Thanks Craig, and thanks to the organising committee for the invitation today.
Obviously, we've come off a wet
year and it's quite topical about what
we can do to try and mitigate the risk
of waterlogging in paddocks that
are prone to that issue.
As an aside, we see waterlogging
effects not just in high
rainfall zones - right from
Queensland right through to Tasmania,
it's a common issue that we see, it's
just often not addressed or it's
considered at a level that's not
worth any investment in
managing, yet hopefully today I can show
you some simple tools that can be used
to implement some strategies to
just mitigate that effect where
it is potentially likely to occur.
I put this up - this is the typical
Precision Ag cycle we take with any solution
we're trying to deliver for for a customer.
I think for me this holds the key to
the adoption of precision ag, generally
speaking, and drainage is a good
example where we can't just be
spinning that data cycle and not really
having any focus on what we're trying to
achieve at farm level, and so it's
about having a targeted constraint,
identifying what data do we need to fix
this issue, what intelligence and
processes do we need to go through to analyse it and
often that's in partnership between our
business and the
agronomists that we work with to
ultimately deliver an action and until
we get an action, there's no value
realized in any of this and therefore
there'll be no reinvestment in
precision ag and so that's where I think there's a
real failing. Generally speaking, it's
between taking it from data right
through to an action in the field and
drainage is just a nice example where we
have identified there's an issue, it's quite
visual, we know that, and the action is
getting right through to putting a
scraper or a grater or razor beds or
whatever it might be into a paddock to
have a genuine solution and an action.
There's a whole range of layers to the
whole range of opportunities
with precision ag, which focus on
two aspects, I think: one is
input use efficiency and that's where
you're typically trying to sharpen
fertiliser applications and right
through to yield unlock and I think drainage is
one of those things where if it's
a constraint that occurs on
your farm, then it's something
we would view that as a yield unlock program
where we can put some steps in place to
mitigate that. We start with the data and
I'll talk about this. EM38 and elevation,
very common data sets that you're aware of -
the elevation data may come from the
farmers' RTK or it may be
something you have to go into the paddock
and acquire and wet season NDVI, a really
good spatial record of identifying where
the effects of waterlogging have
occurred. Couple those together and you
can start to really build an accurate plan for a farm.
Also, we like to feed in some
strategic soil samples in there,
not just for dispersion and
exchangeable sodium levels but I think
that fits into a whole range of other
new nutrition programs as well which I'll
touch on briefly. Then we get to the
actions - that's ultimately
putting in some drains or
variable rate gypsum.
It's all about, obviously,
trying to minimise the concentration of
water in a paddock, and so it's about
healthy soils, improving infiltration
rate and then using drains to try and
control water movement across paddocks.
I truly believe that,
certainly in our environment where we're
farming,
our biggest opportunity is capturing the
upside in those wet years. If we can harness
that and convert those high rainfall
seasons into big yields like last year,
then I think our business is in
good shape - because at the same time
we're implementing all the healthy soil
strategies and minimum tillage and
stubble retention to try and manage dry
seasons, but often we tend to forget
these wetter years and how we can still
maximise benefits in thoses years, so I think
that's where we can often make
our real money in those seasons.
Satellite imagery: you've
probably all seen it, there's
no real tricks to it - it's a good, robust
guide to biomass. In this particular
image here red is low, blue is high.
Whole farm imagery, low-cost options
can give you a really good guide of where
the water's sat across the farm
and is just a good picture to
start visualising, quantifying the extent of
areas. It's often surprising, people say
well, I knew it was wet anyway, but if you go
down and get it into a spatial
mapping program and measure the exact
the area and say well, actually, that
paddock - it wasn't just that little wet
patch through there, it added up to be
12% of the paddock and the cost was X.
It allows you to do some of those
numbers, you've got that forever, it's
a record that you can compare in
other years and so it's always good from
other programs of trying to define
management zones to look at
how does your farm perform in wet years
and dry years, so it's good to add to your library.
As I mentioned, quantifying and then
ultimately we start overlaying that with
other elevation data sets to really get
into some design steps.
EM38 is another application which
obviously is not critical for just
designing where drains need to go, but I
think it's a really nice data set that can
complement the thinking which integrates
soil type variability as well
as slope and and obvious
movement across paddocks based on
elevation, so we like it because we
can then come into a paddock, do some
soil testing and get a feel for
what, in particular,
dispersive nature and exchangeable sodium
levels are in those areas and start
thinking about some gypsum programs.
