April 30, 2025 • 8 mins
Plant tissue testing offers farmers and consultants valuable insight into crop nutrient status and helps diagnose field issues when properly conducted. We explain the science behind tissue testing and share practical tips for getting actionable results.
• Tissue testing can help to evaluate nutrient status to understand crop health at various growth stages
• Troubleshoot field issues by comparing samples from healthy and problematic areas
• It is important to sample the correct plant part according to the crop's growth stage
• Mobile nutrients show deficiency in lower leaves while immobile nutrients affect upper leaves first
• Remember to remove soil contamination from samples, especially when checking iron levels
• Tissue tests can help to identify the problem while soil tests help determine corrective actions
• Have a specific goal in mind before collecting tissue samples
• Take both tissue and soil samples when diagnosing nutrient deficiencies
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Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
Jodi (00:00):
And now it's time for a Tiny Byte of knowledge.
Okay, what is three plus seven?
Sarah (00:19):
Jodi, what are you doing with that corn plant?
Jodi (00:22):
Wait, wait, wait, wait.
It's going to give me an answer.
I'm giving it a tissue test.
Sarah (00:29):
You're giving the corn plant tissue a mathematical test
.
Yes, Jodi, that is not a tissuetest.
What is a tissue test?
A tissue test is simply takinga part of a plant and we dry
down that plant part and wegrind it up and we literally
(00:50):
test it to see how manynutrients are in that plant
tissue.
Oh so, jodi, let's get to thebrass tacks here and talk about
the real topic of today's tinybite.
Why would we do a plant tissuetest?
What are the reasons for planttissue testing?
Jodi (01:10):
There's a couple of really good reasons to go out and test
plant tissue, and one of thefirst one is just to evaluate
nutrient status.
Right, so figuring out, at thispart of the growing season,
what is the nutrient content,what is my nitrogen status, what
is my sulfur status?
How is my corn plant or myother crop holding up at this
part of the growing season?
What is the nutrient content?
What is my nitrogen status?
What is my sulfur status?
How is my corn plant or myother crop holding up at this
point in the growing season?
(01:31):
I think really the mostvaluable way that we can use
tissue tests is to troubleshootissues in the field.
Sarah (01:38):
I don't know if you've ever seen situations where you
got a yellow blob in the middleof the field and the rest of the
field is green.
Jodi (01:46):
Absolutely.
Sarah (01:47):
Absolutely.
Jodi (01:48):
Yeah, I mean some of these .
These things just pop up.
Sometimes it's a it's anherbicide issue, maybe it's SCN,
you don't.
Sometimes you don't even knowwhere to start, and so a
fantastic way to help figure outwhat's going on is doing a
plant tissue test, where you'vegot a good plant tissue test
versus a bad plant tissue testfrom that area in the field that
looks different from everythingelse.
Sarah (02:09):
So when you're doing plant tissue testing then just
to emphasize that point whenyou're troubleshooting you are
usually taking plant samplesfrom both the good area in the
field as well as the bad areaand then comparing those results
at the end to see what kind ofdifferences are going on in the
field.
Jodi (02:26):
If you're really confident that okay, I'm looking at a
nutrient deficiency here, thensure you can probably get away
with just doing a good planttissue sample.
If you're trying to figure outan unknown is this herbicide and
you're trying to rule outthings, it's really important to
have both that good and badsample, just so you can compare
those numbers to each other.
Sarah (02:46):
There are definitely some things to keep in mind when
you're out tissue sampling.
First of all, you need to makesure that when you are taking
that plant tissue sample, thatyou are sampling the right part
of the plant for the stage thatthat particular crop is in.
And usually when you're workingwith a specific lab, they're
going to have guidelines as towhat plant part you should be
(03:07):
sampling at different times ofthe growing season.
Jodi (03:10):
Let's think back to a couple of tiny bite episodes ago
and which we'll link it out inthe show notes.
