GCTV19: Clay spreading research uncovers keys to improvement of sandy soil.


GCTV19: CLAY SPREADING Narrator: Darryl Anderson
Digging deep into WA’s sandy West Midlands to retrieve tonnes of clay-rich subsoil Graham White: grain grower West Midlands W.A.
Putting on the clay is, we just call it a no brainer. Narrator:
Growers in western and southern regions where sandy soils prevail across millions of hectares,
know that clay changes soil texture including its capacity to hold water. Graham White:
The biggest thing with the sand is the non-wetting and also erosion like wind blowing it away,
so the 4 to 5 inches we’re trying to fix that problem. Narrator:
GRDC and DAFWA are conducting a number of clay spreading trails in Badgingarra Moora,
Meckering and Esperance. The trials are applying science to update
the practice of clay spreading to determine how much clay and how to incorporate it economically,
to overcome water repellence and gain the greatest benefits for farming systems. Steve Davies: DAFWA
The clay helps overcome the water repellence by basically we’re adding more clay to that
soil so we hope to see when we measure that water repellence trait that it’s actually
declined with the claying process, but we also want to see top spoil become more stabilised
and want to see better crop establishment and crop yields. Narrator:
The rate of clay spreading and methods of incorporation are key to the trial. Steve Davies:
We’re trying to add enough to get up to at least 3 or 5 % of clay which basically is
the level that we know overcomes the water soil repellence.
The way we will incorporate the clay here is the site will be deep ripped and that will
start the incorporation process and then one of the implements we’ll use will just be a
small set of off sets discs and that’s really just incorporating the clay into the top 10
centimetres. And then the other implement we’ll use is a rotary spader and they’re really
good for incorporating clay almost down to 30 cms so they can actually incorporate high
rates of clay quite a bit deeper. Narrator:
A simple field exercise illustrates the potential in these stubborn sandy soils. Steve Davies:
Yeah so you can see here this is the problem, this water is sitting here beaded on the water
repellent soil going nowhere and if you don’t do anything about this problem it will always
just stay there. So this is an area where we’ve applied some
clay and we’ve just incorporated it by hand initially here and just showing how the water
actually infiltrates better once it’s got that clay in the soil and helps overcome that
water repellence problem. Narrator:
Clay should be tested before application and then tonnes of clay are required so it’s important
for time and cost that the supply is close-by. Steve Davies:
Often the costs are anywhere from a $100 a hectare depending on the tool being used.
Right up to $200 a hectare just for that incorporation process. Narrator:
Graham White’s convinced it’s worth the effort and expense. Graham White:
Since we’ve put on clay we don’t have any blow, we have a lot less wash from thunderstorms
and great germination that’s the biggest thing we’re getting crops out of the ground, we
got heaps more pasture, yeah it works well. Narrator:
Managing the sites after claying is crucial to the overall success. Steve Davies:
The key thing is just getting the seeding process right and that’s just being careful
in terms of sowing a cereal cover crop and actually just getting the seeding depth right. Narrator:
But caution’s required to achieve a fine balance which is what this trial is all about. Giacomo Betti: DAFWA
We know that we can have problem having too much clay because we can have increased loss
of water through evaporation and also less water available to plant because of the excess
amount of clay. So here we’re trying actually to find the right combination between clay
rate and incorporation in order to tune the most effective option that also increase crop
yield. Narrator:
The researchers are keen to provide early results based on crop establishment this season. Steve Davies:
We’ll be able to look at whether the clay’s impacted on nutrient uptake over this year
and crop growth, and then we’ll actually be getting yields this year and see if clay and
the incorporation methods themselves have had an impact on the grain yields. Narrator:
The payoff to the expense and time, is that with the right clay, clay spreading is a one-off
and very long term solution. Steve Davies:
The evidence we have from what growershave done in SA have done is that the benefits
can last decades even up to 30 years or more. So it’s almost a permanent solution certainly
in our lifetimes.

12 thoughts on “GCTV19: Clay spreading research uncovers keys to improvement of sandy soil.

  1. China has discovered a plant fibre that when mixed with sands makes its absorb water and its makes the deserts green and productive,its was the works of agricultural students.The problems with most landscapes is its flat and harden after millions of years of erosions,Hill terracing and digging swales can changes the dry lands into fertile land by forcing rain water into the underground.

  2. u need to add organic materials or compost. clay is good, only when it is moist. after it get dried up, it get hard like a brick. so, the question is… how are u going to make sure it clay+sand mixture doesn't get dried up under the hot sun.

  3. Sand seems to rise to the top after heavy rains/irrigation. It seems to me the clay will sink further and further into the sand and the sand will rise up into the topsoil meaning clay would have to be added as often as compost or the topsoil will turn sandy again. If only there was a way to pulverize grains of sand into super fine particles then it would become silt or clay like .

  4. I have been promoting rototilling, or like you mentioned rotor spading, get as much compost into the soil as possible, it all acts like a sponge type material slows water percolation, retains water, , decays, builds the soils with microbes, earth worms, aerate the soil, they eat compost, and deficate as well which is N- Nitrogen, equals free nitrogen year in year out,  roto till and roll in one pass, like use your crimper,

  5. Interesting, i always thought the problem with sand was it would not retain water (gravel like properties), had no idea it actually creates a water repelling layer.

  6. Have you looked into the liquid nanoclay approach that these guys are promoting? https://www.youtube.com/watch?time_continue=6&v=stc5MUIloP0

  7. Sand + clay make a great brick. Man you are discarding the lichen paste, the Chinese cellulose paste, liquid nanoclay and petroleum mulch. All of which had given amazing results.

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