Maximising yield potential by minimising soil constraints


GRDC’s Soil Constraints West has been a
five-year collaborative project to identify and address major soil
constraints that limit crop production. The aim to increase soil health and
profitability for growers. While the long range research has been based in Western Australia’s Grainbelt the findings can be applied across Australia’s southern
cropping regions. And we’ve got projects looking at soil acidity, soil compaction, water repellents and then other subsoil constraints. A project focus has been to
encourage growers to identify and respond to this soil constraints the
message dig deeper literally because constraints such as compaction can be up to 50 centimetres underground. I think the first thing that growers have to
have to do is identify and diagnose what the situation is now whether that’s
talking to people like us or talking to their consultants that digging a hole
definitely having a look finding out where the roots have gone. All of those
things are vitally important. Across all soil types and regions costs of
constraints equate to around $100 per hectare and the estimated total cost is
staggering. It’s over a billion dollars when you put it all together in a in
each year and the difficulty with actually calculating a single number is
that we often have these constraints that are more than one together and
we’re looking usually at solving individual constraints. And in WA’s grainbelt there are often there are often multiple constraints interacting, that prevent or inhibit crop growth. For example improving root growth
by ameliorating subsoil acidity with lime is beneficial however that benefit
can be enhanced if subsoil compaction is broken up. Earlier research and soil
sampling projects highlighted the value of soil testing to depth. That awareness
is being built on by the Soil Constraints West project to help manage acidity which is widespread and a production risk. If we’re looking at the soil acidity projects for example there’s a good recognition that the lime,
and a lot of lime that has been applied to manage acidity is still in the
surface, and that lime needs to be mixed through the surface needs to be put into
contact with the acidity that’s deeper in the profile. The current project has confirmed a strong demand by growers for information about soil management.
There’s still more to learn in some research areas such as deep ripping, lime
application, and managing water repellence. But there’s been strong
take-up on many initiatives despite the added work load on growers adopting new practices. What we’re doing is improving the soil to a point where we’re maximising their productivity, maximising their profits that they can they can achieve. Five years on and GRDC’s thirty three million dollar research investment is paying off. Growers are trying different techniques including strategic tillage using modified or different plows and controlled traffic
farming systems to reduce re-compaction. New information tools have also been developed by the project. We have one called ROSA which is ranking of soil amelioration techniques
or methods that helps growers understand what might be the best way to apply some of the amelioration treatments. We have a controlled traffic farming calculator
which again helps them understand how much of the paddock is being trafficked
and how to reduce that and then we also have a lime calculator which is going to
be released shortly which will be looking at incorporation of lime and the
returns from managing acidity. A number of soil quality ebooks are available covering soil management, organic matter and acidity with more to come in the
series. For this last period of these projects we we have Jenni Clausen who has come on board in the extension role and she will be helping us across all of
the projects not just us all acidity project.

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