April 6, 2026 • 12 mins
Autumn fertiliser can be one of your largest annual input costs, but with the price of fertiliser on the rise, how can you make sure you are maximising your investment while getting the best results for your crop?
Joining April's Tech Talk is PGG Wrightson Technical Specialist for Soil Science, Dr Jay Howes.
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Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
(00:11):
Welcome to another episode of Blue Shift Diary, but we take
conversations from the farm gatedirectly to you.
My name is Milton Monroe. I'm your host and Pig Wrightson
technical team manager. Autumn fertiliser is often a
farmer's largest annual input cost.
But before you spread any product, it's important to be
(00:31):
very clear about what you want to achieve.
April's Tech Talk offers advice and guidance on how to maximise
your fertiliser budget. So who better to talk to than
Peg Wrightson's technical specialist for soil science,
Doctor Jay House? Welcome to the show, Jay.
Hi, Michael. Thanks.
Thanks very much. Fantastic.
(00:52):
So autumn fertiliser, we've already said it, it, it's a
major spend on farm. Do you want to give me a bit of
an idea around, you know, what is the the normal process and
protocol for a little fertiliserprogramme?
Yeah, well, first of all, I'd probably, I would probably call
it an investment, definitely investing in your farming
(01:12):
system. So it's probably one of the
bigger investments that you willdo during the year.
So it's important that that investment pays dividends and
the way you pay dividends is by good planning beforehand.
So the most important thing is you need sort tests.
You can't, you know, you can't expect to, you know, know what
you're doing if you're not measuring and have some records
(01:34):
about what you're actually trying to achieve.
So you know, sore testing for meis is a is a must in a start and
a good history of sore testing as well.
So let's dive into this before we sort of get into the nuts and
bolts of an autumn fertiliser. Let's talk a little bit about
soil testing because I know thisis a topic that you are very
passionate about. What should farmers be thinking
(01:55):
when they're actually looking toput together a a SAW test
programme for their farm? Ohh, I think probably engaging
the right people. So that would be your, you know,
your local TFR and discuss with them.
I mean, hopefully it's already something that's happening on
farm. So it'll be something that you
would, you would look to do yoursore testing Bishop, it's autumn
(02:16):
fertiliser. Hopefully you've got a good sore
testing regime already in place.Some sort of same, same sort of
season every year. There can be variances and soil
tests. If you test an autumn one year
and spring another, things can slightly change.
So you want to be measuring the same time of year.
And you know, from there you canwork out if you've got a
(02:37):
capital, if you're doing a bit of a capital regime, obviously
trying to build up your chemicalfertility and your soil, you can
track your progress and see how the capital, the capital
programme going. Or have you already got a pretty
good system And you just want tomake sure that what you're
putting on maintenance wise, because just because you put on
X amount last year, it doesn't also necessarily mean that you
put on X amount. You know, that same again
(02:59):
mentality, probably not the right way.
The the best way to spend your dollar is, you know, actually
track things and look at the soil test.
And what about when you you're building a soil test programme?
What do we need to take into account?
Is it just a case of just picking a few paddocks at random
and going and saw testing them? Or do you do transacts or do you
do all paddock testing? There's a lot of different
(03:19):
options out there. What would your advice be to
anyone who's listening and looking to try and optimise this
all testing programme? For me, I think keeping it
simple, so, so that is, you know, if you've got a, if you've
got a dairy units say for example, I'd be looking at
splitting my dairy unit up into different areas.
So most dairy place dairy units have AF1 block.
(03:42):
So I'd be looking to get a test out of a monitor paddock and
then if from blocks, I would test that paddock year on year.
This is going to have usually higher fertility then I would
probably, you know, if you've got some, you know, some rolling
country, maybe maybe take a testout of your rolling country,
couple of tests out of your, youknow, your flat country.
(04:03):
And if you have some, you know, night paddocks or something like
that that you use typically for night grazing, maybe you take a
test out of there. So 4 to 5 tests that you test
the you know the same place on the same transit year on year to
build up a good idea of your of the chemical fertility in your
in your soil. Cause it correct me if I'm wrong
(04:25):
here. It's always gonna be a better
thing if we if we're coming froma position of knowledge and
understanding where we know whatour soil fertility is, air
actual recommendations for the fertiliser we use are going to
be much more accurate on the on the money than if we're just
trying to guess where we think we might be.
