December 4, 2025 • 45 mins
Tony Mensing and Kapil Arora break down the science behind soil compaction, explaining how equipment adjustments and technology can help manage compaction. They discuss the physical process of soil compaction and its impacts for ag crop production and share practical steps farmers can take to protect soil structure.
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Episode Transcript
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Tony Mensing (00:15):
Hello, and welcome to the Engineering Your Farm
podcast. This podcast isproduced by the Iowa State
University Extension andOutreach field agricultural
engineering team. Welcome backto another episode of the
EngineeringYour Farm podcast.
I'm Tony Mensing, agriculturalengineer with Iowa State
University Extension andOutreach in southwest Iowa, and
today I'm very happy to have Dr.
(00:37):
Kapil Arora, a colleague ofmine, also an agricultural
engineer with Iowa StateUniversity Extension and
Outreach as my guest on theshow. Welcome Kapil, thanks for
being here today.
Kapil Arora (00:47):
Hey Tony, thanks for having me on here today.
Tony Mensing (00:50):
Yeah, absolutely.
If you want to go ahead and givea little more introduction of
your background for thelisteners, that'd be great.
Kapil Arora (00:57):
Yeah, Tony, I've been in extension now for 23
years, I've been serving in therole of the extension engineer
for Central Iowa for all theseyears, and have been covering
about 17 to 20 counties incentral Iowa. And as you know,
we are short few staff. Sotypically that count is higher.
(01:21):
Have been involved in farmlanddrainage, composting, manure
management, and today we arehere to talk about soil
compaction, which happens to bean integral part of all farm
machinery, whether you'redealing with manure issues or
you're dealing with planting andtillage and and all those
(01:43):
things. I do want to point outthat our research lead for soil
compaction is actually Dr.
Mehari Tekeste. He is associateprofessor in agricultural
engineering here, and he's alsothe director for soil machine
dynamics lab here at Iowa StateUniversity. He does work with
(02:06):
different tracks and tires andtesting in his lab, and has
been, has been producing somework on that part.
Tony Mensing (02:19):
Sure. So you have a varied background, as you
described a little bit, but havesome resource knowledge base in
the compaction arena, and Dr.
Tekeste is the lead in that labspace. But we'll have a little
kind of an overview discussiontoday, and hopefully maybe
follow up in some later episodeswith some more in depth in some
of these topic areas that we getdialed in on a little bit today.
(02:42):
So
Kapil Arora (02:44):
Yeah, and that'll be more up the alley for Dr
Tekeste to answer some of thosein depth, detailed scientific
questions. As as you said, youare also in a similar role as
me. So we are more rounded, moremore broad based.
Tony Mensing (03:02):
Sure, yeah, we get to do a little bit of a lot of
different things, and there arecertainly folks that are more
able to dedicate their time to aparticular area. So yeah, we'll
kind of cover some generalthings on compaction today, and
like I said, hopefully follow upin a later episode with some
more detailed pieces down, adown a rabbit hole, maybe, so to
(03:22):
speak, in another area or two,but maybe just kick off today. I
think a lot of people probablyhave a basic understanding, but
physically, what is happening?
What's happening when we have acompaction issue? What happened
in the soil profile?
Kapil Arora (03:36):
Right? So in very simple terms, compaction is soil
particles getting pushedtogether.
Tony Mensing (03:45):
Okay.
Kapil Arora (03:46):
In a uncompacted soil, there is space in between
these particles and aggregates,and we call it the pore space.
This pore space helps to holdwater in it, and also aerates
the soil and also allows theroots to develop through it. But
when you have heavy equipmentgoing over it under unfavorable
(04:11):
conditions, we have morepressure on the soil, and can
come from even lighter equipmentif they are not appropriately
configured. In that case, thatload, or the pressure on the
soil that's exerted downwardsactually pushes the soil
particles together.
Tony Mensing (04:31):
Sure.
Kapil Arora (04:32):
And if the piece of equipment, let's say it's a
tractor, and it's pulling animplement behind it, that
traction force that's needed bythe tractor increases because
it's now also having to havepower for the implement to be
able to do the work. Let's sayit's a vertical till tool
(04:56):
toolbar, or we are just pullinga planter behind the tractor. In
both cases, there are pointsthat are in contact with the
soil, and they are going to needsome draw bar power, which the
tractor has to be able toprovide, but the tractor is
bringing that into play with thetraction it's getting from the
(05:17):
soil surface itself. So as thatforce gets applied on the soil,
that pressure basically pushesthe particles together.
Tony Mensing (05:27):
Sure. So maybe let me recap, and you point out if I
missed something in here, butsoil profile as we think about
it in in this part of the worldwhere we're trying to talk
through production ag growingcrops in Iowa. Here, soil
profile is primarily made up ofthe soil particles themselves,
and then air and water. And theair and water are in that pore
(05:52):
space, as you described, right?
So if we compact that soil,we're reducing the amount of
that pore space that's availableto hold the air in water.
Kapil Arora (06:02):
Very much so. And one way to look at it would be,
if you were to take a corethat's one foot deep and put it
in a let's say we take out arectangular box, so as we see
what that profile is, it's onefoot wide by one foot long, and
then one foot deep, and we canput it in a Plexiglas.
Tony Mensing (06:25):
Sure. We're looking at basically one cubic
foot.
Kapil Arora (06:28):
One cubic foot of the soil, but we are able to put
it in a clear plastic probecontainer, so we can see it on
the side.
Tony Mensing (06:37):
Sure.
Kapil Arora (06:37):
And you can put water on it, and you'll see the
soil is able to hold it. It'sholding that water in the pore
space.
Tony Mensing (06:44):
Right.
Kapil Arora (06:45):
Now, once you bring equipment over it and exert
forces on it, you'll see thesame space getting pushed down.
And now that one cubic foot ofsoil, even though we started out
with one cubic foot, you'll seeit has compressed down on the
top surface.
Tony Mensing (07:04):
Sure.
Kapil Arora (07:05):
It's not the same height, even though it's the
same width and length.
Tony Mensing (07:10):
Sure.
Kapil Arora (07:10):
But it's not the same height. Now the volume has
reduced. Well, physically, wehaven't taken any soil out of
that one cubic foot box.
Tony Mensing (07:21):
Right.
Kapil Arora (07:21):
So it's that pore space that actually is reduced
because soil is giving under theweight it's getting subjected
to.
Tony Mensing (07:30):
Sure, it doesn't have the ability to withstand
that force that's holding theequipment up vertically. Plus,
as you were trying to point outthere the tractors or the
machines themselves, have toapply that tractive effort, that
tractive force, to be able topull the implement behind. So
not only is it supporting theload vertically, it's also
(07:51):
supporting that tractive load.
So we're basically compressing,squeezing that soil to be able
to get that equal and oppositereaction, to be able to pull the
implement plus hold it upright.
Kapil Arora (08:03):
Yeah, very much so.
And that's what that wholeprofile is. It's built of sand,
silt and clay particles, butit's got pore space in it.
Tony Mensing (08:12):
Sure.
Kapil Arora (08:13):
And you can imagine in your mind, some particles are
by itself, and others areaggregated together.
Tony Mensing (08:20):
Right. There's big spaces and small spaces, and the
reason we care about thosespaces are, like we mentioned
already, air and water are whatoccupy those spaces when we have
a pore space in that soil, andwe need both of those for crop
production,
Kapil Arora (08:37):
Absolutely, Tony.
You're 100% correct that thatpiece itself is what makes
plants grow, because that porespace holds the water. When we
apply fertilizers in the field,the fertilizers go into the soil
particles and get absorbed ifthey are attached with the soil
particles. But when rainhappens, the fertilizer
(09:00):
dissolves into the water, whichis again in those pore spaces.
And the roots are actuallysucking up the water that's
freely available in that porespace, and takes it up. So that
pore space is a very importantthing,
Tony Mensing (09:22):
Sure, and you'll soon get over my head on some of
the plant physiology and some ofthose things, but the big
picture take home from this isthat we need those pore spaces
to be able to supply air andwater for the plants to do What
we're asking them to do, right?
Kapil Arora (09:41):
Yeah, very much so and plants, basically, all the
nutrition they are picking upfrom the soil comes through the
root, through the soil waterthat's in those pore spaces. The
water dissolves the fertilizer,nutrients, whatever other
chemicals and. And the plantsare able to suck it up through
(10:02):
the root system, and that porespace, therefore, is an
important thing for the plantsto grow. But at the same time,
if those pore spaces are pushedtogether and there is
restriction there, it doesimpact the root development as
well, because now the roots haveto work harder to push those
(10:27):
particles apart to make spacefor the root growth itself.
