swale headaches

Levente, you are right about the predator-prey population dynamics, and of course you know your place better than I do. I know nothing about Romania other than what my Romanian coworker friend Paul from summer camp told me when I was 19! But I would encourage you to look at Sepp Holzer's approach to colder-temperate climate animal control, in particular regarding voles. Also, if these animals exist despite what are likely to be your native animal's, neighbor's and predecessor's best efforts to exterminate them, they are probably pretty tough and pervasive. They will always come back, and the greater the vacuum the greater their eventual explosion. That or something just as bad, or worse. This is because the natural predators will die off before their prey is exterminated as you said, and this is when everything they ate goes nuts with exponential growth and then a crash.  

To be honest, I can imagine this is a bitch of a situation and I can't think of a good solution, though I wish I could. A Makah friend of mine spreads cat fur around the corners and entry's to his house to deter mice, and I wonder if that would do something around the vole burrows. That and research what your local small predators like for habitat and give it to them, especially owls which seem to be harmless to your crops. In addition, this would seem to make things lean towards the advantages of hugelkuture slightly off contour as Mr. Holzer does.

O. Donnelly wrote:
Perhaps a temporary fix is to create a controlled breach in all of your swales, so that if you have another major flooding episode the deluge will not destroy other parts of your garden.  Or build some kind of "flood gate" that  you could open at will.  [...]

Then you need to get rid of the voles.  Then seal their tunnels.  Perhaps something like a bentonite slurry would work?  Bentonite, aka montmarilonite, is a "shrink swell clay".  when saturated it will swell to many times its original volume.  Well drillers use it to seal off well casing.  it also works at the bottom of new ponds.

Thanks for the suggestions, OD

The "flood gate" idea is definitely a valid one, and I think I'll try to implement it.

Getting rid of the little devils is the difficult part, I've been working on it for the past 3+ years.

As for sealing the holes - that's an interesting one.  If I experience an "acute event" - like the one we had the other day, water gushing through a couple of holes - any sealant including bentonite clay will be simply washed away by the jet of water. So no sealing at that point - I just have to wait till the water level drops below the hole.  Once the event is over and water stops, I can seal the tunnel by simply collapsing it with a spade and tamping down the soft earth.

Ben Zumeta wrote:Levente, you are right about the predator-prey population dynamics, and of course you know your place better than I do. I know nothing about Romania other than what my Romanian coworker friend Paul from summer camp told me when I was 19! But I would encourage you to look at Sepp Holzer's approach to colder-temperate climate animal control, in particular regarding voles. Also, if these animals exist despite what are likely to be your native animal's, neighbor's and predecessor's best efforts to exterminate them, they are probably pretty tough and pervasive. They will always come back, and the greater the vacuum the greater their eventual explosion. That or something just as bad, or worse. This is because the natural predators will die off before their prey is exterminated as you said, and this is when everything they ate goes nuts with exponential growth and then a crash.  

To be honest, I can imagine this is a bitch of a situation and I can't think of a good solution, though I wish I could. A Makah friend of mine spreads cat fur around the corners and entry's to his house to deter mice, and I wonder if that would do something around the vole burrows. That and research what your local small predators like for habitat and give it to them, especially owls which seem to be harmless to your crops. In addition, this would seem to make things lean towards the advantages of hugelkuture slightly off contour as Mr. Holzer does.

Ben,

The vole population was boosted when my plot used to be part of a larger field of alfalfa for 7 years ... voles love alfalfa, not only as a perennial food but also as a tall herbaceous cover that protects them from birds of prey. I've managed to change the make-up of my plot's herbaceous layer somewhat (=less alfalfa, more grasses), but the adjacent field is still alfalfa... so I have a constant supply of voles from next door...

As for Sepp Holzer's Huegekultur... I'd say that's a no-no when voles are a concern.  Any mound / berm / raised bed will attract voles like a magnet.  I'm saying this from experience.

Tyler Ludens wrote:This may be a completely ignorant question - but how does temperate food forest herbaceous layer differ from subtropical herbaceous layer?  I see above in the thread people continually battling the herbaceous layer, whereas Geoff Lawton in his subtropical food forest, seems to welcome a particular kind of herbaceous layer which he terms "control through rampancy."  Is there not a way to replace the plastic layer with a desirable herbaceous layer?  Is the difference that the above examples are of a "permaculture orchard" and not a food forest, so there is no interest (or no need) for the different layers?

Firstly, I prefer the phrase "forest garden" - I think food forest sounds so ... utilitarian !

Secondly, I'm planning to create something that's closer to a forest garden than to a permaculture orchard. Let's say, something in between a "forest garden" and a "pleasure park".  Imagine contour swales, planted densely with trees and shrubs, behaving like very lush and very productive hedgerows; and the interswales, wide corridors receiving full sunlight, which can be converted to annual/perennial vegetable production if/when needed. Alternating zones of humidity and dryness, light and shade.

