Compacted soils

[lhampton]

What do you do (if anything) when asked to deal with a compaction problem in a heavily landscaped area. Radial trenching, partial soil replacement are not an option because of damage to the landscape and the cost involved in repairing the landscape.

We still go out and drill 2 inch holes all over the place but I am becoming convinced that this is not effective. In part because of the limited amount of soil volume affected, also because of our soil. Houston Black Clay is some heavy, sticky stuff and difficult to manage.

Have you guys come up with anything?

Louie Hampton

 

[John Paul Sanborn]

I've done a few jobs with my air tool so far. In some they did not want to do trenching because of the long term effect to the landscape. It is hard to get the trenches to look like the yard was prior.

On some I have done very small trenches, in others verticle mulching and aeration.

One has agrees to annual visists to poke deep holes and refracture the soil. Sort of an intuitive thing I've done too is to put native earthworms into the holes with the amendments. I work with a landscape aquaintance; air work in the fall and top dress in the spring. Return visits will be based on how the topdress turns out in the sumer. I sort bill it as a long term minimaly invasive soil remidiation/amendmant prosess.

My theory is the deaper you can get the the soil changed, even localy, the better water penetration you will get and from there drough tolerance. Studies have shown that with clay soils air fracturing without amendment will recompact, my hope is that the introdution of macrofauna will move the amended soils out into the fractures, holding them open for fine root propigation.

Wulkie's application of his water sausages, I call perk irrigation, he thinks that there may be deep ground water wicked up, so maybe deep columns of sandy loam will do this to to a certain extent.

IMO any fraturing of poor soil and addition of organics will benefit the trees. The less invasive we are the more often we need to return.

I would add into this irrigation that is more of a drench then a spray, so that a large volume over a long time for good deep penetration is needed. better gass exchange in the soil and longer retention. Thsi can be done with longer periods in between then the current surface sprays.

 

[TREETX]

What kind of tree is in question??

I vertical mulch fairly often but is always when dealing with soil compaction in relation to Post Oaks.

I have had good results but these tree are in loam or sandy loam.

I have heard that vert mulching doesn't work at times with clays because the 2 inch holes harden up after being drilled and thus exposed to air. The result is a hardened column that just holds water. AKA - Glazing Effect

Let us know what you come up with

Nate

 

[lhampton]

Really haven't come up with anything except questions so far.

Was out using the Airspade on a construction site a week or so ago. Hit a severely compacted area, crew was there doing drill aeration and fill with compost, they drilled into the compacted area with a two inch auger bit thinking it would loosen the soil and speed the operation up a bit. It didn't. In fact the area immediately around the drill holes was even harder to blow out.

Got me started asking questions again. Send me your email and I'll send you the pictures and you can tell me what you think.

I'd post some of them... if I could figure out how.

 

[treeist]

I blast holes with my root feeder attachment I can add stuff too. one foot centers 3 ft deep, as possible.

 

[TREETX]

That was a really good short report showing the problem. I have never had to deal with clay like that. It is cool how you could document the glazing of the hole walls and how resistant they were to the air spade.

I think glazing is only a problem when particle size goes down.

I only use vert mulching when dealing with soil compaction on species that grow on sandy soils. By this, I mean post oaks and loblolly pines. I have had good success on these types of sites.

Try contacting someone at the soil science dept at A&M. See if the academia sector has any suggestions.

Your pics made it painfully clear how pointless augers are on heavy clays.

 

[John Paul Sanborn]

I put Louie's paper on my "website".

Click here http://home.wi.rr.com/sanbornstrees/ Then click on "soil compaction" it is a Word.doc, so you need to have MSWord to open it.

 

[lhampton]

I put Louie's paper on my "website".

Cool, thanks.

I've gotten a few responses so far. There seems be agreement that there are no quick fixes, which I understand. With clay, there is no one time, long term approach, which I also understand. There seems be some agreement that the Airspade is a superior tool, but that there may still be some limited benefit to drill aeration. How much and how long is questionable. I still think there is a better approach out there. I just need help finding it. It makes me uncomfortable to see us take peoples money for something of questionable value.

I would still like to get thoughts from others.

Louie Hampton

 

[John Paul Sanborn]

The short term value is there.

It is just that compaction is a microscopic event, we need to wait for the worms (et al) to crawl in and out for true remidiation to take place.

We can excelerate this by making the environment better for them; adding organic, increasing average particle size, regular fractureing of the soil so that the can move around better.

The best, cheapest fix will always be the addition of surface organics. Not just getting rid of you chip load, or selling an aesthetic mulch, but a humusy compost, then the aesthetic (high margin) chip mulch. I have seen small studies that show an 8 fold increase in macrobiota under these layers, along with the increase of fine root development.

IMO though we need to add to this program scheduled basal area maintinance to ensure that we are not creating conditions that will lead to girdling root, fused root plate, and poor flair/palisade development.

If you have a noticable increase in color, vitality, fine root devlopment, water penetration... then you are providing a benefit to the customer. You are just trying to find a way to do this without disturbing the aesthetic value that client has already established. this will take time and repeated application.

Soemtimes it will not be possible and then regular micro amendment of the soil may be needed.

One thing I have thought of (nad mentioned a few time)is a masserating pump and injecting a slurry of organics into the soil. One problem the people with the dry injection system rased is that you develop hyrdological discontinuites this way. I think the macrobiota would be able to take care of this, and it will keep the clay peds from glomming back togeher.