Tony Mensing (10:32):
There's more resistance to them being able to
grow through that soil profile.
Kapil Arora (10:37):
Yes, sure you're absolutely right. So that plays
hand in hand. One, one side isit reduces the pore volume for
the water and nutrients to notbe there. But then at the same
time, the soil becomes resistiveto the root development itself.
One, it's not the plants notbeing able to take up enough
(10:59):
nutrients, but then at the sametime, physically to be able to
grow it, the roots are being metwith resistance, and I'm also,
again, not a crop physiologistby any means. But what I've
learned is the roots, if theyare unable to penetrate through
that resistance, they'll stopgrowing, and they'll go in other
(11:20):
directions, trying to growwherever the resistance is.
Tony Mensing (11:23):
Sure, same thing I do, right path of least
resistance. That's where we wantto go. So I think, kind of, from
a from an overview standpoint,compaction is reducing those
pore spaces. We care about thatbecause we need those pore
spaces for the plants to be ableto do what we're asking them to
do. And then, I guess is thereis it? Is it possible to not
(11:48):
have compaction?
Kapil Arora (11:49):
I don't think it's not possible. I think at given
at any moisture condition, thevertical force from the tractor
and the tractive force when thetractor has an implement
attached with it in ourproduction systems here in the
upper Midwest, and especiallyhere in Iowa, I don't think we
(12:12):
will ever be in a zerocompaction situation, because we
will always have that weight.
The idea would be, can weminimize it?
Tony Mensing (12:24):
We're trying to manage it, right? Yeah, even if
I go for a walk out there, I'mexerting more than my share,
probably, but some force on thatsoil to support myself as I walk
across that right? We're usingequipment that's different than
it was 40 or 50 years ago, andin massive incremental changes,
(12:48):
I think we've gone from smallerto larger from that standpoint.
We're doing some things to stilltry and manage that compaction
problem that we couldpotentially have. Before I lose
sight of this piece, I 100%agree with you. We're not going
to have a point in time where wecan do what we're doing now,
from production ag standpoint,and not have a compactive effort
(13:12):
that's getting applied to thesoil. We can do some things to
manage that. What's one of thebiggest key players in what kind
of detrimental impact we can dofor compaction. So we've had
drastically different years. Thelast couple of years, we had
fairly high level of moisture.
This past year, we've had somefairly dry years. How does that
play into the compactionpicture?
Kapil Arora (13:37):
Yeah, so moisture plays a big role. When equipment
is out in the field, the soilresponds differently, because
it's now somewhat morecompressible. It's somewhat more
I should say, easier to move.
Those particles are easier tomove.
Tony Mensing (13:58):
There's less friction between the particles
with some moisture than whenthey're really dry.
Kapil Arora (14:04):
Dry, so the water kind of acts as a lubricant. And
one way of imagining that wouldbe is if you go up for a walk
out in the lawn or out on thegrass, and if it is wet, if you
walk gently, you'll still seethat you're pushing down with
your feet and your footprintsare there. But now, if you try
(14:28):
to move faster or run across it,you'll actually dig in deeper,
and you leave a deeper footprinton the same space. It's that
point that you brought out,there's less friction, and the
water basically acts as alubricant in those situations.
(14:49):
We have certain amount of workthat needs to be done at
planting and then also atharvest. That workload needs to
get done in a timely fashion,otherwise we are losing degree
days for planting. We can't getthe planting done in time. And
then on the back end, when weare doing harvest, it's the same
(15:10):
situation again. We need to getthe harvest done in a timely
manner. Otherwise you startlosing now crop that's standing
in the field, and you got to getthe money in the bank, so get
the harvest completed, all ofit, and that, that is what
brings the money to the farm. Sowe are forced with having to do
(15:33):
operations at times andsometimes the conditions may not
be the best.
Tony Mensing (15:39):
Yeah, I want to work on the perfect day every
time you need to, but realitydoes not allow for that, right?
Kapil Arora (15:46):
Yes, and even though our farmers here working
in the Upper Midwest are doingtheir best, sometimes they try
to work harder and longer justbecause they don't want to be in
those weather conditions.
Tony Mensing (16:02):
We don't know what is gonna come around the corner
next week, right?
Kapil Arora (16:07):
And I've heard of people putting in 18 hour days
behind the steering wheel justto get get things done in a
timely fashion. And even evenafter our best efforts, our
conditions are not sometimes theideal, and we do end up being in
the field when ideally we maynot want to be.
Tony Mensing (16:29):
Sure. So we have some technologies available to
help mitigate the issue thatwe're discussing here. Right? So
the best thing and correct me ifI'm wrong, but the best thing we
can do to fight compaction is totry and avoid it. Right? That's
easier than trying to fix itafter the fact.
Kapil Arora (16:51):
That is the bottom line. We have had folks here
think about that freeze and thawcycles will pretty much take
away all the compaction. That'snot 100% accurate. It does
depend on how deep thecompaction has gone, and if it
(17:14):
is deep. Now you have to imaginehow the freeze thawing happens.
Tony Mensing (17:21):
We don't get a lot of cyclical action in that
freeze thaw at a deeper depth.
Kapil Arora (17:26):
At a deeper, deeper depth.
Tony Mensing (17:28):
We also would be dependent on moisture, right? So
freeze thaw, where that helpsmitigate, or helps kind of try
to deal with some of thecompaction that we have caused,
we get better results from thatwhen the water in that soil
profile is expanding andbreaking apart those particles,
(17:50):
right? So we have a really drysoil that doesn't have enough
water in it to expand and makethat freeze thaw action help is
that there's a difference inmoisture level and results we
might get from freeze thaw, letalone how many cycles we get
over the winter.
Kapil Arora (18:05):
Yeah, so we can discuss that little bit more in
detail. But to your earlierquestion, minimizing and
avoiding compaction is the bestpossible thing. And I was trying
to say, if you think freeze andthaw is going to help you, that
may not always be the case, andmay not get the benefit out of
it. Now, the reason why we don'tget the benefit out of freeze
(18:27):
and toss cycles is just as wewere talking about deep
compaction, basically, you getdown into 20 plus inches. Then
you are talking about thefreezing during winter has to
freeze that deep to be able tofreeze and create a difference,
there has to be water in thepores, and that water has to
(18:50):
become ice. Because only whenwater becomes ice does its
volume increase, and when thatvolume increases, only then it
actually is able to push thesoil particles apart, or the
aggregates apart. That forcehappens at a microscopic level,
but it's there because ice hasbigger molecules than manure,
(19:13):
and that has to happencyclically, repeatedly and to be
able to get that effect ofcompaction negated. So trying to
get deep compaction to mitigateout with just freeze and thaw
does not really work out in ourfavor, because you can imagine
(19:37):
you need the soil profile fullof water all the way down there,
and then a deep freeze thatfreezes it, and then goes away,
and then comes back again, andthen goes away and then comes
back again. So I think chancesof getting that cyclical freeze
(19:57):
and thaw happening in the. Upper12 inches is a greater
likelihood than getting downinto the two feet and deeper
depths.
Tony Mensing (20:07):
Sure. So it's not that the freeze thaw action
doesn't help with the problemsthat get created. It's more a
matter of that we don't get thatfreeze thaw cyclical action at
that whole soil profile. And aswe've gotten larger equipment,
we probably are trending towardsa deeper compaction level. Am I?
(20:29):
Is that fair to say?
Kapil Arora (20:31):
I would say we have gone down the path of larger
equipment for the reason ofhaving shorter windows at both
planting and harvest to get thework done.
Tony Mensing (20:41):
Right.
Kapil Arora (20:42):
And to be able to get work done quicker. We have
gone to bigger equipment. Nowthe question is, with bigger
equipment, yes, we areincreasing the weight, but our
our footprints, or the load, or,I should say, even pressure on
the soil. How is that beingmanaged on that equipment? If
the footprint is still small andthe tires are still smaller and
(21:07):
the equipment weight hasincreased, now we have increased
the load over the same area onwhich the contact is with the
tires or the tracks, whicheverway you are working.
Tony Mensing (21:21):
We're putting up a higher pressure on that area. So
it's not just dependent on theweight or the size of the
equipment. We also need toaccount for the footprint or the
area that we're spreading thatweight over.
Kapil Arora (21:35):
Yes,
Tony Mensing (21:35):
Sure. Okay, so we want to try to avoid compaction.
