Soil salinity in Australia (2001)


[Music plays] (Narrator) Salt — white death. All over Australia it’s
rising out of the ground and destroying our farms,
homes, and towns. To understand why we
have this problem we need to go way, way back
in Australia’s history. Australia was once part of a huge
super continent called Gondwana. It was joined to Antarctica,
India, Africa, and South America. Since then a lot has happened to
the land that became Australia. During a severe ice age part of
it was covered by an ice sheet. As the ice moved across the land it
ground up rock to make new soil. It was the last time new soil was
made that way in this continent. Later, India broke away. The climate was much
wetter than today, and parts of Australia sank under
the weight of river sediments. Still later, when the sea level rose,
a lot of the land went under water. Then the east coast tilted up when it broke from the New
Zealand subcontinent, and at the same time parts
sank, and continued to sink. When Australia finally
broke free of Antarctica, large areas were still sinking. One of those areas forms the
Murray Darling River Basin, which is the site of our biggest
river system and major farming lands. Today the sinking continues, and Australia is shaped like
a giant shallow saucer. If you look at a cross
section from east to west you can see that Lake Eyre, near the
centre, is well below sea level. This means that rain falling on much
of the country drains inwards. For millions of years clouds have
dumped salt on the earth in rain. Because of the shape
of the country the salt hasn’t been able
to get back to the sea, it’s had nowhere to go
but into the ground. The water that took it there forms a
layer of salty underground water. The top of that layer is
called the water table. Australia’s native vegetation has evolved in harmony
with the water cycle. Many trees and grasses
are deep rooted, so they can take up most of the
rain that falls on the ground. Because they grow all year there’s
no time that water isn’t soaked up. Not much water gets through
to the groundwater below, so the water table stays at
pretty much the same level. We’ve disrupted the water
cycle in two ways, by clearing vegetation, and by pouring more water on the
land when we irrigate for farming. When European farmers
cleared the land, they planted shallow rooted crops
that grew for only part of the year, taking up a mere fraction of
the water falling as rain. The excess water moved
down to the subsoil. Eventually the water table rose,
bringing salt to the surface. This salt kills most plants, and
makes it impossible to grow crops. Without plant roots to
hold the soil in place the soil washes or blows away,
terrible erosion results. [Music plays] One of the ways to reverse the problem
is to plant deep rooted trees, grasses, or crops that can suck
up the water out of the ground. This will lower the water table and allow the salt to go
back down into the ground, below the root zone. Irrigation presents
another problem. Many of our crops are grown using
water that’s poured onto the land. Water seeps from
irrigation channels and from over watered crops
into the water table. It’s important to add just
enough water to the soil to grow the plants,
because any extra water causes the water table to rise. Every year Australia loses large
areas of farming lands to salt. If we don’t turn this
situation around quickly we’ll have difficulty
feeding ourselves. We need to change our land use
patterns, and start gaining income from the native plants that
grow so well in our landscape. [Music plays] It’s not only plants that
are affected by salt. Homes across Australia are crumbling as salt eats away
at the foundations and walls. Houses built to last 25 years
are surviving only two years. By growing native trees
and shrubs around homes, and reducing the
size of the lawn, the need to water the
garden can be reduced. This stops water seeping
into the water table. Roads, too, crumble
when attacked by salt. Roads need four times the
amount of maintenance where water tables are high. Playing fields, footpaths,
swimming pools, and the whole infrastructure of towns
and cities, is damaged by salt. We’re all in this together. Australia was made rich from the agricultural exports
of the last two Centuries. The wealth in the
towns and cities flowed from government initiatives
to clear and use the land. History has caused the problem we
face — the future is up to us. [Music plays]

27 thoughts on “Soil salinity in Australia (2001)

  1. watching this after I gave the weeds in my garden a salty shower of 8 kg kitchen salt. Hopefully the grass will just look like in the video in couple days

  2. kill me i'm using this for an assignment and my fucking parents will not shut the fuck up!!!!!!!!!!!!!!!!!!!!!!!!!

  3. Grow Palm Dates around/in your farms and houses.
    1. They can tolerate high salinity
    2. They have deep roots (up to 100m)
    3. They use massive amount of water
    These result in control of water table and rain will take the salt back down.
    + you get one of the healthiest and richest fruits in the world.

  4. A very serious problem. Costs us 1/2 billion in lost production every year and getting worse. I am amazed that the commenter's voice was so calm, considering the disaster that continues to unfold and worsen to point of irreversibiity. After 5% soil saline saturation, nothing wil grow, and the soil is infertile forever.

  5. Ever just wonder if all guys just nutted on the same spot? What would it look like? What would it smell like? What would it create?

  6. "Salt — White death…" A little far, ey? Also, this has nothing to do with what we have in school but eff it! We gotta use it anyway!

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