Yeah, I mean, if if you don't have sortis, we can make some
(04:45):
educated guesses. But like I say, you know, it's
an investment and you want to get the most money back for your
investment. So definitely, you know,
following a prescriptive fertiliser recommendation from
us all test and definitely with that, you know that history is
the most important thing. But I'm able to look back
because soil test variability change year on year.
It's just natural variation. Even if you don't exactly the
(05:09):
same line and the exactly the same pedicure on there, there
will be some natural variation. But if you've got history that
smoothed it out over time and you can get a much better
picture of exactly what you're doing.
And also, you know, your family system may have changed over the
last two or three seasons. Maybe you're stocking at a
higher stocking rate or you're now stocking large.
There's, there's changes you canmake.
(05:30):
And and also from the fertiliser, from the sorry the
saw test, the different productsyou use as well can be different
depending on the numbers that I'd see on a saw.
Test. So let's move more into the
product mix and actually building a recommendation.
So let's assume that we've got our soil tests, we've got a
better history there and we're able to show what our fertility
(05:52):
is across the farm. How do you how do you go about
taking that information and building it into a, into a
fertiliser recommendation? What are you look for as a soil
scientist? Ohh yeah.
So first of all, I'd be be looking for what soil type this
farm is on. Different soils are going to
require different amount of fertiliser.
(06:13):
I mean, if I just take a, a, a very contrasting example, I live
in the manual two. I was in the Taranaki yesterday.
The differences between the exactly the same farming system
are in the Taranaki versus the Manor 2.
It could be up to about three times the amount of P extra
would be needed in the Taranaki versus the matter of two.
So saw type, knowing your saw type and, and how your soil
(06:36):
performs is, is key. So you definitely want to know
your type because it could definitely mark a change your
recommendations as well as that you want to know the optimum
levels 4 for your farm because you know, if your farm's not a
high producing dairy farm, maybeit's just mid produce and you
don't maybe need to run as higher levels as a very high
(06:59):
producing dairy farm. If you're a system 5 versus a
system 1 dairy farm as well, that could also change.
You know, if you're running a system 5, you're not grown maybe
as much grass as maybe a system two or three.
So maybe your fertility doesn't need to be as as high as maybe a
different system. So definitely knowing that the
system as well, if it was cheap and if it was sheep and beef
(07:21):
properties, it would be the difference between is it a
breeding unit? Is it a finishing unit?
How much flats has it got? How much hills has it?
What's like understanding the topography and the layout of
that farm, depending on how muchfertiliser I'd put in different
areas and then tailoring that tono one.
Optimum's where I'd want to get peak production from.
(07:42):
So if everything was sitting where I wanted it to be, it
would be a maintenance and that maintenance would usually come
down to on a chicken, beef unit would come down to stocking
rate, sort of rateable stock units wintered usually, and it
was a dairy unit. It's usually on kg of milk
solids per hectare, you know. Would.
(08:03):
Would would. Change things over, plus also
the soil type as well. Sounds like it's a reasonably
complex sort of process. Yeah, I suppose, yeah.
It's, once you get into it, you know, you do, you know, things
do start becoming familiar. But yeah, when you're doing a
lot of different systems or around New Zealand, yeah, it
(08:25):
does become quite complex because even even two sources
that they say, you know, 2 sealsthat say sedimentary could
actually be totally different farming systems, even though
they're under that broader umbrella of residentiary soil,
they could be two totally different systems that I would
fertilise completely differently.
I'll go back to the very first points you made when you pulled
(08:45):
me up on it right at the very start.
This is an investment for the farm.
It's not a cost to the farm. It's an investment to the farm.
And yeah, it might be complex, but it's worthwhile having that
that thought process through. It, you know, the investment in
some SAW tests, you don't have to, you don't have to change
your fertiliser programme too much.
(09:07):
You know, just just say you, youpay for your test and that's you
works out. You maybe don't need to put on
capital anymore. You may have been putting on
capital for two more years. That's more than paid for those
sort tests. So those saw tests had 100%
worth the money that they pay for whenever I get there
whenever on farm and people, youknow, I'm asking the question,
how can I save? You know, how can I save on my
fertiliser ball? Use my fertiliser bill more
(09:27):
efficiently First, like I say, is shortest.