We know that that's not going tobe possible every time we can
try to work within what MotherNature gives us, as far as soil
moisture, but knowing that weare up against a production time
clock, that's not always as easyas it sounds, either, what
(22:00):
technologies are available tohelp us with that pressure or
the footprint, or dealing withtrying to minimize, mitigate
what we might be up against withthese larger machines.
Kapil Arora (22:15):
So especially on the tires side, we have what is
being referred as, CTIS, okay.
This is a new technology.
Europeans have been using it forsome time. A]
Tony Mensing (22:31):
And CTIS what?
What does that stand for again?
Kapil Arora (22:34):
It's central tire inflation system, okay, you can
buy this technology and mount iton a tractor. If the tractor
does not have it, or you canmount it on the implement. And
what, what it is basicallysaying is, it's an inflation
system But that implies thatyour tires are deflated. So the
(22:59):
the way this technology worksis, is that once you are in the
field, if you have the rightkind of tires, you can deflate
them, go down to a lower PSIwithin the tire. By deflating
it, you will actually increasethe width of the tire that's in
contact with the soil. You'llalso increase the length,
(23:23):
because now the tires will besitting lower. And essentially
what you have done is that youhave increased your cross
sectional area of contact andthe same load that the tractor
or the tractor plus theimplement was producing is now
(23:44):
spread over a wider area. Ishould say, a larger area, a
larger area, okay, right? Andthat effectively is reducing the
pounds per square inch.
Tony Mensing (23:57):
The pressure of force applied to that soil.
Kapil Arora (24:00):
The pressure applied to that area is now
lower. So by doing that, you arespreading the load on a bigger
area, therefore having lesspounds per square inch or less
pressure. And that helps inkeeping the compaction to lower
(24:20):
than if you were fully inflated,because under fully inflated
conditions, you'll be not aswide, because now the tire will
be sitting straight up and onthe length and the direction of
the travel, the tire will not bein contact with as much soil. So
(24:41):
your total contact area would belower, which, in other words,
means, now the load is spreadover a smaller footprint, and
it's a higher soil pressure.
Tony Mensing (24:56):
Sure. So you you mentioned we need the right kind
of type. Tires for that there's,there are several different
options there. The the big piecewould be a radial type tire of
some sort, rather than a biastype plier. And as far as the
lower inflation pressure goes,again, a big picture view of
(25:16):
this, managing that tirepressure is not something new. I
remember 30 years ago readingthe ag magazines where people
are talking about you need toproperly manage your tire
pressure, right? So one keypoint that you brought up was,
as we get to the field, so tellme a little bit more about why
(25:39):
that's a deciding factor. Why doI not just deflate my tires to
the field level when I'm gettingready to leave home?
Kapil Arora (25:48):
I think you need to be DOD compliant to be out on
the roads. And you also need tomake sure that the friction
factors on the asphalt andpavement are going to be
different. And on gravel, if youare on the gravel, roads are
going to be different than whatyou have out in the field.
Tony Mensing (26:07):
So we're also probably traveling at a road
type speed versus in fieldspeed, right?
Kapil Arora (26:12):
So that's where I was headed, exactly. So with
those different frictionfactors, now your speed factor
is also there, as you justpointed out, out on the road,
you might be in the road gearand going at a faster speed,
miles per hour, or once you arein the field, you may be at
seven or nine miles per hour atthe most. So there's a
(26:35):
difference in the drive speeds,and you need the tires to be
safe and not be any issuescoming up from tire performance
under high speeds out on theroad.
Tony Mensing (26:50):
Sure, we're asking two pretty significantly
different tasks from thosetires, right? So high speed,
high load at transport, is a lotdifferent than a low speed and
maybe even variable load. So ifI think about some implements
have a high draw bar weight attransport, maybe like a front
(27:14):
fold planter, the weight beingtransferred from that implement
to the back axle of a tractormay be a lot different from road
travel to in field, so we mightbe changing not just our speed
but also our loading.
Kapil Arora (27:29):
You're absolutely right. So every implement is
different. The way they areconfigured is different. You
talk about tractor andimplement, now you talk about a
combine. Combine is front heavy,and it's got lot of load up
front, then on the rear tires.
Tony Mensing (27:45):
And it changes a lot.
Kapil Arora (27:47):
And it changes so that that plays a role into it.
So with this CTIS system that isout there in the market now,
there's a couple companies herein central Iowa that I know of
that sell this system that canbe mounted on a on an implement
or a tractor that does not haveit already in it. You can
(28:09):
deflate tires very quickly.
Inflation does take little bitof time, but it's a function of
how big a compressor and how biga compressor cylinder do you
have already mounted with thesystem.
Tony Mensing (28:22):
And how big a tire we're trying to inflate.
Kapil Arora (28:24):
And how big a tire we are trying to inflate, yes.
Combine tires will be differentthan a manure tank tires. So
those, those would bedifferences, definitely. To
consider how big a system do youneed for which implement? Some
of the newer tractors from JohnDeere and Fendt I know of are
(28:46):
already coming. There are, thereare models available that have a
CTIS system alreadypre-installed on them. So you
just have to look for whichmodel that is and and go explore
that out a little bit more.
Tony Mensing (29:01):
Sure, and essentially, we're talking about
the same thing, whether it'ssomething that you would add to
a piece of equipment you alreadyhave, or if it's one of those
two manufacturers or somebodyelse that offers it as a factory
option, or something. We'restill just talking about a way
to be able to onboard of thatmachine inflate and deflate the
(29:25):
tires as we're working, or aswe're switching from road to
field mode, or maybe as we'rechanging our loading from a full
manure slurry tank to an emptymanure slurry tank.
Kapil Arora (29:41):
Yeah, all of those conditions apply. And then once
you are done in the field, andyou're coming back out on the
road again, if you're haulingthat equipment, piece of
equipment, or if you're justtracting a empty manure tank,
again, you got to get roadworthy and be able to handle the
forces under higher drivespeeds. Yeah, so those, those
(30:02):
things come into play rightaway.
Tony Mensing (30:04):
And how do I know where I should be at for an
inflation pressure? Somethingthat I think about in this space
is, do people truly know whattheir axle load is on those
pieces of equipment? And then,if we do, how do we know where
we should be looking to be? Asfar as inflation pressure,
there's probably severaldifferent things that may affect
(30:27):
that tire construction, so tiremanufacturer recommendations and
lots of other pieces. Give meyour take on that, Kapil.
Kapil Arora (30:34):
So you may have already answered that question
earlier, but it's good to ask itin this fashion. I think you
mentioned looking up equipmentcatalogs and looking up the
online when these days you haveinformation available online
from different manufacturers aswell. So you can look up on the
(30:56):
tires itself as to what are theinflation pressures for
different drive speeds andloadings, okay? I think that's
what you were asking.
Tony Mensing (31:09):
Yeah, and when we're thinking about compaction,
loading and those type ofthings, duals are something that
come to mind a lot of times. Soyou'll see, if you look in those
tables, I believe that justbecause we double the amount of
tires does not mean that we getto half the inflation pressure
or that it doubles the loadingcapacity, right? So there's,
(31:33):
there's some give and take forhaving four tires on the same
axle versus two tires we don'tit's not necessarily just a
linear relationship of how muchmore load those can absorb.
Kapil Arora (31:47):
Putting two more track tire tractors on the same
axle also increases the weighton those axles. So yeah, you're
absolutely right. It's not alinear relationship that you can
just now have twice as much loadbecause now you have four, four
tires on the same axle. So youdo need to look up for those
(32:07):
tires specifically, as youmentioned, are they radial ply
or bias ply? And if they areradial ply, what are their
ratings and what is the minimuminflation pressure they can be
deflated down to to be able todo the work that that you are
looking for. You don't want toover deflate them and get down
(32:29):
to real low pressures, becausethen you will hurt the tire, and
you can actually create a biggerproblem that your tire is now
damaged and then you don't wantto go down that path. So So you
absolutely do need to know whatyour operating limits are before
you actually go into this domainof inflating deflating. This is
(32:52):
not just telling your hired helpto go deflate the tire. It needs
to be very clear and veryprecise as to we are going to go
down to 10 PSI or 12 PSI on thetire pressure, not any lower.
Tony Mensing (33:08):
Right, and that specific to what machine, what
application, what loading thatyour whatever value that's going
to be. But a visual assessmentof what that tire looks like is
not a good way to decide whatyou should do, right? We need to
know probably what load weactually are going to have,
which, I'm not sure that wealways have a good handle on
(33:29):
that, but load and then tirespecific, what our limits are
for where we can work in thatrange. And some of the tire
manufacturers have someproprietary tire technologies
that that are their own specificand then there are some
categories that are tirescategorized in these bunches
(33:50):
across multiple manufacturers.