From that, you can see we can also do
a drainage plan of where these drains may go
and a big part of that is thinking about A-B lines -
not many people like changing
A-B lines and certainly not many like
having multiple in paddocks, but if in
certain paddocks - if waterlogging is a
really big issue - you may need to even
give up some operational efficiency
and you may have to move
away from being along the longest run
and change your direction of run, maybe even
having two different directions in a
paddock to manage water.
It's just a critical part of the design that
people often forget and they'll just put a
drain in and not realize that the
way, particularly in tine machines, it has a
massive bearing on how water moves across the
paddock and you can really work in with
your drains to draw water into your
drains and carry them out safely.
Soil testing: I've spoken about this,
I really think it's a good
baseline data set as well, and there's a whole
range of measurements up there that you can
see, which are relatively stable type
measurements that once you've got it you
kind of only need it once, or
perhaps only every
third or fourth soil testing cycle that you
might go through on the farm.
It just sets up the basic
understanding of your soil parameters in
a paddock for a whole range of programs
and today I'm talking about the drains, but
particularly that phosphorus,
and nitrogen as well, with your PBIs
and organic carbon levels - so, for me,
that's almost like a starting point of
just understanding paddocks and as we know,
there's a heap of commercial
operators out there that can collect this data, not a
lot of cost and as a one-off investment
to understand paddocks, I really do
support that as a good base data set.
Then, obviously,
go and go in with the sampling
equipment. I put that slide in
there just to talk about going down the
profile - we do a lot of surface testing.
I think if we're going to go to
the effort of doing that, get an
intact core and have a look down the
profile as well and start thinking about
those next depths.
We've had some fantastic work done
with Southern Farming Systems and Lisa Miller
looking at pH down the profile, and I
think it just started to get us all to
starts thinking beyond just the nought to ten test
and going down to that next level,
whether they're ten centimetre
increments or along your different
horizons of your soil, but I think investing
in understanding your soils and doing some of these
cores fits in nicely to a whole range of programs
including, for today's topic, gypsum
application. Just on the gypsum,
I honestly think there's a real research need
to better understand the economics of the
gypsum in these different profiles,
because we might do a nought to ten
and we might be OK - we might have a lot of textured
topsoil - but then we come into,
obviously where we are, we have a lot of sodic
subsoils and depth of working
of effectiveness of gypsum and rates
and alternate rates and I speak to
lots of different agronomists and I get lots of
different answers of how they come up with
application rates, and I've looked for a lot
of calculators and I don't see a lot of
really good tools out there to help us
be scientific about how we
determine the gypsum rate, rather than
just ah well, we'll put a ton on the acre
out because that's a gypsum, that's a soil
repair rate that we use. I think we need
to do better than that and I think that
there's a knowledge gap just on that particular topic.
Another example here of overlaying data sets - this is a
yield map with some contour lines and
this is the property we're on, farming, and
we used to get smashed with waterlogging
every year. It would come off those
rocky rises - so these are non-arable areas,
rocky rises - we had really bad ryegrass
through there. Just put in that very
shallow spoon drain, a curved
drain - the next picture shows it,
so this was from last year. You can see we
still farm right through it, and most of the
drains we're talking about putting in are
just shallow spoon drains that you can still
farm through and that's
changed that area.
It's about a three hectare area, south of that drain, where
we were affected by ryegrass and
some years we would get no crop off that at all.
We put that drain in three years
ago and have completely solved
that issue. The cost was
probably $200 worth of
excavator work. I
just think they're simple strategies
that we're talking about doing here; it's not
rocket science and it doesn't really
affect - we farm through it,
we slow down a little bit when we go and
spray through it, but it doesn't really affect us too
much. I think it's a common sense
approach. This is another paddock, again
showing those different data sets - we've
got the elevation map over here you can
see - so this is a crop coming out of pasture,
we're going to crop it this year -
so we'll just put one drain through
here, we've set our A-B line along
here, so we'll feed water down into this
drain, run it down through, out into a
table drain and down into a creek.