But, like we talked in theepisode, plant nutrients can be
mobile or immobile and so ifwe're looking at nitrogen at the
seedling growth stage of corn,if we're collecting from
different parts of that plant,from the lower leaves to the top
part of the leaves, thenutrient content in each of
(03:31):
those individual leaves thatyou're collecting from different
parts of that plant, from likethe lower leaves to the top part
of the leaves, the nutrientcontent in each of those
individual leaves that you'recollecting from the top of the
plant to the bottom of the plant, is going to vary.
Sarah (03:38):
Absolutely so.
For example, nitrogen, a plantmobile nutrient, and so the
deficiency symptoms show upfirst at the bottom of the plant
.
If you sample that lower planttissue on that plant, you're
going to have less nitrogen inthat concentration than at the
top of the plant.
Inverse, if you were to be inan iron situation where you've
(04:00):
got an iron deficiency situationgoing on, that is a plant
immobile nutrient.
In other words, the deficiencysymptoms show up first at the
top of the plant and last at thebottom of the plant.
So if you sample at the top ofthe plant and last at the bottom
of the plant, so if you sampleat the top of the plant you're
going to have less iron in thatplant tissue than if you're
sampling at the bottom.
So you need to know at whatcrop stage you need to be
(04:21):
sampling what part of the plant,because we do have a standard
set of plant tissue analysismethods and they are calibrated
to be working with specificplant parts at specific crop
stages.
Jodi (04:34):
And this is kind of a nerdy aside speaking of iron
tissue testing, when you'resampling, like, say, if you ever
wanted a tissue sample for irondeficiency, just keep in mind
that there is a level of iron inall the soil right, and so if
you ever get any sort of soil onthose leaf tissues, that can
affect the results.
Sarah (04:52):
It's a great point, Jodi, because when you select that
plant tissue to be submittingfor iron, you should really try
to brush that soil off as muchas you possibly can.
When I was in a researchsituation, we actually had
protocols for actually washingthat leaf tissue.
Obviously, we don't have theluxury of carrying around a
five-gallon bucket with usthrough a half section, so
(05:13):
that's always an interestingsituation, right?
It's really important to makesure that you get as much soil
off of that as possible, and Ithink it goes to remind
ourselves that tissue samplingit isn't necessarily indicative
of an exact quantity of thenutrients that's in the plant.
It is really an indicationabout whether you are dealing
(05:33):
with nutrients in a sufficiencyor a deficiency situation.
You can't use plant tissuesample results to determine the
amount of fertilizer that ittakes to correct a nutrient
deficiency in the field, but itcan tell you if what you're
looking at is in fact a nitrogendeficiency or a potassium
deficiency or an iron deficiency.
(05:55):
It'll help you narrow down whatyour problem is and from there
you might need more informationto help determine what you need
for that corrective action.
Jodi (06:03):
Yeah, absolutely.
It's so important to have agoal in mind of what you're
doing with the tissue test.
You're going to find out thatthe data that you get doesn't
have a whole lot of value ifyou're just going out to the
field and collecting a tissuesample.
What are you doing with thattissue sample?
Are you trying to evaluatewhether or not you need to apply
additional nutrients?
Are you trying to diagnose aspecific issue in one part of
the field?
(06:24):
It's really, really importantto get specific on what you're
trying to do.
And so, with Sarah's example,right, like, if we're going to
go out and figure out, if try tofigure out if we're deficient
in nitrogen, we might want toalso, at the same time that
we're collecting that good andbad tissue sample, to take a
good and bad soil sample withthat so that we can figure out.
(06:45):
Okay, if I get back with adeficiency for nitrogen in this
tissue in my bad sample, thatsoil test will tell me how much
additional nitrogen I'm going toneed.
Sarah (06:58):
Your tissue sample is going to tell you what the
problem is and your soil sampleis going to tell you what the
corrective action is that youneed.
Furthermore, if you take thatsoil sample from the good area
and the bad area, it's going toreinforce what your tissue
sample results are.
Jodi (07:12):
So when you want to go out and take a plant tissue sample,
remember to have a goal in mind.
Look at the instructions on thebag, make sure you're
collecting the correct part ofthe plant and then have an idea
of what you want to do withthose results once you get them
back.