So really, it's not somethingthat you nor I could sit here
and say, well, for a grain cartwith this size tire, it should
be at x amount of inflation whenit's fully loaded.
Kapil Arora (34:04):
You're very right, Tony, and that's the piece you
have explained better than whatI was explaining it as. So
understand what you're trying todo, understand the loading
you're going to be loading thatequipment to or, if it is a
grain cart, how fully going tomake it and understand all that
before you actually decide to doany deflation.
Tony Mensing (34:27):
And the safe answer, what I feel like I have
seen maybe out in thecountryside, is people over
inflate because we don't want tohave the problems that you can
have from the under inflation.
So it feels like maybe the ifpeople are going to error one
side or the other, we visuallyassess and are probably more
times than not, overinflated,and especially if we're not
(34:49):
changing those tire pressuresfrom road transport to infield,
if we're decreasing that speedor decreasing that load, we want
to be able to, as you said,travel safely down the road. So
if we're picking one or theother, we're probably not,
either not right at one or notright at both, and generally,
probably set up to be higherpressure than needed for that
(35:13):
field work.
Kapil Arora (35:16):
Definitely, there's a learning curve here, and we do
need to make sure that we startout small. We gain experience
with one system, understand thelimitations of the system and
how it works and what whatpoints we need to stop at in
that operation, because now theoperation has to have a few
(35:40):
pauses in between to deflate,and then back inflate, and then,
if need, deflate again. And thenand get a good understanding of
that and get a good sense ofcomfort in doing it, before you
decide that you're going to putthis on every piece of
(36:00):
equipment. I would, I wouldcaution, because you need to
have that experience, and youneed to learn about it. So one,
we stay safe on the road. Andtwo, when we are in the field,
we are not damaging those tires,because we still want our tires
to work, and radial tires arenot cheap
Tony Mensing (36:22):
We want to make the most of our investment there
too, right?
Kapil Arora (36:25):
Yes, absolutely, yes.
Tony Mensing (36:26):
And I guess kind of to go along with that there
are probably for everyoperation, some some specific
applications that may be ahigher impact to look at being
able to have a more significantimpact trying to mitigate that
compaction, right? So like Isaid, one that comes to my mind
(36:49):
is, particularly in the fall, wehave high loading from grain
carts or moving the crop off thefield. And then in the spring,
like I mentioned, those centerfor front fold planters, some
applications where we have areally large disparity from what
we're asking of those tires,from the road transport mode to
the field mode. So might be ableto pick out a couple operations
(37:13):
that are able to they might havea bigger piece of the pie as far
as the compaction damage that wemight be doing.
Kapil Arora (37:20):
Yeah. So definitely, where we have,
especially those things, wherewe have higher loading or higher
pressure on the soil, thosewould be the biggest impact, if
we are able to reduce thepressure on those. Again, we
were talking about this earlierfreeze. Thaw doesn't help with
deep compaction, and thosebigger pieces of equipment may
(37:42):
very well be the ones creatingdeep compaction. So if we can
help and minimize and keepcompaction shallower, freeze
thaw will help. Many people haveseen benefit from tillage as
well. You could do tillage, buttillage points only go so deep.
(38:03):
If you try to go deeper, thenyou yourself need more tractive
force for that tractor to beable to.
Tony Mensing (38:10):
It can be a double edged sword, right, and you can
actually do some compactive harmif we're operating in conditions
that aren't conducive to breakup those soil particles if we
don't have the right moisturelevel, we could actually be
doing more damage than we'redoing good.
Kapil Arora (38:28):
And then I've heard folks use cover crops as well to
help with some of thecompaction, all of these
practices are there to helpmitigate what compaction that
would have happened. But again,if we can keep compaction
shallower, and this technologyof CTIS definitely looks like
(38:49):
the one that can help.
Tony Mensing (38:51):
It makes it possible to do what we've known
for years we should do, which ismanage our tire pressure, right?
So it's it's another tool thatallows us to do the things that
people like you have beentelling folks they need to pay
attention to for a long time. Itjust hasn't been nearly as
convenient as it might be withsome of these systems to make
that happen in the past.
Kapil Arora (39:12):
Right. And previously, not having a mounted
system and having air availableat the shop created an issue,
because now, if you are farminga field that's two miles down
the road and you don't have ashop there, you just have a
field there, or you're justrenting it, it created a
logistics issue of, how do Imanage my tire pressure, and how
(39:33):
do I do this? And then when Iget done, then somebody has to
bring a compressor on a truck,pickup truck, and wait there and
do it. And basically, folks havetaken that system that was fixed
in the shop or was on a pickuptruck and mounted it directly
onto the tractor or theimplement and given us the
(39:57):
controls in the cab to be ableto push buttons from. On the cab
itself and be able to do it.
Tony Mensing (40:02):
Sure, and you're doing the inflation and
deflation on the go, basically,right? So not only do you have
the system on the machineitself, but it's not like we
have to stop necessarily and getout to make that system work. We
can be traveling as it's doingits job to you, as long as we're
cognizant of making sure that weallow it enough time to get to
(40:26):
the point that we need it to beto operate. Right?
Kapil Arora (40:29):
Yes, if you are careful and have accounted for
all the variables, you could doit on the go, and
Tony Mensing (40:36):
that'd be something maybe to discuss with
the equipment supplier that youwould look at for one of these
CTIS systems.
Kapil Arora (40:44):
But definitely I'm not the expert on CTIS system. I
do know how the system works andoperates, and yes, you should
discuss all those options withthe provider, with the
manufacturer of the CTIS systemas to what's the best way to
operate them if you are notwanting to stop or pause at all?
Tony Mensing (41:07):
Sure, and there's lots of questions to learn
answers to, hopefully, at somepoint, the deep compaction is
something that I think maybe wehave some more questions than we
maybe even have answers on rightnow, for people that want to
have one of these type ofsystems, or look at this as an
option to help them mitigatecompaction, lots of tire
(41:28):
options, multiple CTISsuppliers, lots of different
pieces. But I guess where I kindof come back to is it's not
necessarily new for people toknow how important tire
inflation pressure is, butagain, this allows you to be
able to manage that a lot betterthan we've been able to in the
(41:48):
past, to physically be able tomanage it, versus having to pick
a compromise somewhere between Ireally want to be here for my
field work and I need to be herefor my road transport or
whatever the whatever thebookends are on that we can work
for the situation that we haveat hand instead of trying to
compromise between two or threedifferent levels.
Kapil Arora (42:11):
Yeah, and I think as you mentioned, tire companies
have been publishing those datafor however they do their tire
testing, and they understandfrom their manufacturing what
kind of loads those track tirescan handle. So the data is
available from the tiremanufacturers, and if you're
(42:33):
buying it through a dealer, youcan very easily request that
information, and they canprovide you with with the
tables, and you should be ableto go off of those tables,
Tony Mensing (42:45):
Sure, yeah. Well, tons of more in depth
conversation that I think thatwe could have, or even bring in
some other folks to discussfurther on this topic that tire
technologies themselves. Lots tomaybe know and understand about
compaction that we don'tnecessarily even know today.
Some of the other potentialmitigation practices, cover
(43:07):
crops, like you mentioned, thereare lots of questions and some
answers, but some morediscussion that we could have on
that. But I think, I think fortoday, you've done a really
great job of covering kind ofthe basic overview of what
compaction is, why we need tocare about it, some potential
ways to mitigate it, knowingthat we're not going to be able
(43:28):
to eliminate compactionwholesale. And I guess I would
welcome a last comment or two,and then I think we'll probably
wrap up for today save
Kapil Arora (43:39):
for another episode. I think if we invent
implements that are operated byhelicopters so we have no soil
contact, maybe that will be asituation where, where we may
not have any compaction, or verywell, even in that you still
have the implement on theground.
Tony Mensing (44:01):
as long as we have some kind of equipment soil
interaction, we probably havepotential for compaction.
Kapil Arora (44:07):
I would agree with that.
Tony Mensing (44:08):
Yeah, well, thanks again for for participating on
the podcast with me today,Kapil, and again, I'm Tony
Mensing field agriculturalengineer with Iowa State
University Extension andOutreach. And to the listeners,
thanks for tuning in to thisepisode, and if you have follow
up questions or comments, feelfree to reach out to anyone on
the ISU Extension Outreach agengineering team for some
(44:31):
further discussion or furtherinsight on compaction. You can
search the Iowa State UniversityExtension and Outreach store for
publication 3180, which isUnderstanding and Managing Soil
Compaction, and hope to have youback on another episode of
Engineering Your Farm at a laterdate. Thank you.
