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cracks in clay soil are threatening my young trees !

 
Levente Andras
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Location: Harghita County, Transylvania, Romania
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Hello Permies!

I'm struggling with a new problem: young trees planted 2 years ago are seeing their first dry summer, and are suffering not so much because of the drought (not too severe by local standards) but because of the horrible clay soil, where huge cracks are forming due to the hot & dry weather.

The cracks are over 2 ft deep and 2 inches wide in some places. Sometimes, a long crack leads directly to the tree's root, or surrounds the tree so that it looks as if in the middle of an island. The trees are mulched with mushroom compost and gravel, but that only provides some very limited protection.

Most trees are feeling the stress, some are dying.

Watering is not an option (2.5 acres of land with limited water resources).

Any ideas?

Levente
 
leila hamaya
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wet mulch?

if you can get some moist/wet straw, leaves, woodchips, etc out to them i would cover them up with a layer of mulch. stuff it into the cracks....
 
Levente Andras
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Location: Harghita County, Transylvania, Romania
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leila hamaya wrote:wet mulch?

if you can get some moist/wet straw, leaves, woodchips, etc out to them i would cover them up with a layer of mulch. stuff it into the cracks....


I have a large heap of spent mushroom compost, which I intend to spread over the surface, hopefully some of it will end up deep inside the cracks and provide some temporary relief. It won't be an easy task, given the size of the plot (I wrote 2.5 acres, actually that's a mistake, it's 1.5 acres)

However ... I need to find a long-term solution - rather than a temporary patch-up - to increase resilience and reduce the chances of cracking in the future.

Only 2 months ago, after a wet Spring and early Summer, the soil was full of moisture, thanks to my swale system (and the high clay content of the soil, of course). My swales got filled several times between March and May. After two months of drought, there's no trace left of all that moisture...

As I explained in an earlier post, 2 years ago I tried mulching with hay around the trees (I have plenty of alfalfa hay), but I had to give up on that idea because of serious threat from voles.

Then last year I mulched trees individually with pea gravel. That has been helping somewhat, but when the cracks get as severe as this year, the gravel just simply falls through the cracks.

So I'm looking for design ideas, focussing more on the longer-term results (significant alleviation of the problem in 1, maybe 2 years' time) rather than on immediate relief.
 
Steve Farmer
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Location: South Tenerife, Canary Islands (Spain)
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If you get the mulch into the cracks then next drought it shouldn't crack as much. If you can get some sand in the cracks as well/instead that's also a good thing.
 
chip sanft
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Location: 18 acres & heart in zone 4 (central MN). Current abode: Knoxville (zone 6 /7)
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I second the mulch suggestion.

We have heavy clay soil that cracks when it's dry. But the areas where I'm building soil through mulch and green manures don't. I'm not sure how much of that is due to the mulch retaining water and slowing drying, how much is due to the additional organic matter, and how much is just random. But my experience suggests mulching your trees could help. Top-dressing with stable scrapings, for instance, might be useful without too much expense, and it would be doable on 1.5 acres.
 
Cristo Balete
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Levente, I've got your problem around ever perennial I ever planted. Those cracks are from gopher tunnels, used by voles, mice, snakes and anybody else who wants to use them. They are coming there because you are watering when all the other clay is dry. Mulch will only cover up the top so you can't see just how badly it's going under there.

I have had good luck filling the cracks around the trees, first with about a couple inches of compost or manure, for your tree health, then with 3/4" gravel up to the top. They will dig right through any organic stuff you put in those cracks, so it's got to be a deterrent. They don't like large gravel. Pea gravel won't work. Use the skinny end of a shovel handle to pack it in there. Then water well, then cover it with mulch, but pull it back every couple of days in case the gravel is dropping or they've gone around it. Add more gravel.

Then you've got to stop them from coming that close to your perennials. Plant native weeds that they avoid under the tree in North, South, East, West positions within 1 foot of the trunk, and then about 18" out from that, or put daffodil bulbs around the tree/plants about 6 inches apart.

I use a lot of thick mulch, but they can do a lot of damage under there if you don't pull it back when you are watering a lot, and watch what they are up to.

 
Cristo Balete
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The thing about voles is they don't kick the dirt up like gophers and moles do. Maybe it drops lower in the cracks, or they shove it somewhere else, but I never see signs of voles kicking up dirt. There's just these big gaping cracks as the clay dries out. I took a photo of how they surrounded a grape vine in a chicken wire basket, there wasn't an inch of dirt above the surface to imply they had done what they've done. It was under the mulch, and I didn't even see it until I pulled it back. The grape wasn't suffereing yet, but it would, just sort of go into neutral. They never seem to sleep, those little stinkers.