Sarah (07:27):
And if you are trying to troubleshoot an issue going on
in the field, make sure thatyou're pulling samples from both
the good area and the bad area.
Jodi (07:35):
All right, you should know now what three times seven is.
Sarah (07:38):
Don't ask your corn plant math problems.
That's not going to solve anyproblems.
Just take a good tissue sample.
Jodi (07:46):
Tune in next time for a tiny bite of knowledge from GK
Technology, where we have a mapand an app for that.
And now it's time for a Tiny Byte of knowledge.
Okay, what is three plus seven?
Sarah (00:19):
Jodi, what are you doing with that corn plant?
Jodi (00:22):
Wait, wait, wait, wait.
It's going to give me an answer.
I'm giving it a tissue test.
Sarah (00:29):
You're giving the corn plant tissue a mathematical test
.
Yes, Jodi, that is not a tissuetest.
What is a tissue test?
A tissue test is simply takinga part of a plant and we dry
down that plant part and wegrind it up and we literally
(00:50):
test it to see how manynutrients are in that plant
tissue.
Oh so, jodi, let's get to thebrass tacks here and talk about
the real topic of today's tinybite.
Why would we do a plant tissuetest?
What are the reasons for planttissue testing?
Jodi (01:10):
There's a couple of really good reasons to go out and test
plant tissue, and one of thefirst one is just to evaluate
nutrient status.
Right, so figuring out, at thispart of the growing season,
what is the nutrient content,what is my nitrogen status, what
is my sulfur status?
How is my corn plant or myother crop holding up at this
part of the growing season?
What is the nutrient content?
What is my nitrogen status?
What is my sulfur status?
How is my corn plant or myother crop holding up at this
point in the growing season?
(01:31):
I think really the mostvaluable way that we can use
tissue tests is to troubleshootissues in the field.
Sarah (01:38):
I don't know if you've ever seen situations where you
got a yellow blob in the middleof the field and the rest of the
field is green.
Jodi (01:46):
Absolutely.
Sarah (01:47):
Absolutely.
Jodi (01:48):
Yeah, I mean some of these .
These things just pop up.
Sometimes it's a it's anherbicide issue, maybe it's SCN,
you don't.
Sometimes you don't even knowwhere to start, and so a
fantastic way to help figure outwhat's going on is doing a
plant tissue test, where you'vegot a good plant tissue test
versus a bad plant tissue testfrom that area in the field that
looks different from everythingelse.
Sarah (02:09):
So when you're doing plant tissue testing then just
to emphasize that point whenyou're troubleshooting you are
usually taking plant samplesfrom both the good area in the
field as well as the bad areaand then comparing those results
at the end to see what kind ofdifferences are going on in the
field.
Jodi (02:26):
If you're really confident that okay, I'm looking at a
nutrient deficiency here, thensure you can probably get away
with just doing a good planttissue sample.
If you're trying to figure outan unknown is this herbicide and
you're trying to rule outthings, it's really important to
have both that good and badsample, just so you can compare
those numbers to each other.
Sarah (02:46):
There are definitely some things to keep in mind when
you're out tissue sampling.
First of all, you need to makesure that when you are taking
that plant tissue sample, thatyou are sampling the right part
of the plant for the stage thatthat particular crop is in.
And usually when you're workingwith a specific lab, they're
going to have guidelines as towhat plant part you should be
(03:07):
sampling at different times ofthe growing season.
Jodi (03:10):
Let's think back to a couple of tiny bite episodes ago
and which we'll link it out inthe show notes.
But, like we talked in theepisode, plant nutrients can be
mobile or immobile and so ifwe're looking at nitrogen at the
seedling growth stage of corn,if we're collecting from
different parts of that plant,from the lower leaves to the top
part of the leaves, thenutrient content in each of
(03:31):
those individual leaves thatyou're collecting from different
parts of that plant, from likethe lower leaves to the top part
of the leaves, the nutrientcontent in each of those
individual leaves that you'recollecting from the top of the
plant to the bottom of the plant, is going to vary.
Sarah (03:38):
Absolutely so.
For example, nitrogen, a plantmobile nutrient, and so the
deficiency symptoms show upfirst at the bottom of the plant
.