This institution is an equalopportunity provider. For the
(44:54):
full non discriminationstatement or accommodation
inquiries, go towww.extension.iastate.edu/legal.
Hello, and welcome to the Engineering Your Farm
podcast. This podcast isproduced by the Iowa State
University Extension andOutreach field agricultural
engineering team. Welcome backto another episode of the
EngineeringYour Farm podcast.
I'm Tony Mensing, agriculturalengineer with Iowa State
University Extension andOutreach in southwest Iowa, and
today I'm very happy to have Dr.
(00:37):
Kapil Arora, a colleague ofmine, also an agricultural
engineer with Iowa StateUniversity Extension and
Outreach as my guest on theshow. Welcome Kapil, thanks for
being here today.
Kapil Arora (00:47):
Hey Tony, thanks for having me on here today.
Tony Mensing (00:50):
Yeah, absolutely.
If you want to go ahead and givea little more introduction of
your background for thelisteners, that'd be great.
Kapil Arora (00:57):
Yeah, Tony, I've been in extension now for 23
years, I've been serving in therole of the extension engineer
for Central Iowa for all theseyears, and have been covering
about 17 to 20 counties incentral Iowa. And as you know,
we are short few staff. Sotypically that count is higher.
(01:21):
Have been involved in farmlanddrainage, composting, manure
management, and today we arehere to talk about soil
compaction, which happens to bean integral part of all farm
machinery, whether you'redealing with manure issues or
you're dealing with planting andtillage and and all those
(01:43):
things. I do want to point outthat our research lead for soil
compaction is actually Dr.
Mehari Tekeste. He is associateprofessor in agricultural
engineering here, and he's alsothe director for soil machine
dynamics lab here at Iowa StateUniversity. He does work with
(02:06):
different tracks and tires andtesting in his lab, and has
been, has been producing somework on that part.
Tony Mensing (02:19):
Sure. So you have a varied background, as you
described a little bit, but havesome resource knowledge base in
the compaction arena, and Dr.
Tekeste is the lead in that labspace. But we'll have a little
kind of an overview discussiontoday, and hopefully maybe
follow up in some later episodeswith some more in depth in some
of these topic areas that we getdialed in on a little bit today.
(02:42):
So
Kapil Arora (02:44):
Yeah, and that'll be more up the alley for Dr
Tekeste to answer some of thosein depth, detailed scientific
questions. As as you said, youare also in a similar role as
me. So we are more rounded, moremore broad based.
Tony Mensing (03:02):
Sure, yeah, we get to do a little bit of a lot of
different things, and there arecertainly folks that are more
able to dedicate their time to aparticular area. So yeah, we'll
kind of cover some generalthings on compaction today, and
like I said, hopefully follow upin a later episode with some
more detailed pieces down, adown a rabbit hole, maybe, so to
(03:22):
speak, in another area or two,but maybe just kick off today. I
think a lot of people probablyhave a basic understanding, but
physically, what is happening?
What's happening when we have acompaction issue? What happened
in the soil profile?
Kapil Arora (03:36):
Right? So in very simple terms, compaction is soil
particles getting pushedtogether.
Tony Mensing (03:45):
Okay.
Kapil Arora (03:46):
In a uncompacted soil, there is space in between
these particles and aggregates,and we call it the pore space.
This pore space helps to holdwater in it, and also aerates
the soil and also allows theroots to develop through it. But
when you have heavy equipmentgoing over it under unfavorable
(04:11):
conditions, we have morepressure on the soil, and can
come from even lighter equipmentif they are not appropriately
configured. In that case, thatload, or the pressure on the
soil that's exerted downwardsactually pushes the soil
particles together.
Tony Mensing (04:31):
Sure.
Kapil Arora (04:32):
And if the piece of equipment, let's say it's a
tractor, and it's pulling animplement behind it, that
traction force that's needed bythe tractor increases because
it's now also having to havepower for the implement to be
able to do the work. Let's sayit's a vertical till tool
(04:56):
toolbar, or we are just pullinga planter behind the tractor. In
both cases, there are pointsthat are in contact with the
soil, and they are going to needsome draw bar power, which the
tractor has to be able toprovide, but the tractor is
bringing that into play with thetraction it's getting from the
(05:17):
soil surface itself. So as thatforce gets applied on the soil,
that pressure basically pushesthe particles together.
Tony Mensing (05:27):
Sure. So maybe let me recap, and you point out if I
missed something in here, butsoil profile as we think about
it in in this part of the worldwhere we're trying to talk
through production ag growingcrops in Iowa. Here, soil
profile is primarily made up ofthe soil particles themselves,
and then air and water. And theair and water are in that pore
(05:52):
space, as you described, right?
So if we compact that soil,we're reducing the amount of
that pore space that's availableto hold the air in water.
Kapil Arora (06:02):
Very much so. And one way to look at it would be,
if you were to take a corethat's one foot deep and put it
in a let's say we take out arectangular box, so as we see
what that profile is, it's onefoot wide by one foot long, and
then one foot deep, and we canput it in a Plexiglas.
Tony Mensing (06:25):
Sure. We're looking at basically one cubic
foot.
Kapil Arora (06:28):
One cubic foot of the soil, but we are able to put
it in a clear plastic probecontainer, so we can see it on
the side.
Tony Mensing (06:37):
Sure.
Kapil Arora (06:37):
And you can put water on it, and you'll see the
soil is able to hold it. It'sholding that water in the pore
space.
Tony Mensing (06:44):
Right.
Kapil Arora (06:45):
Now, once you bring equipment over it and exert
forces on it, you'll see thesame space getting pushed down.
And now that one cubic foot ofsoil, even though we started out
with one cubic foot, you'll seeit has compressed down on the
top surface.
Tony Mensing (07:04):
Sure.
Kapil Arora (07:05):
It's not the same height, even though it's the
same width and length.
Tony Mensing (07:10):
Sure.
Kapil Arora (07:10):
But it's not the same height. Now the volume has
reduced. Well, physically, wehaven't taken any soil out of
that one cubic foot box.
Tony Mensing (07:21):
Right.
Kapil Arora (07:21):
So it's that pore space that actually is reduced
because soil is giving under theweight it's getting subjected
to.
Tony Mensing (07:30):
Sure, it doesn't have the ability to withstand
that force that's holding theequipment up vertically. Plus,
as you were trying to point outthere the tractors or the
machines themselves, have toapply that tractive effort, that
tractive force, to be able topull the implement behind. So
not only is it supporting theload vertically, it's also
(07:51):
supporting that tractive load.
So we're basically compressing,squeezing that soil to be able
to get that equal and oppositereaction, to be able to pull the
implement plus hold it upright.
Kapil Arora (08:03):
Yeah, very much so.
And that's what that wholeprofile is. It's built of sand,
silt and clay particles, butit's got pore space in it.
Tony Mensing (08:12):
Sure.
Kapil Arora (08:13):
And you can imagine in your mind, some particles are
by itself, and others areaggregated together.
Tony Mensing (08:20):
Right. There's big spaces and small spaces, and the
reason we care about thosespaces are, like we mentioned
already, air and water are whatoccupy those spaces when we have
a pore space in that soil, andwe need both of those for crop
production,
Kapil Arora (08:37):
Absolutely, Tony.
You're 100% correct that thatpiece itself is what makes
plants grow, because that porespace holds the water. When we
apply fertilizers in the field,the fertilizers go into the soil
particles and get absorbed ifthey are attached with the soil
particles. But when rainhappens, the fertilizer
(09:00):
dissolves into the water, whichis again in those pore spaces.
And the roots are actuallysucking up the water that's
freely available in that porespace, and takes it up. So that
pore space is a very importantthing,
Tony Mensing (09:22):
Sure, and you'll soon get over my head on some of
the plant physiology and some ofthose things, but the big
picture take home from this isthat we need those pore spaces
to be able to supply air andwater for the plants to do What
we're asking them to do, right?
Kapil Arora (09:41):
Yeah, very much so and plants, basically, all the
nutrition they are picking upfrom the soil comes through the
root, through the soil waterthat's in those pore spaces. The
water dissolves the fertilizer,nutrients, whatever other
chemicals and. And the plantsare able to suck it up through
(10:02):
the root system, and that porespace, therefore, is an
important thing for the plantsto grow. But at the same time,
if those pore spaces are pushedtogether and there is
restriction there, it doesimpact the root development as
well, because now the roots haveto work harder to push those
(10:27):
particles apart to make spacefor the root growth itself.
Tony Mensing (10:32):
There's more resistance to them being able to
grow through that soil profile.
