Soil Aeration Experiments| Grade Changes| Compaction| Decompaction

Eric Frei

Is soil aeration a myth like wound painting and concrete filling hollows?

Some PDF's attached which seem to indicate that there's insufficient evidence to support the often prescribed aeration theory. In fact many test show contradictory information.

Should you come across any validated scientific data then please add it here.

For starters a few PDF's attached, well worth a read.

Could make this guys idea and product a real winner.

Lazyman Soil Products| Know them? Use them?

Also, tons of info via this link. Warnell School of Forest Resources: Service and Outreach: Publication Library: Community Forestry: Trees and Soil Compaction[]=12

A very nice PDF (9.8mb) from Morton Arboretum Soil Science on this link well worth a read about urban soils.

Attached Files

	soil aeration fill test.pdf (12.0 KB, 591 views)
	Soil Aeration root test.pdf (45.2 KB, 404 views)
	Soil Aeration test.pdf (694.0 KB, 243 views)
	soil fill effects tree growth aeration.pdf (306.5 KB, 416 views)
	soil grass crop aeration compaction tests.pdf (69.8 KB, 245 views)
	Soil ODR Tests healthy vs declining oaks.pdf (304.7 KB, 186 views)
	Effects of soil decompaction and ammendment- terravent.pdf (125.3 KB, 520 views)
	soil compaction experiment.pdf (62.6 KB, 235 views)
	deep ripping decompaction grasses.pdf (585.1 KB, 162 views)
	myth-soil_amendments.pdf (111.4 KB, 179 views)

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Knotahippie

Ekka, this is real good stuff!

basicly compost tea.(mmm my favorite)

check out this compost link by John Fergusen...

http://www.riveroaksgardenclub.org/D...sBlackGold.doc

I have heard Dr. Frank Gouin say (with big wide eyes!) that it is humic and fulvic acids that are big compaction remediation agents.

I think alot of tree/root problems (depending on many factors) start with grade change/compaction as the lit. you provided explained.

Seems like compaction is a problem for trees depending on many factors and for some cases, air fracture combined w/compost with can be a really good method.

http://www.forestry.iastate.edu/publ...pdf:gday_mate:

Eric Frei

Also seems from documentation that the top 6" of compaction make the most difference. They found soil conditions deeper were better but tree still declined, the top 6" is critical. Interesting part was when aerated compared to other methods and control, aeration didn't have any great advantage and those that were treated with compost tea did better than those which were just aerated.

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Knotahippie

Have you read Landscape below ground I and II?

Some cool research about compaction in both books.

Frank Gouin is a legend too. He had examples from Washington DC monuments and others, alot of foot traffic, no nutrient cycling w/lawn, etc..

Radial trenching methods/compost looked extreme but worked in a specific location...

aeration looked to me like least harmful.

I heard air for summer, water for winter. I use a garden hose/pvc in the winter, cheap for me and the customer...

Gets those acids where they need to be, that pvc air tube BS is for the birds...

Knotahippie

Just by fracturing soil slightly and adding a little LOW nutrient compost, water infiltrates better, O-A layer/ gets to where it needs to be...call it aeration or what ya' will,

"Air fracture" and the increase of pore space really makes soil drain better, makes it easy for important fine absorbing roots to grow.

Many plant's don't like stagnant water.

It takes about 8 passes with a backhoe to cause severe damage to roots (landscape below ground I-II).

With so many problems assoc. with const. and compaction wev'e gotta' have methods to reduce damage quick!...suggestions?

Attached Files

	soil_compaction_tree_roots_coder.pdf (27.4 KB, 146 views)
	SOIL_COMPACTION_randrup.pdf (67.0 KB, 182 views)

willem

Very interesting. The company I work for has done grade changes with mulch/compost to create a bigger rootball for transplantation. By doing it in small steps divided over a couple of years we created a layer (50 cm> thick) of extra rootball.
See this clip In this clip you see the tree had a very shallow rootsystem. The gray sand is seasand that is spread out on the the peatboggrounds to make building possible.
This sand doesn't sustain roothgrowth.

We use soil aeration together with a product made up of stone fragments, clay and fertilisers. The product is used in parkinglots and underneath roads. It has enough strenght to sustain maximum trafficgroundpressure and still it holds its structure. Rooth growth is very good in this product.

Sean Freeman

Your version of a structural soil by the sounds.

willem

Sean, please explain structural soil??

Sean Freeman

Developed in the US, sometimes called dirty rocks.

Structural_soils_updated081202.pdf

CU-Structural%20Soil.pdf

I have a copy of the urban soils primer from the US Dept of Ag very good basic info on the physical structure of soils and how we alter/amend them during urban development etc... its 8.6Mb and below is the link to download it.

http://www.treeworld.info/manualuplo...oil_primer.pdf

Knotahippie

Read "Lessons in Nature" about 5 times...cool book, if I had to pick one book...

Saw Malcom Beck at a conference in CA. wher he spoke on soil/health.

Took me a while to find the article that inspired me to use "water wand" tech.

Herbs for Texas: A Study of the ... - Google Book Search

What do ya' think?

newguy18

if one was careful[Bill takes a deep breath]it might be possible to lightly break the soil with a small rototiller.Keep in mind this is just an idea and i know how quickly it can damage roots if done carelessly.

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Knotahippie

I'm not that good with a rototiller and considering 90% roots are in (roughly) top 1' ... I'll stick with a good layer of chips instead.

newguy18

Just a thought for heavy clay soils,i run into them occasionally.

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Knotahippie

I guess I usually walk...

newguy18

Walk?you mean you usually walk away from those kind of jobs?