So what would be your, your practical tips for anyone who's
listening in at the moment and, and you're thinking about, you
know, if there was, if there wasa couple of key points, two or
three key points that you could,you could tell to all the
listeners, what would they be, Jay?
First one would be understand your sore type, know what your
(09:48):
soil type is. Um, understand the unique
properties of your soil. Your, you know, your neighbor
down the road could potentially have totally different saw type
to you. And maybe if you take the advice
of your neighbor or you know, you talk to your neighbor and
they're doing X, you might actually have to do Y.
So it would be definitely understanding, you know, your
soil type. The other one would be making
(10:11):
sure you're listening to the right people.
So definitely you know, you're, you're right since TF up.
That's another one. So get, you know, get the right
advice. And probably the third one.
There is no magic bullets when it comes to fertiliser.
I think we've already realised that it's a, it is a, it's a
complicated process, but it's one that can really unlock a lot
of production when we get it right.
(10:32):
Yeah, for sure. I think one thing that's
certainly coming through with this discussion, Jay, is getting
this right is a really complex scenario.
And, and look, no one expects farmers and growers to be able
to do it on their own. What's the best way for people
to get support? Who can their farmers and
(10:54):
growers go to to get a helping hand when building these
programmes? Well, the first port of call
should be their, their local TFR.
I mean, yeah, their local TFR gets, you know, trainings from
the like it's the likes of our technical team.
So you know, they're well versedin, in soils and fertiliser.
And as well as that they have direct access to, to people like
(11:15):
myself to, to help with this planning stage as well.
So you know, they, they have thebest advice and I would say the
most independent advice in New Zealand on fertiliser.
They look fantastic. Thank you very much for your
time today Jay. Been great to get an update on
this and I will let you go back to to reading some saltist,
looking at some soil types and and planning for the fertiliser
(11:37):
programmes for the future. Thank you very much.
Thank you for joining Blue Shield Diary, a weekly podcast
brought to you by PGI Wrightson.Be sure to subscribe to the show
so you never miss an episode. Gaki Tiano.
Welcome to another episode of Blue Shift Diary, but we take
conversations from the farm gatedirectly to you.
My name is Milton Monroe. I'm your host and Pig Wrightson
technical team manager. Autumn fertiliser is often a
farmer's largest annual input cost.
But before you spread any product, it's important to be
(00:31):
very clear about what you want to achieve.
April's Tech Talk offers advice and guidance on how to maximise
your fertiliser budget. So who better to talk to than
Peg Wrightson's technical specialist for soil science,
Doctor Jay House? Welcome to the show, Jay.
Hi, Michael. Thanks.
Thanks very much. Fantastic.
(00:52):
So autumn fertiliser, we've already said it, it, it's a
major spend on farm. Do you want to give me a bit of
an idea around, you know, what is the the normal process and
protocol for a little fertiliserprogramme?
Yeah, well, first of all, I'd probably, I would probably call
it an investment, definitely investing in your farming
(01:12):
system. So it's probably one of the
bigger investments that you willdo during the year.
So it's important that that investment pays dividends and
the way you pay dividends is by good planning beforehand.
So the most important thing is you need sort tests.
You can't, you know, you can't expect to, you know, know what
you're doing if you're not measuring and have some records
(01:34):
about what you're actually trying to achieve.
So you know, sore testing for meis is a is a must in a start and
a good history of sore testing as well.
So let's dive into this before we sort of get into the nuts and
bolts of an autumn fertiliser. Let's talk a little bit about
soil testing because I know thisis a topic that you are very
passionate about. What should farmers be thinking
(01:55):
when they're actually looking toput together a a SAW test
programme for their farm? Ohh, I think probably engaging
the right people. So that would be your, you know,
your local TFR and discuss with them.
I mean, hopefully it's already something that's happening on
farm. So it'll be something that you
would, you would look to do yoursore testing Bishop, it's autumn
(02:16):
fertiliser. Hopefully you've got a good sore
testing regime already in place.Some sort of same, same sort of
season every year. There can be variances and soil
tests. If you test an autumn one year
and spring another, things can slightly change.