As for the herbaceous layer... I think you're asking a very good question.  I myself have mused a lot about the applicability in temperate climates of Geoff's sub-tropical strategies.  Then I stopped as I realised they were not helpful in my case.  

From what I recall from Geoff Lawton's videos, I think he prepares the ground (with the "chicken tractor"), then seeds it with some type of "rampant" legumes, then plants his trees into the ground covered by the already rampant leguminous layer.  

Initially it sounded good, and it sounded tempting, especially as one of those "desirable" herbs - alfalfa, a perennial legume / nitrogen fixer - grew everywhere on my plot.  However...  I quickly learned that a dense herbaceous layer=vole heaven, and voles=enemies of trees. This is my KEY issue, and the key objection to allowing rampancy of herbaceous plants in my case.

If these pests were not an issue, then yes, I would wholeheartedly embrace the strategy you describe, i.e., create a desirable herb layer around the trees, of the sort that doesn't compete excessively with the trees, and can be left unmown, or can be chopped and dropped from time to time.

Thanks for clarifying!

Tyler Ludens wrote:This may be a completely ignorant question - but how does temperate food forest herbaceous layer differ from subtropical herbaceous layer?  I see above in the thread people continually battling the herbaceous layer, whereas Geoff Lawton in his subtropical food forest, seems to welcome a particular kind of herbaceous layer which he terms "control through rampancy."  Is there not a way to replace the plastic layer with a desirable herbaceous layer?  Is the difference that the above examples are of a "permaculture orchard" and not a food forest, so there is no interest (or no need) for the different layers?

I think subtropical soils leech Nitrogen very quickly so it's really hard to build soil, add humus.

You can use some plants to replace plastic, it may depend on location and goal. I surround my fruit trees with comfrey which acts as a living mulch/fertilizer and suppresses weeds without competing with the tree for nutrients.

This is a pic of comfrey around an Apple tree.

hau Levente, We too have been having some vole problems that I have addressed with quite a bit of success. I went through several ideas before arriving at what is working.

What I did was purchase a quantity of "1/4 inch (5mm) galvanized wire mesh (over here we call it hardware cloth). The roll I bought wasn't very expensive and measured 50 feet long by 4 feet tall, I cut this into 2 foot tall by 50 feet long for ease of transport around the fruit trees and garden beds.
I dug 1 foot deep trenches and laid the wire mesh in then put the soil back in place. I went around each tree this way and around the perimeter of each of the garden beds (wet back for 3 more rolls of the mesh to get it all done).
So far, the voles have not penetrated my barriers (I found that they rarely dig down more than six inches, unlike moles which will go even deeper than two feet) I still see vole tracks (humped earth where they travel just below the surface) and those I stomp down every time I spot one. There are fewer vole tracks now than at the end of last summer. and non in any of the garden beds. The fruit trees are unharmed and no vole tracks are being seen around the trees (not since two weeks after installing the mesh barriers).

You might even try this trick on your swales, ( I haven't had any vole problems along my swales so far).

Redhawk

I too have had problems with moles puncturing my water-works. Around New Orleans, they have problems with nutria digging through the dikes that hold-back the Mississippi and ocean-surges! I've seen dogs (aussies and terriers) that can be trained to pretty effectively hunt moles/voles. Without animals, you will have to do the dirty work yourself (patrol/repair/trap). Unfortunately, you can't eliminate this type of animal completely and forever.

I've started to think of long berm-swales more along the lines of "leaky weirs".  Look up Peter Andrews on YouTube.  You can only do so much to hold/soak water before it eventually finds a way to escape; so do what you are able, then go with the flow when you have to ("those who can, do what they will; those who can't, do what they must")...

Good luck,
-B

Again I go back to a few hundred thousand snakes. More seriously though Levante, Sepp Holzer mentions an explicit strategy for voles in his gardening section, and for his hugel beds voles are a reason why he builds them slightly off contour to prevent landslides. Moreover, large pieces of wood embedded/anchored into the slope as they do in natural forests over time would allow a lot of seepage and storage during heavy rain/snowmelt but mitigate the amount of soil lost in any erosive event like a burrow. A nurselog never falls and stays on contour, it always rolls at least slightly off kilter. The wood also  provides predator habitat and slows down burrowers in my observation as my gophers and moles only touch the edges of my hugel beds.

I just went back and reread Sepp Holzer's Permaculture section on moles (p 182-183), and he emphasizes there is no point fighting voles. They simply reproduce faster to fill vacant territories, which coyotes and wolves will also do when hunted. They also eat a lot of rodents like foxes. Holzer even says he grows jerusalem artichokes and black salsify to provide the voles a preferred alternative to his trees. He also says that's why you need to plant a lot of trees.

About voles...in my experience, the pounding of machinery drives the voles to quieter places, which for you is the swales.  

You could repel the voles with a spray of castor oil.  Don't spray the trees, but around the trees.  Voles can't wash it off and it causes them intestinal discomfort without killing them.. so they'll go somewhere else.