 
Marsha Richardson
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Our soil is a very high quality clay that makes excellent pottery when dug up from anywhere on the farm. We use a lot of mulch and compost piled on very deep and it has been working. Our little friends the earthworms drag it down into the clay as it breaks down. The key is to NEVER leave it exposed. We have also been cursed at our place with the dreaded voles. I waged pitiless war on them for many years but they can reproduce faster than I can destroy them. Then I read sepp holzer's book on how the voles actually loosen the soil with their tunnels and that if you leave them alone the predators will move in and control their numbers. Soooooo. I always made sure that the bark of my young trees was protected by a ring of hardware cloth (wire) out about 4 inches from the trunk and mulched heavily from that space outward. The voles leave little tunnels all over that the rain washes compost deep into the soil and even better . . . black snakes, copper heads, owls and grey foxes have moved in and we have noticed a drop in overall vole predation throughout the property. That first year was very nervewracking. We put in brushpiles when we clear scrub that provides habitat for the snakes. When the piles break down, we pile dirt on them and jump around on it. Excellent place to plant new trees! Voles are also repelled by castor oil and any part of the castor plant. If you can grow them (danger, highly toxic), they make an excellent chop and drop around young fruit trees.
 
elle sagenev
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I'd suggest you get cats and lots of them for your vole problem. We've waged war on them and lost many times. We still haven't won but we are in the cat process. Our neighbors have 0 voles thanks to their cats.
 
Marsha Richardson
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I'm sure that domestic cats, one of the most efficient and non-selective predators on the planet next to human beings, would be great at getting rid of the voles ...... and the squirrels, chipmunks, chipping sparrows, blue birds, quail, young snakes, frogs, and anything else they can get their little claws into. Although my other half loves cats, I do not believe in inserting non-native predators into an ecosystem. The voles keep digging their tunnels, the snakes eat some, foxes eat some, we all just kind of try to get along. I protect the young trees and interplant enough extra plants to ensure that even with the voles, there is enough to go around. Now if the blackbears would only leave my berries alone . . .
 
Cristo Balete
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Marsha, yeah, sounds exactly like what I've got. It's true, the gophers, moles and voles can really turn that hard clay into beautiful stuff. And as long as they stay away from the plants, I have found it to be helpful, especially collecting gopher mound dirt as soon as they kick it up. It's magic for planting transplants in. Worth dragging buckets of it to wherever it's needed. Although those wide-open air tunnels have to be dealt with regardless. Yeah, the really thick mulch works so well for so many things and is easy to do.

I learned from a vineyard caretaker that he always leaves the burrows and main tunnels in place so he knows where they are, doesn't try to destroy them because they will just dig more tunnels in places that could be even worse. It is amazing to dig into one of the main tunnels and see how smoothly the walls have been brushed against for maybe even centuries. I can fit my forearm into most of them.

I am experimenting with one thing. I have many tall pieces of skinny rebar at both ends of all the rows, and a large cottage cheese container or yogurt container hanging upside down over the top of the rebar, and the wind makes it go clickety click most days and at night. I am not seeing much activity as I usually would. I also put extra poles where I see activity. This is the cheap version of the clicking wind gopher annoyers you can buy. They don't look so great, but if they work I'll paint them and make them a little less prominent. It might just be a slow gopher year, but I will try it for a couple more and see how it goes.

 
elle sagenev
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Location: Zone 5 Wyoming
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Marsha Richardson wrote:I'm sure that domestic cats, one of the most efficient and non-selective predators on the planet next to human beings, would be great at getting rid of the voles ...... and the squirrels, chipmunks, chipping sparrows, blue birds, quail, young snakes, frogs, and anything else they can get their little claws into. Although my other half loves cats, I do not believe in inserting non-native predators into an ecosystem. The voles keep digging their tunnels, the snakes eat some, foxes eat some, we all just kind of try to get along. I protect the young trees and interplant enough extra plants to ensure that even with the voles, there is enough to go around. Now if the blackbears would only leave my berries alone . . .


My LGD's have always kept every other predator away. I'll plant some cats!

eaten mulberry.jpg
[Thumbnail for eaten mulberry.jpg]
They just piss me off!
 