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Knotahippie

Don't do rototillin' not to say I wouldn't...don't need to.

newguy18

Okay gotcha,just a thought,i either do pruning or removals,mostly removals.Theres just no market for much of anything else here.=(

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Eric Frei

Bill, rototilling heavy clay soils is old school, ripping is new school.

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newguy18

okay,won't do it then,what is ripping exactly?

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Eric Frei

You know, like a tine or hook in the ground and it makes furrows.

Advantage is less compaction and it doesn't turn the soil profile. They usually go around 300mm to 400mm deep and to be done in dry conditions only.

But you cant really rip around tree roots.

Looking over farming stuff seems the organic method and special crops, crop rotations with different root maps work best.

Also it seems, compaction is really more a surface issue, top 100mm most affected.

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Knotahippie

Found some compaction data for trees from AU.

Attached Files

Compaction, AU trees.pdf (619.5 KB, 392 views)

Eric Frei

Very interesting, for the record 1MPa=145psi

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willem

Thanks for the info Sean.

I have some pictures of a project I was working on last week. The local goverment in this town invests a lot of money in the planting of new trees.
After the roadreconstruction there will be trees planted in this street. Each tree will have acces to 50 m3 of our granulate mixture (structural soil) also an aeration system is installed and the seperate aeration systems are connected.
Almost 900 tons total!!

These pictures show my work. The aeration system which is then buried with the mixture



The trucks bring more of the mixture



This picture you see roadconstruction in a later stage with the lights and curbs in place. The trees will be planted in the narrow space between the curbs in between the lights.


The next part on which I was working.


In the last picture are two most important tool. They are a little bigger and heavier than a 020 chainsaw.

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Sean Freeman

Great pics Willem, Brisbane City Council (BCC) undertook a very similar project along two urban streets some time back, saw the installed trees two weeks back and they look pretty good. They didn't install the sub soil aeration system though.

willem

In heavy clay soil we use this method.


This method is already discussed in other threads but I'm convinced it works. Although the effects are reativly short lived and treament has to be repeated. We break the ground and inject fast working fertilizers to enhance rootgrowth. I've seen trees going from almost firewood to a tree in a reasonable condition by repeating the treament twice every year.
This can be combined with mulching for long term effects.

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willem

If you ever have the change of taking some pictures of such a project I would be very interested to see this kind of work from the other side of the planet.
By the way roothgrowth and tree establisment are very good in this stuff, let alone the money my boss is earning with it.

Knotahippie

I like the idea of using high pressure air/water to increase macropore space.

scooter1962

I have used the Terralift machine for soil decompaction over many years. (It was stolen about two years ago)

It is a tool that always had a lot of animated discussion about whether it worked or not, but, from experience, I have to say that it does open up compacted soils.

Like most of the air operated tools, it works better in a heavier soil - sandy soil just blows out.

Pre water restrictions we would often run a hose down the decompacted hole, and never saw the water come to the surface - all ran down the cracks made in the soil profile. ( We even hit a 4" fire hydrant once, now that was a lot of water!!!)

I often wonder why these sort of tools are not more common in Aust.?

Eric Frei

I have been doing some more research in this area.

Also you might want to check the original post as I have added some new PDF's and a new link to a great 9.8mb PDF

One of the key things to note about compacted soils is that inserting a solid tube or tine increases compaction. Whilst you have a hole you actually have not heaved or removed soil so "squashed" soil adjacent to the hole you made.

Hollow tubes or tines like a corer on golf courses removes soil, you have the same volume but less mass now. ripping does the same, it increases the volume of soil.

So if you insert a probe into the soil, hit it with compressed air and there's no heave or increase in volume has the density changed? Nope.

In effect to decompact the soil you need to decrease it's density or mass for the volume..... if 1m3 of uncompacted soil weighed 1500kg and then you drove over it wet with a 10 ton truck 100 times and re-weighed it taking 1m3 of soil you'd find now you'd have perhaps 1800kg of weight. In effect the particles have been rearranged and pores made smaller or removed.

Now to decompact it the volume has to increase.

What some studies have shown is that roots exploit tiny cracks and fissures, they take the path of least resistance. I have spoken previously about literally getting an auger drill bit and drilling the ground creating holes, which removes soil. Then getting a steel rod or something and roughing up the edges of the hole. That will create fissures for roots to go down, it will allow air and water down along with organic matter. We cant rip around tree roots but we can drill verticle holes removing mass and allowing microbes to work deeper.

Of interest is also some evidence showing grasses work better than mulch to decompact. Soil resistance measured with a penetrometer in a lawned area does better than a mulched area. Grasses are deep rooting and have recently shown as more important to the salinity issues in the MDB than trees as they go deeper to extract ground water.

I would envisage that tall clumping grasses could be under planted with trees to assist in soil decompaction, both could live harmoniously and be mulched. That environment could be treated with compost tea or similar, a biological concoction of bacteria and fungi.

Having done some penetrometer tests I can say that it's very rare you are going to shove any 1/4" dia piece of steel rod into the ground some 30cm deep. However having a look at the environment, what grows with what naturally it's easy to see tall grasses in coexistence with Australian trees in dry sclerophyll forests. Some of the naturally occuring forests have little to no top soil, you have seen that I'm sure, sometimes when I drive through a highway cutting I'm amazed at what trees grow in. Fine roots do penetrate the cracks though.

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Eric Frei

From Tree Roots in the Built Environment 2006

Tests and comparisons were made over 3 years in a variety of soils using Terravent and Grow Gun and results shown.

In the link above you can read for yourself what the outcomes were. As expected in a heavy soil (clay) questionable improvement occured and obviously in a sandy soil improvement was gained.

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