead to increased worm populations.
Over liming:
This can create soil mineral deficiencies. Heavy soils can also become waterlogged.
Fertilizer is needed for soils because:
Soil
fertility is lost by: Leaching, stock grazing, (although they
replace some through urine and dung.) Hay and silage, where the
fertility is carted off the paddock, and a "shut up" paddock is deprived
of animal dung and urine. You replace some fertility when feeding out.
Fertilisers:
http://en.wikipedia.org/wiki/Fertilizer
Fertiliser needs depend on:
Your soil type, farm management, and stocking rate, type of farming.
Pasture based Dairy farming depends on soils with a high fertility. This
leads to more grass being grown, and with more grass the farmer can feed
more cows.
Fertilisers:
These are available in different forms: powders, granules, prills,
slurry and liquid. Your choice of fertiliser and the character of your
land will influence the method of spreading.
Truck and Spreader:
Is the most common way of spreading dry fertilisers. |
Soil, and herbage tests:-
Provide you with the information on the
nutrient needs of your soil .
Re taking your sample:
Avoid urine, and faecal patches.
Make a note of where you take your soil samples from..
By doing a repeat soil test ( 1 or 2 years later) in the same place as the first
test, you will gain
a knowledge of your soils losses, and needs.
http://www.soiltestingservices.co.nz
http://www.agconsult.co.nz/tests.html
http://www.soiltech.co.nz/
http://www.hill-laboratories.com/
http://www.wiseearth.co.nz/
Australia:
http://www.soiltestingaustralia.com/do/t/soil
http://www.hotfrog.com.au/Products/Soil-Testing-Service
A further check on animal health can be done by getting a liver biopsy done on
animals you are about to cull.
Ask the vet about this.. If the vet agrees that there is merit in a liver
biopsy, they can organise it.
Liquid Fertilisers:
Need a boom spray, and tank. These can be attached to an ATV's, a truck, or a helicopter.
Aerial Topdressing:
"Top dressed" by plane. For hilly land. Or on waterlogged paddocks.
Note when Applying Fertilisers:
If applying fertiliser after heavy rain, the weight of a truck, and the wheels can cut up your paddock.
You'll need to consider the rotation of your stock when applying fertiliser. Some paddocks should not be grazed for a fortnight after applying some fertilisers. Other fertilisers are dependant on heavy rain, and should NOT be grazed until the paddock has had a good wetting.
Don't apply fertiliser during a drought.
Make sure spread/sprayed fertilisers don't get into creeks, rivers, lakes.
Notes on some Common Fertilisers:
Reactive phosphate Rock: This fertiliser needs a high rainfall, and acid soil. It is a slow release fertiliser (3-4 years) Sulphur, if required needs to be added separately. Suitable for fertility maintenance only.
Long Life:
This is a combination of super phosphate and reactive phosphate rock. Only the superphosphate (70%) will be released instantly for plant use.
Superphosphate:
Commonly called "super", or "phosphate". It is a popular choice for fertility maintenance, and for those wishing to increase their phosphate levels. It is a water soluble, plant available, rapid release fertiliser. It does not contain nitrogen.
Potassium Fertilisers:
Ideal for increasing soil potassium levels, but don't apply just prior to calving or lambing. (high plant potassium can predispose stock to milk fever and hypomagnesaemia).
Ideally; spread 6 to 8 weeks after lambing and calving.
Increasing Potassium levels can be done by adding KCL (Muriate of Potash) to other fertilisers.
Charts are available with the varieties of fertilizers, and the nutrients they supply. Ask the representative from your fertiliser company about your needs. He can identify your requirements, plus the area you need to
fertilize, and the total amount of fertilizer you need.
Urea:
Urea is a plant available form of Nitrogen. Many farmers use urea to
enhance pasture growth.
If grass growth conditions are ideal (sunlight, warm soils, and moisture) expect a rapid grass growth after a light spreading of nitrogen. Urea will leach from the ground, eventually damaging rivers, lakes ect.
The idea is to use nitrogen only if pasture feed is short, or for saved pastures when grass growing conditions will stall rapid grass growth, eg on late autumn pasture saved for winter grazing.
Urea and macronutrients:
These combinations are popular, because they save spreading costs. Time the application to fit in with your management, e.g. early spring, so you have plenty of feed for lactating animals.