Marsha Richardson
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Any my Korean Jindo keeps predators away, including cats. She does try to dig up moles but it just turns over soil and our clay needs all the help it can get.
 
Cristo Balete
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elle, you probaly know cats need to be raised by a barn mom if they are in a rural setting, and that takes several months, not new kittens. They need protection from big predators, coyotes, bobcats, foxes, mountain lions, hawks, owls, especially at night. They wouldn't make it where I am. Sometimes people dump pets out here, or squirrels in those Have a Heart traps, and they don't last more than a week or two, are too scared to be taken in by strangers.

And if you do get the right kind of hunting cat, they should only be given a morning meal, so they will get hungry and go hunt for the rest. But that puts them out at night, and they need places to get under for safety.
 
elle sagenev
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Cristo Balete wrote:elle, you probaly know cats need to be raised by a barn mom if they are in a rural setting, and that takes several months, not new kittens. They need protection from big predators, coyotes, bobcats, foxes, mountain lions, hawks, owls, especially at night. They wouldn't make it where I am. Sometimes people dump pets out here, or squirrels in those Have a Heart traps, and they don't last more than a week or two, are too scared to be taken in by strangers.

And if you do get the right kind of hunting cat, they should only be given a morning meal, so they will get hungry and go hunt for the rest. But that puts them out at night, and they need places to get under for safety.


We took in 5 kittens that weren't even weaning age when their mom was hit by a car. They were hand fed and kept indoors until they got big enough to go out. Then they were out in the barn with the birds. We took 2 to the pound after 2 died. The third one we couldn't catch. We see her from time to time. She stopped eating the food we left for her. We've seen her catching mice and such. She is a feral cat, that one, and a good cat to have about. We do nothing special for her, though since I started them in the barn she does go back there, and it's protected.

My area has coyotes but otherwise they do ok. The feral cats in our area are all black. Perhaps that is what has kept them from being eaten by coyotes. Beats me. We have a lot of ferals in our area though.
 
Cristo Balete
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elle, so you know how that goes. That's a good theory about the black being a safer color.

I was just realizing the other day, I think I can tell when the economy is going to tank, people start dumping their pets. I hate it when that happens, because most don't stand a chance. They just don't have the rural smarts that the wild predators do. I've tried and tried to catch some cats, to befriend them and keep them around, but they are too terrified. I wish people would get the message that dumping them is a terrible mistake, for the most part.
 
Levente Andras
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Update: 3 days ago heavy rains arrived and the ground got so wet that the cracks have disappeared completely. However, the trees are looking pretty shabby after the long dry spell.

Anyhow, I thought I'd share another thought regarding design for clay soils.

Some of my trees were planted along the swale berms. To be precise, I planted them at the base of the outer side of the berm. Obviously, the berm is 'fill' and hence it is softer than the surrounding ground. However, being at the base of the berm, the planting hole was dug mostly into hard, undisturbed clay. In other words, although the tree does benefit from the higher moisture content thanks to the swale behind it, it cannot take advantage of the soft soil that can be found in the berm.

At the time, I decided to plant at the base of the berm for two reasons: (a) planting on top of the berm would have exposed the roots to easy attacks by voles; (b) I was concerned that if planted on top of the berm, my trees would be more exposed to drought, especially in the event of a long hot & dry period like the one we experienced this summer.

So here is the issue: swales are supposed to be planted with trees - and Bill Mollison suggests that the planting should be carried out right after the swale has been dug; however, in clay soil, a freshly dug swale and its berm are not a great environment for planting.

The berm itself, when fresh and made of heavy clay, is a heap of large clods not unlike big chunks of soap. Try to plant a tree in the middle of those... You'll need to let the clods rest for a couple of months at least, so weather works them over and breaks them up a little, before you can consider planting on top of the berm. As for planting at the base of the berm, that's potentially even worse, because the undisturbed clay soil around the planting hole will remain hard and hence difficult for the roots to penetrate...

 
Cristo Balete
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Levente, well, the clay topsoil may have expanded back to the point where you can't see where the cracks were, but those tunnels that caused those cracks are still under there, and the roots of your plants are still going to grow into them and get munched.