So you want to be measuring the same time of year.
And you know, from there you canwork out if you've got a
(02:37):
capital, if you're doing a bit of a capital regime, obviously
trying to build up your chemicalfertility and your soil, you can
track your progress and see how the capital, the capital
programme going. Or have you already got a pretty
good system And you just want tomake sure that what you're
putting on maintenance wise, because just because you put on
X amount last year, it doesn't also necessarily mean that you
put on X amount. You know, that same again
(02:59):
mentality, probably not the right way.
The the best way to spend your dollar is, you know, actually
track things and look at the soil test.
And what about when you you're building a soil test programme?
What do we need to take into account?
Is it just a case of just picking a few paddocks at random
and going and saw testing them? Or do you do transacts or do you
do all paddock testing? There's a lot of different
(03:19):
options out there. What would your advice be to
anyone who's listening and looking to try and optimise this
all testing programme? For me, I think keeping it
simple, so, so that is, you know, if you've got a, if you've
got a dairy units say for example, I'd be looking at
splitting my dairy unit up into different areas.
So most dairy place dairy units have AF1 block.
(03:42):
So I'd be looking to get a test out of a monitor paddock and
then if from blocks, I would test that paddock year on year.
This is going to have usually higher fertility then I would
probably, you know, if you've got some, you know, some rolling
country, maybe maybe take a testout of your rolling country,
couple of tests out of your, youknow, your flat country.
(04:03):
And if you have some, you know, night paddocks or something like
that that you use typically for night grazing, maybe you take a
test out of there. So 4 to 5 tests that you test
the you know the same place on the same transit year on year to
build up a good idea of your of the chemical fertility in your
in your soil. Cause it correct me if I'm wrong
(04:25):
here. It's always gonna be a better
thing if we if we're coming froma position of knowledge and
understanding where we know whatour soil fertility is, air
actual recommendations for the fertiliser we use are going to
be much more accurate on the on the money than if we're just
trying to guess where we think we might be.
Yeah, I mean, if if you don't have sortis, we can make some
(04:45):
educated guesses. But like I say, you know, it's
an investment and you want to get the most money back for your
investment. So definitely, you know,
following a prescriptive fertiliser recommendation from
us all test and definitely with that, you know that history is
the most important thing. But I'm able to look back
because soil test variability change year on year.
It's just natural variation. Even if you don't exactly the
(05:09):
same line and the exactly the same pedicure on there, there
will be some natural variation. But if you've got history that
smoothed it out over time and you can get a much better
picture of exactly what you're doing.
And also, you know, your family system may have changed over the
last two or three seasons. Maybe you're stocking at a
higher stocking rate or you're now stocking large.
There's, there's changes you canmake.
(05:30):
And and also from the fertiliser, from the sorry the
saw test, the different productsyou use as well can be different
depending on the numbers that I'd see on a saw.
Test. So let's move more into the
product mix and actually building a recommendation.
So let's assume that we've got our soil tests, we've got a
better history there and we're able to show what our fertility
(05:52):
is across the farm. How do you how do you go about
taking that information and building it into a, into a
fertiliser recommendation? What are you look for as a soil
scientist? Ohh yeah.
So first of all, I'd be be looking for what soil type this
farm is on. Different soils are going to
require different amount of fertiliser.
(06:13):
I mean, if I just take a, a, a very contrasting example, I live
in the manual two. I was in the Taranaki yesterday.
The differences between the exactly the same farming system
are in the Taranaki versus the Manor 2.
It could be up to about three times the amount of P extra
would be needed in the Taranaki versus the matter of two.
So saw type, knowing your saw type and, and how your soil
(06:36):
performs is, is key. So you definitely want to know
your type because it could definitely mark a change your
recommendations as well as that you want to know the optimum
levels 4 for your farm because you know, if your farm's not a
high producing dairy farm, maybeit's just mid produce and you
don't maybe need to run as higher levels as a very high
(06:59):
producing dairy farm. If you're a system 5 versus a
system 1 dairy farm as well, that could also change.
