Compact subsoils

[Jodgy]

Kia ora from Aotearoa New Zealand

I've recently purchased a 30 acre property on the Otago Peninsula - very close to Dunedin for those of you who know. A cool climate (we had snow three times last week), but one that is tempered due to the fact that we live right on the coast. Our land is on a headland. A beautiful, albeit often windy, place.

Previous land managment has been awful, to say the least. Thrashed is teh concept I often use. The soil has a poor structure and low fertility. There is NO shelter on the property. Luckily I'm young, so I Have lots of time to quietly tinker away and help this beautiful environment restore itself.

Anyway. . .at about 30-40 cm tehre is a relatively compact subsoil. It is not a hard hard pan, but will provide problems for tree roots trying to penetrate it. Any ideas - I've thought about ripping. I understand it is common practice in Aussie. Do you need to let the soil consolidate a bit prior to planting?? I assume you plant 10-15cm to one side of the rip.

Are there any species in Oz that are particularly well adapted to these hard soils?? They'll need to be salt tolerant as well.
We have some really good Eucalypt nurseries here, so probably can source many similar species.

Cheers

Jodg ???

[permaculture.biz]

Kia ora Jodg,

Sound's like a fun project - if you can get to use a keyline plow (or a gessner, agroplow etc.) then they have miraculous effects on the situation you are describing. Also detailed soil analysis is an obivous pointer.

You do need to allow some consolidation prior to planting trees - as you mentioned many of which could come from oz - also west coast US species.

Cheers,

DD

[Jeff Nugent]

My rule of thumb on deep ripping: Get the biggest dozer you can find with the deepest ripper and pull it on contour when the soil is at it's driest. This causes the pan to shatter. Plant into the rips in the second winter when the soil has consolidated. You can plant first year if you are prepared to go in with hand tools and prepare each planting space or have plenty of seedlings to spare.
I would question the use of eucs if you can avoid them. They are just too invasive and rob the soil, etc. I'm sure I said it on an earlier post.

[permaculture.biz]

Hello,

Something I have had a bit to do with is ground preparation for tree projects (as a designer/contractor) in a very wide range of conditions. What I have found 600 000 odd trees later is the better quality ground preparation the better quality resultant tree growth.

I started doing as Jeff suggested: getting a bulldozer to do the ripping. That phase of use didn't last long when I got my first keyline plow (a single beam 3 x 26" shank 3SB - which I've still got 10 years later), put it behind a 50hp Case tractor and ripped to 26" (single shank) using 10 litres of fuel per hour km after km after km (it seems like it will never end - particularly when you're doing soil renovation with the same machine. Later on in my contracting career we use a 75hp Deutz 4wd wizbang machine and three shanks at the same depth. A dozer on the other hand uses a lot more fuel and costs considerably more per hour to hire - dry or wet. The question of quality is poignant too. A dozer ripper point is angled such that anaerobic subsoils come up the face of the ripper - this situation is not ideal - similarly this ripper point angle helps rocks come to the surface as well from the deeper soil horizons. A yeoman's shank point is at 11 degrees which cleverly eliminates this from occuring, keeping the soil profile in place, at the same time as shattering the #### out of it - the timing of which I agree with Jeff - when its dry to get maximum effect.

In situation where you have rocks (particularly basaltic/granitic floaters) all over the place and shear pin breakage (@6 tonne break out force) on the keyline plow - well then you reach for the dozer with all its might. That is unless you have the latest yeomans with its hydraulic shank that flips up and rides over the rocks and then comes back down again without stopping (the dream machine).

The next part of the process is to cultivate over the rip line - using available devices such as (in order of quality and effectiveness): 1. Power harrow 2. Rotary Spader 3. Rotary Hoe 4. Disc plow 5. Chisel plow 6. Scarifier.

Then if the site requires it mounding with either (in order of quality and effectiveness): 1. Combination Power harrow/rotary hoe & bed former (we designed and built our own which works like a dream - see trees for some pictures) 2. Mounding discs (better in rocky conditions or sands.) 3. Horticultural bed formers/crowders

Following this process you can plant thousand of trees a day with less effort - you have at best market garden ground preparation from crap!

On the eucalypts front I agree with Jeff - steer away and go for multiple use higher value species (get a copy of his book @ Permaculture Plants of which there are many.

Enough for now I have to go into the lovely box iron bark forests and get some firewood.

Lovely day to you all,

Cheers,

DD

[spinifera]

been into multi level farming since I was a boy, but I live in texas, australia. it is hot here as well.
the deserts east of the southern coastal tip of texas are full of compacted soils. everything from hardpan on up.
there are two ways to approach this problem.
1. attempt to correct large areas of surface at one time to speed up the process. I believe the other replies have covered this well.
2. dynamite works wonderfully. this is no joke, if you can drill a bore hole just below the compact layer and set off the dynamite their. do this in a grid pattern across the land. plants trees at each point where you set off, and the roots will radiate through the fracture created in the explosion. these roots will then fracture the rest of the soil.

[permaculture.biz]

Go Gelignite Jack,

The mining game uses a similar technique to save on excavation costs - funny my old surveyor used to set out on the computer all of our tree layouts using a mine blast pattern - similar to the "array" function in AutoCAD. PA Yeomans also recommended the use of explosives in the repair of leaking dams - only he had the charge go off in the water not in the wall!!

Where appropriate this would work well - perhaps even better on a keyline layout....

Keep blasting....

Cheers,

DD