Kapil Arora (10:37):
Yes, sure you're absolutely right. So that plays
hand in hand. One, one side isit reduces the pore volume for
the water and nutrients to notbe there. But then at the same
time, the soil becomes resistiveto the root development itself.
One, it's not the plants notbeing able to take up enough
(10:59):
nutrients, but then at the sametime, physically to be able to
grow it, the roots are being metwith resistance, and I'm also,
again, not a crop physiologistby any means. But what I've
learned is the roots, if theyare unable to penetrate through
that resistance, they'll stopgrowing, and they'll go in other
(11:20):
directions, trying to growwherever the resistance is.
Tony Mensing (11:23):
Sure, same thing I do, right path of least
resistance. That's where we wantto go. So I think, kind of, from
a from an overview standpoint,compaction is reducing those
pore spaces. We care about thatbecause we need those pore
spaces for the plants to be ableto do what we're asking them to
do. And then, I guess is thereis it? Is it possible to not
(11:48):
have compaction?
Kapil Arora (11:49):
I don't think it's not possible. I think at given
at any moisture condition, thevertical force from the tractor
and the tractive force when thetractor has an implement
attached with it in ourproduction systems here in the
upper Midwest, and especiallyhere in Iowa, I don't think we
(12:12):
will ever be in a zerocompaction situation, because we
will always have that weight.
The idea would be, can weminimize it?
Tony Mensing (12:24):
We're trying to manage it, right? Yeah, even if
I go for a walk out there, I'mexerting more than my share,
probably, but some force on thatsoil to support myself as I walk
across that right? We're usingequipment that's different than
it was 40 or 50 years ago, andin massive incremental changes,
(12:48):
I think we've gone from smallerto larger from that standpoint.
We're doing some things to stilltry and manage that compaction
problem that we couldpotentially have. Before I lose
sight of this piece, I 100%agree with you. We're not going
to have a point in time where wecan do what we're doing now,
from production ag standpoint,and not have a compactive effort
(13:12):
that's getting applied to thesoil. We can do some things to
manage that. What's one of thebiggest key players in what kind
of detrimental impact we can dofor compaction. So we've had
drastically different years. Thelast couple of years, we had
fairly high level of moisture.
This past year, we've had somefairly dry years. How does that
play into the compactionpicture?
Kapil Arora (13:37):
Yeah, so moisture plays a big role. When equipment
is out in the field, the soilresponds differently, because
it's now somewhat morecompressible. It's somewhat more
I should say, easier to move.
Those particles are easier tomove.
Tony Mensing (13:58):
There's less friction between the particles
with some moisture than whenthey're really dry.
Kapil Arora (14:04):
Dry, so the water kind of acts as a lubricant. And
one way of imagining that wouldbe is if you go up for a walk
out in the lawn or out on thegrass, and if it is wet, if you
walk gently, you'll still seethat you're pushing down with
your feet and your footprintsare there. But now, if you try
(14:28):
to move faster or run across it,you'll actually dig in deeper,
and you leave a deeper footprinton the same space. It's that
point that you brought out,there's less friction, and the
water basically acts as alubricant in those situations.
(14:49):
We have certain amount of workthat needs to be done at
planting and then also atharvest. That workload needs to
get done in a timely fashion,otherwise we are losing degree
days for planting. We can't getthe planting done in time. And
then on the back end, when weare doing harvest, it's the same
(15:10):
situation again. We need to getthe harvest done in a timely
manner. Otherwise you startlosing now crop that's standing
in the field, and you got to getthe money in the bank, so get
the harvest completed, all ofit, and that, that is what
brings the money to the farm. Sowe are forced with having to do
(15:33):
operations at times andsometimes the conditions may not
be the best.
Tony Mensing (15:39):
Yeah, I want to work on the perfect day every
time you need to, but realitydoes not allow for that, right?
Kapil Arora (15:46):
Yes, and even though our farmers here working
in the Upper Midwest are doingtheir best, sometimes they try
to work harder and longer justbecause they don't want to be in
those weather conditions.
Tony Mensing (16:02):
We don't know what is gonna come around the corner
next week, right?
Kapil Arora (16:07):
And I've heard of people putting in 18 hour days
behind the steering wheel justto get get things done in a
timely fashion. And even evenafter our best efforts, our
conditions are not sometimes theideal, and we do end up being in
the field when ideally we maynot want to be.
Tony Mensing (16:29):
Sure. So we have some technologies available to
help mitigate the issue thatwe're discussing here. Right? So
the best thing and correct me ifI'm wrong, but the best thing we
can do to fight compaction is totry and avoid it. Right? That's
easier than trying to fix itafter the fact.
Kapil Arora (16:51):
That is the bottom line. We have had folks here
think about that freeze and thawcycles will pretty much take
away all the compaction. That'snot 100% accurate. It does
depend on how deep thecompaction has gone, and if it
(17:14):
is deep. Now you have to imaginehow the freeze thawing happens.
Tony Mensing (17:21):
We don't get a lot of cyclical action in that
freeze thaw at a deeper depth.
Kapil Arora (17:26):
At a deeper, deeper depth.
Tony Mensing (17:28):
We also would be dependent on moisture, right? So
freeze thaw, where that helpsmitigate, or helps kind of try
to deal with some of thecompaction that we have caused,
we get better results from thatwhen the water in that soil
profile is expanding andbreaking apart those particles,
(17:50):
right? So we have a really drysoil that doesn't have enough
water in it to expand and makethat freeze thaw action help is
that there's a difference inmoisture level and results we
might get from freeze thaw, letalone how many cycles we get
over the winter.
Kapil Arora (18:05):
Yeah, so we can discuss that little bit more in
detail. But to your earlierquestion, minimizing and
avoiding compaction is the bestpossible thing. And I was trying
to say, if you think freeze andthaw is going to help you, that
may not always be the case, andmay not get the benefit out of
it. Now, the reason why we don'tget the benefit out of freeze
(18:27):
and toss cycles is just as wewere talking about deep
compaction, basically, you getdown into 20 plus inches. Then
you are talking about thefreezing during winter has to
freeze that deep to be able tofreeze and create a difference,
there has to be water in thepores, and that water has to
(18:50):
become ice. Because only whenwater becomes ice does its
volume increase, and when thatvolume increases, only then it
actually is able to push thesoil particles apart, or the
aggregates apart. That forcehappens at a microscopic level,
but it's there because ice hasbigger molecules than manure,
(19:13):
and that has to happencyclically, repeatedly and to be
able to get that effect ofcompaction negated. So trying to
get deep compaction to mitigateout with just freeze and thaw
does not really work out in ourfavor, because you can imagine
(19:37):
you need the soil profile fullof water all the way down there,
and then a deep freeze thatfreezes it, and then goes away,
and then comes back again, andthen goes away and then comes
back again. So I think chancesof getting that cyclical freeze
(19:57):
and thaw happening in the. Upper12 inches is a greater
likelihood than getting downinto the two feet and deeper
depths.
Tony Mensing (20:07):
Sure. So it's not that the freeze thaw action
doesn't help with the problemsthat get created. It's more a
matter of that we don't get thatfreeze thaw cyclical action at
that whole soil profile. And aswe've gotten larger equipment,
we probably are trending towardsa deeper compaction level. Am I?
(20:29):
Is that fair to say?
Kapil Arora (20:31):
I would say we have gone down the path of larger
equipment for the reason ofhaving shorter windows at both
planting and harvest to get thework done.
Tony Mensing (20:41):
Right.
Kapil Arora (20:42):
And to be able to get work done quicker. We have
gone to bigger equipment. Nowthe question is, with bigger
equipment, yes, we areincreasing the weight, but our
our footprints, or the load, or,I should say, even pressure on
the soil. How is that beingmanaged on that equipment? If
the footprint is still small andthe tires are still smaller and
(21:07):
the equipment weight hasincreased, now we have increased
the load over the same area onwhich the contact is with the
tires or the tracks, whicheverway you are working.
Tony Mensing (21:21):
We're putting up a higher pressure on that area. So
it's not just dependent on theweight or the size of the
equipment. We also need toaccount for the footprint or the
area that we're spreading thatweight over.
Kapil Arora (21:35):
Yes,
Tony Mensing (21:35):
Sure. Okay, so we want to try to avoid compaction.
We know that that's not going tobe possible every time we can
try to work within what MotherNature gives us, as far as soil
moisture, but knowing that weare up against a production time
clock, that's not always as easyas it sounds, either, what
(22:00):
technologies are available tohelp us with that pressure or
the footprint, or dealing withtrying to minimize, mitigate
what we might be up against withthese larger machines.