I definitely agree with planting at the base of the berm because the gophers and voles will turn those berms into wind tunnels so fast you won't believe it. Trees don't really need soft soil, they just need damp soil, even if it's clay, which is down below where the sun don't shine So don't be too nice to your trees. Make them hunt downwards for nutrients, and get acclimated to the real ground you put them in, not just the fancy top stuff. You'll still need some kind of barrier between the dripline of the trees and the rootball. It will dry out again, and the whole cycle starts over.

What zone are you in? What's your average rainfall?
 
Angelika Maier
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Mushroom compost contains salt and that kills some trees.
 
Levente Andras
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Cristo Balete wrote:Levente, well, the clay topsoil may have expanded back to the point where you can't see where the cracks were, but those tunnels that caused those cracks are still under there, and the roots of your plants are still going to grow into them and get munched.

I definitely agree with planting at the base of the berm because the gophers and voles will turn those berms into wind tunnels so fast you won't believe it. Trees don't really need soft soil, they just need damp soil, even if it's clay, which is down below where the sun don't shine So don't be too nice to your trees. Make them hunt downwards for nutrients, and get acclimated to the real ground you put them in, not just the fancy top stuff. You'll still need some kind of barrier between the dripline of the trees and the rootball. It will dry out again, and the whole cycle starts over.

What zone are you in? What's your average rainfall?


I'm in Transylvania, Romania, Eastern Europe. I think mine corresponds to Zone 5. Cold winters, fairly hot summers. I don't know about average rainfall, all I can tell you is that we get precipitation throughout the 12 months. After 6 weeks of drought, it's been raining for almost a week now, and we got up to 25 litres per square metre (that's 1 inch of rain) on the wettest day.

I'm sure the little devils are still at work below the surface. I've been fighting them for 2 years now. Lost several dozen trees to them already (out of about 500 that I planted over the same period).

What kind barrier are you referring to? Barrier against voles? I'll be experimenting with wire netting for the next 'planting campaign'.
 
Levente Andras
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Location: Harghita County, Transylvania, Romania
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Angelika Maier wrote:Mushroom compost contains salt and that kills some trees.


I've read something to that effect myself, from a couple of sources (I think mainly contributors on other forums). I think these concerns are totally unfounded. Not sure what salts mushroom compost might contain that could be harmful to plants. It does contain gypsum, which as a soil conditioner should be beneficial to clay soil.

At any rate, theory is one thing, and practice is another. I have been using mushroom compost for the last 3 years. Been purchasing it from the same supplier, and have applied it in 2 different locations, with totally different types of soil, as mulch around trees of all kinds, soil improver in the veg garden, and fertiliser on grassy areas. It has had no ill effect on trees, and the herbaceous plants (including most of the vegetables) loved it. I do suspect that it renders the soil just slightly more alkaline, and a small minority of vegetables such as cucurbits do not seem to thrive in soil treated with mushroom compost.

L_
 
Cristo Balete
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Levente, a barrier as I said above, about the native weeds as a barrier, or daffodils or daylillies 1/3 meter around the trunk of each tree. I know you have a lot trees, but around the areas where it's the worst. Spread seeds you can gather from weeds that gophers leave alone. The tall spikey dock works great, as an example. There would be enough seeds from a couple of tall spikes to go around a couple hundred trees. Just notice which weeds they don't bother and use those.

Then you've got to stop them from coming that close to your perennials. Plant native weeds that they avoid under the tree in North, South, East, West positions within 1 foot of the trunk, and then about 18" out from that, or put daffodil bulbs around the tree/plants about 6 inches apart.



Mushroom compost was one of the greatest things I ever had the privilege to work with. When I had access to a mushroom farm, I got truckloads of it, it was stunning. I never had a seed started in it damp off. I love that stuff.
 
Cristo Balete
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Levente, I thought you would appreciate this photo. I pulled back the mulch near a fruit tree and found this crack. This is new this summer. That's a regular spoon in the crack to show some proportion, it would have slide down and out of sight, that's how deep it was. Filled it with large gravel, they should go around.

And I hope they will get hit on the head for good measure!
CrackInClayatFruitTree.JPG
[Thumbnail for CrackInClayatFruitTree.JPG]
 
Rez Zircon
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elle sagenev wrote:The feral cats in our area are all black. Perhaps that is what has kept them from being eaten by coyotes. Beats me. We have a lot of ferals in our area though.


Where I lived in the desert, we couldn't grow cats fast enough. But the main problem wasn't coyotes; it was owls. Any cat with white or light color on it got taken by owls real fast. Sometimes I'd find bits of 'em in the owl pellets.
 
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