Rob Norton: What are the elements of a good crop nutrition program?

Rob Norton: What are the elements of a good crop nutrition program?

The first and most important step is to
make sure your soil is in good nick. That means dealing with any soil pH issues so
a liming program is the first step on an acid soil, if you’re on a sodic soil
using gypsum to improve soil structure or if you’re on a very depleted
inorganic soil, sand, looking at ways to preserve the topsoil so it’s
protected such as stubble retention. The second thing to attend to is get
your basic agronomy right: sow at the right time, choose the right variety,
makes your weed control as good, get the seeding rates at the right
population density, all those apparently obvious agronomic issues. If you’ve got
those two ticks, those two boxes ticked then you can start thinking about what
are the limiting nutrients those limiting nutrients will depend on how
much water there is or what the yield potential is usually in our soils the
way they are now the most limiting nutrient is nitrogen so paying careful
attention to nitrogen nutrition in terms of managing it in terms of yield
potentials, potential demand, potential removal that becomes a critical aspect
of achieving a good yield so nitrogen. Second thing is to make sure that the
phosphorus and potassium levels are adequate to service the yield potential
that you’re setting up with the nitrogen. After that well you’ll have
specific issues you might have sulphur as being an issue on a light soil or soil
that’s been sulphur depleted low organic materials. Then comes the micronutrients
things like zinc and boron and copper those nutrients can become more
important as we raise yield potential but more generally they’ll appear in certain
soil types so you know there’s 14 essential plant nutrients, you
have to have them all otherwise the limiting one limits yield. In most cases
I’ve said it’s nitrogen, phosphorus is second, some situations potassium and
sulphur will be next in other situations things like zinc or copper
will be limiting so how do you work that out well you’ve got to use soil
tests and diagnostic criteria like tissue tests to help focus your mind on
what those particular limitations are. Things like the Better Fertiliser
Decisions for Crops database helps us identify what are the critical soil test
limits for phosphorus and potassium and sulphur and nitrogen and really
that’s an aggregation of over 6000 field experiments that look to
give us guidance. They’re not the perfect answer there’s no perfect answer because
there’s so many other things other than nutrition other than phosphorus or
potassium supply that affect yield but you know stick to your knitting, get the
basics right and you know, that then allows you to look towards achieving your
water limited yield potential. The better Fertiliser Decisions for Crops database
is this aggregation of 6000 or so field experiments, you can get that
through the website the website which is able to be
interrogated as well as being a place where that information is stored ready
for retrieval. You go back to the question about what do you address in
terms of nutrition. You know the the catch cry I think about is if you hear
foot– if you hear hoofbeats in the middle of the night don’t go looking for
zebras simply because those hoof beats are unlikely in Australia to be caused
by a herd of zebra. In terms of crop management that means think about the
obvious. Address those important nutrient decisions, address soil conditions,
limiting nutrients, nitrogen then phosphorus, then maybe potassium and
sulphur, micronutrients, go for the obvious solutions, don’t try and look for the finer points of
zebras running past your window at midnight.


(1 Comment)

  • Bass Town Ncs

    lovely stuff

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