If you sample that lower planttissue on that plant, you're
going to have less nitrogen inthat concentration than at the
top of the plant.
Inverse, if you were to be inan iron situation where you've
(04:00):
got an iron deficiency situationgoing on, that is a plant
immobile nutrient.
In other words, the deficiencysymptoms show up first at the
top of the plant and last at thebottom of the plant.
So if you sample at the top ofthe plant and last at the bottom
of the plant, so if you sampleat the top of the plant you're
going to have less iron in thatplant tissue than if you're
sampling at the bottom.
So you need to know at whatcrop stage you need to be
(04:21):
sampling what part of the plant,because we do have a standard
set of plant tissue analysismethods and they are calibrated
to be working with specificplant parts at specific crop
stages.
Jodi (04:34):
And this is kind of a nerdy aside speaking of iron
tissue testing, when you'resampling, like, say, if you ever
wanted a tissue sample for irondeficiency, just keep in mind
that there is a level of iron inall the soil right, and so if
you ever get any sort of soil onthose leaf tissues, that can
affect the results.
Sarah (04:52):
It's a great point, Jodi, because when you select that
plant tissue to be submittingfor iron, you should really try
to brush that soil off as muchas you possibly can.
When I was in a researchsituation, we actually had
protocols for actually washingthat leaf tissue.
Obviously, we don't have theluxury of carrying around a
five-gallon bucket with usthrough a half section, so
(05:13):
that's always an interestingsituation, right?
It's really important to makesure that you get as much soil
off of that as possible, and Ithink it goes to remind
ourselves that tissue samplingit isn't necessarily indicative
of an exact quantity of thenutrients that's in the plant.
It is really an indicationabout whether you are dealing
(05:33):
with nutrients in a sufficiencyor a deficiency situation.
You can't use plant tissuesample results to determine the
amount of fertilizer that ittakes to correct a nutrient
deficiency in the field, but itcan tell you if what you're
looking at is in fact a nitrogendeficiency or a potassium
deficiency or an iron deficiency.
(05:55):
It'll help you narrow down whatyour problem is and from there
you might need more informationto help determine what you need
for that corrective action.
Jodi (06:03):
Yeah, absolutely.
It's so important to have agoal in mind of what you're
doing with the tissue test.
You're going to find out thatthe data that you get doesn't
have a whole lot of value ifyou're just going out to the
field and collecting a tissuesample.
What are you doing with thattissue sample?
Are you trying to evaluatewhether or not you need to apply
additional nutrients?
Are you trying to diagnose aspecific issue in one part of
the field?
(06:24):
It's really, really importantto get specific on what you're
trying to do.
And so, with Sarah's example,right, like, if we're going to
go out and figure out, if try tofigure out if we're deficient
in nitrogen, we might want toalso, at the same time that
we're collecting that good andbad tissue sample, to take a
good and bad soil sample withthat so that we can figure out.
(06:45):
Okay, if I get back with adeficiency for nitrogen in this
tissue in my bad sample, thatsoil test will tell me how much
additional nitrogen I'm going toneed.
Sarah (06:58):
Your tissue sample is going to tell you what the
problem is and your soil sampleis going to tell you what the
corrective action is that youneed.
Furthermore, if you take thatsoil sample from the good area
and the bad area, it's going toreinforce what your tissue
sample results are.
Jodi (07:12):
So when you want to go out and take a plant tissue sample,
remember to have a goal in mind.
Look at the instructions on thebag, make sure you're
collecting the correct part ofthe plant and then have an idea
of what you want to do withthose results once you get them
back.
Sarah (07:27):
And if you are trying to troubleshoot an issue going on
in the field, make sure thatyou're pulling samples from both
the good area and the bad area.
Jodi (07:35):
All right, you should know now what three times seven is.
Sarah (07:38):
Don't ask your corn plant math problems.
That's not going to solve anyproblems.
Just take a good tissue sample.
Jodi (07:46):
Tune in next time for a tiny bite of knowledge from GK
Technology, where we have a mapand an app for that.
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