You know, if you're running a system 5, you're not grown maybe
as much grass as maybe a system two or three.
So maybe your fertility doesn't need to be as as high as maybe a
different system. So definitely knowing that the
system as well, if it was cheap and if it was sheep and beef
(07:21):
properties, it would be the difference between is it a
breeding unit? Is it a finishing unit?
How much flats has it got? How much hills has it?
What's like understanding the topography and the layout of
that farm, depending on how muchfertiliser I'd put in different
areas and then tailoring that tono one.
Optimum's where I'd want to get peak production from.
(07:42):
So if everything was sitting where I wanted it to be, it
would be a maintenance and that maintenance would usually come
down to on a chicken, beef unit would come down to stocking
rate, sort of rateable stock units wintered usually, and it
was a dairy unit. It's usually on kg of milk
solids per hectare, you know. Would.
(08:03):
Would would. Change things over, plus also
the soil type as well. Sounds like it's a reasonably
complex sort of process. Yeah, I suppose, yeah.
It's, once you get into it, you know, you do, you know, things
do start becoming familiar. But yeah, when you're doing a
lot of different systems or around New Zealand, yeah, it
(08:25):
does become quite complex because even even two sources
that they say, you know, 2 sealsthat say sedimentary could
actually be totally different farming systems, even though
they're under that broader umbrella of residentiary soil,
they could be two totally different systems that I would
fertilise completely differently.
I'll go back to the very first points you made when you pulled
(08:45):
me up on it right at the very start.
This is an investment for the farm.
It's not a cost to the farm. It's an investment to the farm.
And yeah, it might be complex, but it's worthwhile having that
that thought process through. It, you know, the investment in
some SAW tests, you don't have to, you don't have to change
your fertiliser programme too much.
(09:07):
You know, just just say you, youpay for your test and that's you
works out. You maybe don't need to put on
capital anymore. You may have been putting on
capital for two more years. That's more than paid for those
sort tests. So those saw tests had 100%
worth the money that they pay for whenever I get there
whenever on farm and people, youknow, I'm asking the question,
how can I save? You know, how can I save on my
fertiliser ball? Use my fertiliser bill more
(09:27):
efficiently First, like I say, is shortest.
So what would be your, your practical tips for anyone who's
listening in at the moment and, and you're thinking about, you
know, if there was, if there wasa couple of key points, two or
three key points that you could,you could tell to all the
listeners, what would they be, Jay?
First one would be understand your sore type, know what your
(09:48):
soil type is. Um, understand the unique
properties of your soil. Your, you know, your neighbor
down the road could potentially have totally different saw type
to you. And maybe if you take the advice
of your neighbor or you know, you talk to your neighbor and
they're doing X, you might actually have to do Y.
So it would be definitely understanding, you know, your
soil type. The other one would be making
(10:11):
sure you're listening to the right people.
So definitely you know, you're, you're right since TF up.
That's another one. So get, you know, get the right
advice. And probably the third one.
There is no magic bullets when it comes to fertiliser.
I think we've already realised that it's a, it is a, it's a
complicated process, but it's one that can really unlock a lot
of production when we get it right.
(10:32):
Yeah, for sure. I think one thing that's
certainly coming through with this discussion, Jay, is getting
this right is a really complex scenario.
And, and look, no one expects farmers and growers to be able
to do it on their own. What's the best way for people
to get support? Who can their farmers and
(10:54):
growers go to to get a helping hand when building these
programmes? Well, the first port of call
should be their, their local TFR.
I mean, yeah, their local TFR gets, you know, trainings from
the like it's the likes of our technical team.
So you know, they're well versedin, in soils and fertiliser.
And as well as that they have direct access to, to people like
(11:15):
myself to, to help with this planning stage as well.
So you know, they, they have thebest advice and I would say the
most independent advice in New Zealand on fertiliser.
They look fantastic. Thank you very much for your
time today Jay. Been great to get an update on
this and I will let you go back to to reading some saltist,
looking at some soil types and and planning for the fertiliser
(11:37):
programmes for the future. Thank you very much.
Thank you for joining Blue Shield Diary, a weekly podcast
brought to you by PGI Wrightson.Be sure to subscribe to the show
so you never miss an episode. Gaki Tiano.
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