Kapil Arora (22:15):
So especially on the tires side, we have what is
being referred as, CTIS, okay.
This is a new technology.
Europeans have been using it forsome time. A]
Tony Mensing (22:31):
And CTIS what?
What does that stand for again?
Kapil Arora (22:34):
It's central tire inflation system, okay, you can
buy this technology and mount iton a tractor. If the tractor
does not have it, or you canmount it on the implement. And
what, what it is basicallysaying is, it's an inflation
system But that implies thatyour tires are deflated. So the
(22:59):
the way this technology worksis, is that once you are in the
field, if you have the rightkind of tires, you can deflate
them, go down to a lower PSIwithin the tire. By deflating
it, you will actually increasethe width of the tire that's in
contact with the soil. You'llalso increase the length,
(23:23):
because now the tires will besitting lower. And essentially
what you have done is that youhave increased your cross
sectional area of contact andthe same load that the tractor
or the tractor plus theimplement was producing is now
(23:44):
spread over a wider area. Ishould say, a larger area, a
larger area, okay, right? Andthat effectively is reducing the
pounds per square inch.
Tony Mensing (23:57):
The pressure of force applied to that soil.
Kapil Arora (24:00):
The pressure applied to that area is now
lower. So by doing that, you arespreading the load on a bigger
area, therefore having lesspounds per square inch or less
pressure. And that helps inkeeping the compaction to lower
(24:20):
than if you were fully inflated,because under fully inflated
conditions, you'll be not aswide, because now the tire will
be sitting straight up and onthe length and the direction of
the travel, the tire will not bein contact with as much soil. So
(24:41):
your total contact area would belower, which, in other words,
means, now the load is spreadover a smaller footprint, and
it's a higher soil pressure.
Tony Mensing (24:56):
Sure. So you you mentioned we need the right kind
of type. Tires for that there's,there are several different
options there. The the big piecewould be a radial type tire of
some sort, rather than a biastype plier. And as far as the
lower inflation pressure goes,again, a big picture view of
(25:16):
this, managing that tirepressure is not something new. I
remember 30 years ago readingthe ag magazines where people
are talking about you need toproperly manage your tire
pressure, right? So one keypoint that you brought up was,
as we get to the field, so tellme a little bit more about why
(25:39):
that's a deciding factor. Why doI not just deflate my tires to
the field level when I'm gettingready to leave home?
Kapil Arora (25:48):
I think you need to be DOD compliant to be out on
the roads. And you also need tomake sure that the friction
factors on the asphalt andpavement are going to be
different. And on gravel, if youare on the gravel, roads are
going to be different than whatyou have out in the field.
Tony Mensing (26:07):
So we're also probably traveling at a road
type speed versus in fieldspeed, right?
Kapil Arora (26:12):
So that's where I was headed, exactly. So with
those different frictionfactors, now your speed factor
is also there, as you justpointed out, out on the road,
you might be in the road gearand going at a faster speed,
miles per hour, or once you arein the field, you may be at
seven or nine miles per hour atthe most. So there's a
(26:35):
difference in the drive speeds,and you need the tires to be
safe and not be any issuescoming up from tire performance
under high speeds out on theroad.
Tony Mensing (26:50):
Sure, we're asking two pretty significantly
different tasks from thosetires, right? So high speed,
high load at transport, is a lotdifferent than a low speed and
maybe even variable load. So ifI think about some implements
have a high draw bar weight attransport, maybe like a front
(27:14):
fold planter, the weight beingtransferred from that implement
to the back axle of a tractormay be a lot different from road
travel to in field, so we mightbe changing not just our speed
but also our loading.
Kapil Arora (27:29):
You're absolutely right. So every implement is
different. The way they areconfigured is different. You
talk about tractor andimplement, now you talk about a
combine. Combine is front heavy,and it's got lot of load up
front, then on the rear tires.
Tony Mensing (27:45):
And it changes a lot.
Kapil Arora (27:47):
And it changes so that that plays a role into it.
So with this CTIS system that isout there in the market now,
there's a couple companies herein central Iowa that I know of
that sell this system that canbe mounted on a on an implement
or a tractor that does not haveit already in it. You can
(28:09):
deflate tires very quickly.
Inflation does take little bitof time, but it's a function of
how big a compressor and how biga compressor cylinder do you
have already mounted with thesystem.
Tony Mensing (28:22):
And how big a tire we're trying to inflate.
Kapil Arora (28:24):
And how big a tire we are trying to inflate, yes.
Combine tires will be differentthan a manure tank tires. So
those, those would bedifferences, definitely. To
consider how big a system do youneed for which implement? Some
of the newer tractors from JohnDeere and Fendt I know of are
(28:46):
already coming. There are, thereare models available that have a
CTIS system alreadypre-installed on them. So you
just have to look for whichmodel that is and and go explore
that out a little bit more.
Tony Mensing (29:01):
Sure, and essentially, we're talking about
the same thing, whether it'ssomething that you would add to
a piece of equipment you alreadyhave, or if it's one of those
two manufacturers or somebodyelse that offers it as a factory
option, or something. We'restill just talking about a way
to be able to onboard of thatmachine inflate and deflate the
(29:25):
tires as we're working, or aswe're switching from road to
field mode, or maybe as we'rechanging our loading from a full
manure slurry tank to an emptymanure slurry tank.
Kapil Arora (29:41):
Yeah, all of those conditions apply. And then once
you are done in the field, andyou're coming back out on the
road again, if you're haulingthat equipment, piece of
equipment, or if you're justtracting a empty manure tank,
again, you got to get roadworthy and be able to handle the
forces under higher drivespeeds. Yeah, so those, those
(30:02):
things come into play rightaway.
Tony Mensing (30:04):
And how do I know where I should be at for an
inflation pressure? Somethingthat I think about in this space
is, do people truly know whattheir axle load is on those
pieces of equipment? And then,if we do, how do we know where
we should be looking to be? Asfar as inflation pressure,
there's probably severaldifferent things that may affect
(30:27):
that tire construction, so tiremanufacturer recommendations and
lots of other pieces. Give meyour take on that, Kapil.
Kapil Arora (30:34):
So you may have already answered that question
earlier, but it's good to ask itin this fashion. I think you
mentioned looking up equipmentcatalogs and looking up the
online when these days you haveinformation available online
from different manufacturers aswell. So you can look up on the
(30:56):
tires itself as to what are theinflation pressures for
different drive speeds andloadings, okay? I think that's
what you were asking.
Tony Mensing (31:09):
Yeah, and when we're thinking about compaction,
loading and those type ofthings, duals are something that
come to mind a lot of times. Soyou'll see, if you look in those
tables, I believe that justbecause we double the amount of
tires does not mean that we getto half the inflation pressure
or that it doubles the loadingcapacity, right? So there's,
(31:33):
there's some give and take forhaving four tires on the same
axle versus two tires we don'tit's not necessarily just a
linear relationship of how muchmore load those can absorb.
Kapil Arora (31:47):
Putting two more track tire tractors on the same
axle also increases the weighton those axles. So yeah, you're
absolutely right. It's not alinear relationship that you can
just now have twice as much loadbecause now you have four, four
tires on the same axle. So youdo need to look up for those
(32:07):
tires specifically, as youmentioned, are they radial ply
or bias ply? And if they areradial ply, what are their
ratings and what is the minimuminflation pressure they can be
deflated down to to be able todo the work that that you are
looking for. You don't want toover deflate them and get down
(32:29):
to real low pressures, becausethen you will hurt the tire, and
you can actually create a biggerproblem that your tire is now
damaged and then you don't wantto go down that path. So So you
absolutely do need to know whatyour operating limits are before
you actually go into this domainof inflating deflating. This is
(32:52):
not just telling your hired helpto go deflate the tire. It needs
to be very clear and veryprecise as to we are going to go
down to 10 PSI or 12 PSI on thetire pressure, not any lower.
Tony Mensing (33:08):
Right, and that specific to what machine, what
application, what loading thatyour whatever value that's going
to be. But a visual assessmentof what that tire looks like is
not a good way to decide whatyou should do, right? We need to
know probably what load weactually are going to have,
which, I'm not sure that wealways have a good handle on
(33:29):
that, but load and then tirespecific, what our limits are
for where we can work in thatrange. And some of the tire
manufacturers have someproprietary tire technologies
that that are their own specificand then there are some
categories that are tirescategorized in these bunches
(33:50):
across multiple manufacturers.
So really, it's not somethingthat you nor I could sit here
and say, well, for a grain cartwith this size tire, it should
be at x amount of inflation whenit's fully loaded.
