A grower’s approach to overcoming non-wetting soils


Through my involvement with the local
grower group the Corrigin Farm Improvement Group, I got to witness some
fairly dramatic responses with mouldboard ploughing on a neighboring
property who was addressing non-wetting soils and weed issues. So I attempted to
replicate those results here by doing my my own trials and found that we’re
getting quite large yield responses from mouldboard ploughing, at the same time
we’re burying a problem weed seeds herbicide resistant weeds at depth where
they couldn’t make it to the surface and that was how we started this journey of
mouldboard ploughing. Back in 2013 we ploughed approximately
30 hectares. We ploughed some heavier clay based soils and that
created some establishment issues. However on the right soils that year we
saw some dramatic responses in both yield and also weed control. So from
there that really gave me the confidence to invest in my own plough. I made contact with a machinery dealer in England and arranged a plough to be shipped out in a
shipping container with parts and that cost me approximately twenty thousand
dollars all up. Had I bought a new plough in Australia, equivalent size player
would have been around $70,000. This is the mouldboard plough which
imported from the UK second hand I think I got a pretty good buy
it’s a seven-run machine some key features of this player which are
important the skimmer plate here which pushes the very top layer the top soil
which contains the weed seeds into the bottom of the furrow which is created by
the main board and the small plate on the end of the main board which helps
totally invert that top soil to 30 centimetres. The other important thing
about this plow is these hydraulic brake arms. We’ve got rocks and stumps below
the surface and that means these boards can break out and return to their
position once they hit an obstacle. Yeah so done our own trials here comparing mouldboard ploughing to untreated, and also deep ripping and over a number
of years and on average we achieve between 800 and 900 kilograms a hectare
yield response in the first year however those yield responses continue on and
we’ve found that we’re still getting responses after three or four years so
the benefits really continue more than one year. So we like to monitor how we’re
modifying the soil profile and one way to do that is to to dig a soil pit and we
can share these results with our farming peers in their local area. In the soil pit here we see an example of the effect of mouldboard ploughing where the
topsoil is buried at 20 to 30 centimetres. In that top soil are the weed seeds which unlikely to make it to the surface from that depth. The new
topsoil is now formerly the subsoil which has higher clay content in it and
is wettable. The other interesting thing here is the topsoil is more acidic than
the subsoil so we always apply lime prior to burying that topsoil and below
this layer here we have the subsoil which includes a mixture of gravel and
clay, which is quite a nice subsoil for root growth. There are challenges we’ve come across
with mouldboard ploughing and some of these include crop establishment. Mouldboard
ploughing creates a very soft seed bed so we can bury seeds to deep in the
seeding process. To address that we’ve been very careful where we place our seed but also increased our our seeding rates by about 20%. The other issue is top soil
has low organic matter levels and being soft as well we have run into herbicide
damage. The other challenge we’ve come across is the on our gravelly shallow
gravelly soils it’s very hard on our mouldboard plough with the ripping action, so we’re now looking at using a different machine on those soil types. Okay it’s an alternative to the mouldboard plough for top soil inversion is to use a one-way disc-plough. This needs to be modified to increase the breakout so we can use a much larger disc than this the original disc. To do this we remove
the hub of every second arm and connect these two arms together we do that right
along the machine and brace the rest of the machine for extra strength and that
does a similar job to the mouldboard plough. Mouldboard ploughing is quite a slow process, we do about three hectares an hour so it’s a longer-term project to cover 70%
of the farm. At the moment we’ve done about a third of the property. It’s
important that the soil profile is wet before you mouldboard plough. So it means that we need to wait for good rains or we do the ploughing on chemical fallowed country where we know we’ve got moisture. So summarising this I found that the
mouldboard plough is probably the most suitable machine for this property for a
majority of the soil types to address a key soil constraint here which is
non-wetting soils. We’ll continue to mouldboard plough across the farm
until we’ve done all the suitable soil types but at the same time we’re looking
at other soil amelioration operations such as deep ripping and the one-way
modified plough. Go to the description bar below for the latest information links and resources.

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