Liquid fertilisers:
The stoma on the leaves of the plant rapidly take in the nutrients. The nutrients are
then translocated through the plant. Sprayed on fertilisers dose both the plant and the soil.
Plasma:
This has the essential NPK's, plus a concentration of minerals and pasture growth enhancers. It can be mixed to suit particular pastures, or as per your soil test. Plasma ingredients act/contribute to the health of soil.
Plasma Humus:
This fertiliser works by increasing humus, and the biological activity of the soil. The humus, with its micro organisms added to the soil helps plants resist parasites. The humus makes macro, and micronutrients available to the plant. Humus rich soil has great absorption abilities, and leaching is minimal, if at all.
Superphosphate and our soils:
The use of superphosphate has been under debate. A study found that earthworm numbers, and soil organic matter had increased following repeated superphosphate applications. The findings were similar to organic farms. They found that by withholding fertiliser applications the soil microbial populations were reduced.
Learn more by experimenting in your own garden. http://www.fertresearch.org.nz
Fertiliser companies in NZ:
Ploughing:
Ploughing is frequently done prior to planting new grass or crops.
The old pasture, or crop is turned over and the "old plants" become part of the organic matter in the soil.
Soil Compaction:
This is the result of heavy weights on soggy soils. Cattle hooves, mashing up the sodden ground, and bike, tractor, truck wheels are the main culprits. The pugged ground looses its bounce back, as soil particles become squashed together.
When this soil dries up it is very hard. Some plant roots will modify themselves to cope, but usually plant populations will be reduced. If large areas become compacted: (a.) Remember to take care of your pasture in future. (b.) Plough then resow the paddock. (c.) Soil aeration. This is done when the soil is not too wet, or too dry. Employ a contractor, to use an "aerator", a large machine that 'busts' up the tough soils without damaging plants. Aeration allows the soils and plants to breath, which results in better root and plant development.
The damage (above) was caused by a
herd of cows plodding through waterlogged soil.
Cow's hooves act like potato mashers when
the soil is so damp.
Soil Erosion:
Soil erosion is a problem world wide. this happens on hilly area..
Water Erosion:
Steeply sloped land, even if planted in pasture can slip away when soils are very damp.
The rain may wash away organic matter from the soils, and there will be limited water holding ability.
Wind Erosion:
Bare Land, especially a newly ploughed paddock!!, or anywhere where unprotected soil is exposed to the wind..
The wind also dries the soil.. As the wind continues, the soil, now like dust particles becomes airborne
If you want to re-grass paddocks that are exposed to the wind, then choose to
spray them to kill existing plants, (herbicide) first, then direct drill
them. Other wise the wind will lift, and distribute your valuable
topsoil around the neighborhood.
Prevention of soil erosion:
Plant trees for shelter to reduce the impact from the wind. Plant also trees surrounding areas that have previously slipped away.
If you can, increase the soil fertility, which will increase plant growth, and root anchorage.
GLOSSARY
Aggregate:
a lump of soil particles all stuck together.
Alluvium:
Fertile soil consisting of mud silt, and sand deposited by flowing water.
Biota:
(soil) A collection of micro and macro organisms that break down organic matter in the soil.
Dentrification:
Soil micro organisms can convert soil nitrate to nitrogen gasses, (which are lost in the atmosphere) under waterlogged conditions when organic matter is present.
Friable:
Easily broken up. Easily crumbled.
Humus:
A mass of partially decomposed plant, or animal matter in the soil.
Humic Acid:
A soil mineral mobilising agent, which aids the plant to feed from soil nutrients. It helps build larger root systems, and better soil conditions.
Leaching:
eg nitrogen. is "washed down" Nitrogen is quite mobile in a soil solution.. Nitrogen can find its way to waterways!!
Loam:
Fertile soil consisting of sand clay, and decomposing organic material.
Organic Matter:
Decaying plant and animal matter in the soil.
Olsen P:
Soil phosphorus level. The measurement.
Pasture renewal:
Replacing the old pasture with newer more vigorous pastures to increase productivity.
Porous, porosity:
Allowing liquids and air to be absorbed.
Stoma:
A pore in the plant leaf that controls the passage of gasses into and out of the plant.
Subsoil:
A layer of soil underneath the top soil.
Texture:
(soil) The proportion of sand, silt, and clay making up the mineral component of the soil.
Top Soil:
The top layer of soil.. Where most of the organic material is found.
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