Kapil Arora (34:04):
You're very right, Tony, and that's the piece you
have explained better than whatI was explaining it as. So
understand what you're trying todo, understand the loading
you're going to be loading thatequipment to or, if it is a
grain cart, how fully going tomake it and understand all that
before you actually decide to doany deflation.
Tony Mensing (34:27):
And the safe answer, what I feel like I have
seen maybe out in thecountryside, is people over
inflate because we don't want tohave the problems that you can
have from the under inflation.
So it feels like maybe the ifpeople are going to error one
side or the other, we visuallyassess and are probably more
times than not, overinflated,and especially if we're not
(34:49):
changing those tire pressuresfrom road transport to infield,
if we're decreasing that speedor decreasing that load, we want
to be able to, as you said,travel safely down the road. So
if we're picking one or theother, we're probably not,
either not right at one or notright at both, and generally,
probably set up to be higherpressure than needed for that
(35:13):
field work.
Kapil Arora (35:16):
Definitely, there's a learning curve here, and we do
need to make sure that we startout small. We gain experience
with one system, understand thelimitations of the system and
how it works and what whatpoints we need to stop at in
that operation, because now theoperation has to have a few
(35:40):
pauses in between to deflate,and then back inflate, and then,
if need, deflate again. And thenand get a good understanding of
that and get a good sense ofcomfort in doing it, before you
decide that you're going to putthis on every piece of
(36:00):
equipment. I would, I wouldcaution, because you need to
have that experience, and youneed to learn about it. So one,
we stay safe on the road. Andtwo, when we are in the field,
we are not damaging those tires,because we still want our tires
to work, and radial tires arenot cheap
Tony Mensing (36:22):
We want to make the most of our investment there
too, right?
Kapil Arora (36:25):
Yes, absolutely, yes.
Tony Mensing (36:26):
And I guess kind of to go along with that there
are probably for everyoperation, some some specific
applications that may be ahigher impact to look at being
able to have a more significantimpact trying to mitigate that
compaction, right? So like Isaid, one that comes to my mind
(36:49):
is, particularly in the fall, wehave high loading from grain
carts or moving the crop off thefield. And then in the spring,
like I mentioned, those centerfor front fold planters, some
applications where we have areally large disparity from what
we're asking of those tires,from the road transport mode to
the field mode. So might be ableto pick out a couple operations
(37:13):
that are able to they might havea bigger piece of the pie as far
as the compaction damage that wemight be doing.
Kapil Arora (37:20):
Yeah. So definitely, where we have,
especially those things, wherewe have higher loading or higher
pressure on the soil, thosewould be the biggest impact, if
we are able to reduce thepressure on those. Again, we
were talking about this earlierfreeze. Thaw doesn't help with
deep compaction, and thosebigger pieces of equipment may
(37:42):
very well be the ones creatingdeep compaction. So if we can
help and minimize and keepcompaction shallower, freeze
thaw will help. Many people haveseen benefit from tillage as
well. You could do tillage, buttillage points only go so deep.
(38:03):
If you try to go deeper, thenyou yourself need more tractive
force for that tractor to beable to.
Tony Mensing (38:10):
It can be a double edged sword, right, and you can
actually do some compactive harmif we're operating in conditions
that aren't conducive to breakup those soil particles if we
don't have the right moisturelevel, we could actually be
doing more damage than we'redoing good.
Kapil Arora (38:28):
And then I've heard folks use cover crops as well to
help with some of thecompaction, all of these
practices are there to helpmitigate what compaction that
would have happened. But again,if we can keep compaction
shallower, and this technologyof CTIS definitely looks like
(38:49):
the one that can help.
Tony Mensing (38:51):
It makes it possible to do what we've known
for years we should do, which ismanage our tire pressure, right?
So it's it's another tool thatallows us to do the things that
people like you have beentelling folks they need to pay
attention to for a long time. Itjust hasn't been nearly as
convenient as it might be withsome of these systems to make
that happen in the past.
Kapil Arora (39:12):
Right. And previously, not having a mounted
system and having air availableat the shop created an issue,
because now, if you are farminga field that's two miles down
the road and you don't have ashop there, you just have a
field there, or you're justrenting it, it created a
logistics issue of, how do Imanage my tire pressure, and how
(39:33):
do I do this? And then when Iget done, then somebody has to
bring a compressor on a truck,pickup truck, and wait there and
do it. And basically, folks havetaken that system that was fixed
in the shop or was on a pickuptruck and mounted it directly
onto the tractor or theimplement and given us the
(39:57):
controls in the cab to be ableto push buttons from. On the cab
itself and be able to do it.
Tony Mensing (40:02):
Sure, and you're doing the inflation and
deflation on the go, basically,right? So not only do you have
the system on the machineitself, but it's not like we
have to stop necessarily and getout to make that system work. We
can be traveling as it's doingits job to you, as long as we're
cognizant of making sure that weallow it enough time to get to
(40:26):
the point that we need it to beto operate. Right?
Kapil Arora (40:29):
Yes, if you are careful and have accounted for
all the variables, you could doit on the go, and
Tony Mensing (40:36):
that'd be something maybe to discuss with
the equipment supplier that youwould look at for one of these
CTIS systems.
Kapil Arora (40:44):
But definitely I'm not the expert on CTIS system. I
do know how the system works andoperates, and yes, you should
discuss all those options withthe provider, with the
manufacturer of the CTIS systemas to what's the best way to
operate them if you are notwanting to stop or pause at all?
Tony Mensing (41:07):
Sure, and there's lots of questions to learn
answers to, hopefully, at somepoint, the deep compaction is
something that I think maybe wehave some more questions than we
maybe even have answers on rightnow, for people that want to
have one of these type ofsystems, or look at this as an
option to help them mitigatecompaction, lots of tire
(41:28):
options, multiple CTISsuppliers, lots of different
pieces. But I guess where I kindof come back to is it's not
necessarily new for people toknow how important tire
inflation pressure is, butagain, this allows you to be
able to manage that a lot betterthan we've been able to in the
(41:48):
past, to physically be able tomanage it, versus having to pick
a compromise somewhere between Ireally want to be here for my
field work and I need to be herefor my road transport or
whatever the whatever thebookends are on that we can work
for the situation that we haveat hand instead of trying to
compromise between two or threedifferent levels.
Kapil Arora (42:11):
Yeah, and I think as you mentioned, tire companies
have been publishing those datafor however they do their tire
testing, and they understandfrom their manufacturing what
kind of loads those track tirescan handle. So the data is
available from the tiremanufacturers, and if you're
(42:33):
buying it through a dealer, youcan very easily request that
information, and they canprovide you with with the
tables, and you should be ableto go off of those tables,
Tony Mensing (42:45):
Sure, yeah. Well, tons of more in depth
conversation that I think thatwe could have, or even bring in
some other folks to discussfurther on this topic that tire
technologies themselves. Lots tomaybe know and understand about
compaction that we don'tnecessarily even know today.
Some of the other potentialmitigation practices, cover
(43:07):
crops, like you mentioned, thereare lots of questions and some
answers, but some morediscussion that we could have on
that. But I think, I think fortoday, you've done a really
great job of covering kind ofthe basic overview of what
compaction is, why we need tocare about it, some potential
ways to mitigate it, knowingthat we're not going to be able
(43:28):
to eliminate compactionwholesale. And I guess I would
welcome a last comment or two,and then I think we'll probably
wrap up for today save
Kapil Arora (43:39):
for another episode. I think if we invent
implements that are operated byhelicopters so we have no soil
contact, maybe that will be asituation where, where we may
not have any compaction, or verywell, even in that you still
have the implement on theground.
Tony Mensing (44:01):
as long as we have some kind of equipment soil
interaction, we probably havepotential for compaction.
Kapil Arora (44:07):
I would agree with that.
Tony Mensing (44:08):
Yeah, well, thanks again for for participating on
the podcast with me today,Kapil, and again, I'm Tony
Mensing field agriculturalengineer with Iowa State
University Extension andOutreach. And to the listeners,
thanks for tuning in to thisepisode, and if you have follow
up questions or comments, feelfree to reach out to anyone on
the ISU Extension Outreach agengineering team for some
(44:31):
further discussion or furtherinsight on compaction. You can
search the Iowa State UniversityExtension and Outreach store for
publication 3180, which isUnderstanding and Managing Soil
Compaction, and hope to have youback on another episode of
Engineering Your Farm at a laterdate. Thank you.
This institution is an equalopportunity provider. For the
(44:54):
full non discriminationstatement or accommodation
inquiries, go towww.extension.iastate.edu/legal.
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