This area through here -
essentially it's like a swamp at the moment,
really very poorly, poor productive
pasture and in country where we
should be able to grow five to
eight ton cereal crops, just an absolute waste, and if
we don't put that drain there, it
will continue to be like that. We've
also got the EM38 data set, just to
understand soil type changes across
that paddock - again, coming out of pasture
we've got no spatial measurements of
performance of that paddock, so yield
maps or NDVI, so we've come in there
and we've identified some different
zones and got some very crude gypsum
rates to go out in the
next six weeks and so we've got this
swampy area which is slightly
heavier textured, but also it's been
wet for most of its life - we
need to try and bring that back to life -
and then we've got some genuinely quite
heavy soil further up in the profile
and then two other transitional soils, so
that's the type of program we are
trying to implement and it's very basic,
but I'm still really
uncomfortable about how we come up with
these rates, as I mentioned earlier,
but I
think there's still value in going with
just some estimates of
what we're doing because
essentially that's what everyone's doing, really, from what I can see.
Another example, case
study of a farmer further over near Lake
Bolac, a whole farm. Again, NDVI
in the background - blue it's high, red
is low, showing where waterlogging
was in effect for this last
season. We've got some existing drains,
you can see the
legend there, so some existing drains through
the property, and then sitting down and
identifying firstly where are the
ridgelines, what direction of run do we
take, do we need to intercept some drains, and
then where can we safely deposit water.
They've got some swamps we can put some water on.
There's two points on that
map where we are going to be putting
water onto a neighbor's property, and so
absolutely critical that you've got to go and
speak to those neighbours and make sure
they're happy for that, and ideally
connect that up and get into a safe water
point. Legislation on where you can
put drains in varies depending
on where you are, so I encourage
you to speak to your local
governments and find out in
your area
what you need to do because permits are
sometimes required and certainly
there's legislation to protect a
neighbour from getting flooded out, so
you can't just go and drop a heap of water
onto the neighboring property.
I think it's just part of that whole
catchment and ideally,
communication is the key. We've never
hit an issue. Often, the water's going
there anyway. One thing to say is
you can't change where water ultimately
ends up, you can't put water into
different catchment, so essentially
the water is still leaving the property
at the same point - yes, it might move a bit
quicker so that's something to be aware
of. We saw that with the raised bed
experience where we've increased the rate
of water coming off
paddocks and that can cause issues. One of the
obvious issues could be if you're putting
water, if it's always gone onto a road
and you're now increasing the rate,
you get a heavy rainfall event and
it starts flooding a road which has
never flooded before, and locals are driving on
that road and they hit water at
night and aqua plane and have an accident -
that's worst-case scenario but
there's some really serious
implications of doing this sort of work
and so again, it's just about being sensible
and if it's a large amount of area, you may
need to look at some buffer dams
to slow that rate down to really
protect the whole community.
We've also got another gypsum program there you
can see, based on the EM38, farmer's
knowledge, agronomists' knowledge and those soil
tests that they've been doing.
My final slide is that I
think it's a combination of looking at
both the gypsum and the drains.
Obviously it's also about time of
sowing and nitrogen and all those other things,
having that whole farm or a bit more of a
a holistic approach to managing
water, not just about one or the other.
Speaking to people over the
last few years, I think there's a greater
awareness of role of gypsum
in improving water infiltration
and managing the effect of waterlogging.
Certainly,
we've been doing varied rate gypsum for
the last few years and it's made an enormous
difference - there was one paddock where
we would lose 15% of the paddock
every year to waterlogging
and through a few drains and
some relatively heavy rates of gypsum,
we haven't lost any -
we've essentially got rid of all that
waterlogging effect completely, we're down to
negligible levels and I'm
convinced it's to do with water just not
running off like it used to.
There's obviously those key data, as I've
mentioned, that we need.
My whole approach to farming is that
we want to be making
informed decisions and evidence-based
decisions and this is just another
example - we've just got to compile
this information and make sure it goes
through to an action and get a result - and
when we have that general thinking,
I think the whole discussion
around precision ag and data will
improve, because at the moment often
it's just spinning, it's just data for data's
sake, but it has to be part of
what are the actions, what are the constraints
on your farm that you want to
improve and unlock your yield potential.
Finally, you move into your
paddock plan which, as
I've said a few times,
direction of run is another important
part of it and being flexible and willing to
change your direction of run, because we
have done jobs where that's all we
had to do - change the direction of run,
no drains required, and it's
eliminated the effect of waterlogging on that
paddock, so really important part of the
design program, and those shallow drains
and then gypsum.
That's my summary on PA for drains,
and we've probably got plenty of time for questions.