Humus turf in cold climate to humus rich soil?

Everyone knows the humus turfs in colder climates with sand beneath it, called podsole. Sometimes these organic layers are up to 30 cm thick. So building humus in colder climates is not that big of a problem, water is the limiting factor.

How can I improve this type of soil for better water holding capacity?

I have a small island in Finland and already started to decrease the acidity level by cutting conifers and letting leafy trees grow unhindered.

Any ideas/suggestions? Every kind of input is welcome.

Have you considered biochar ?

Biochar is not an option for me but thanks for the input. I want to improve the soil with as low cost as possible.

I thought about Hügelkultur though. Cutting some more conifers and letting them rot in a shady moist place for a couple of years. Any other ideas?

I would also love to know about podsol in general or in depth, e.g. the particular mineral deficites they have. I read podsole is always low on calcium one of the most important minerals at all, am I right?

I don't know much (or anything) about podsole, but if you're on an island, chances are good you've got access to kelp, algae, or seaweed.  applying those directly to your land or sending them through critters first can be good ways to get some minerals back in the dirt.

and if you've got 30 cm of organic material already, you're in pretty good shape to begin with.  I'm not suggesting you wouldn't want to improve it further, of course.

where in Finland?  is this a lake or sea island?

Are you able to get your soil tested? That would be the best way to see which minerals are missing. If calcium is low, you could try plants that accumulate calcium (dynamic accumulators). The following plants take up calcium and store it in their leaves:
German Chamomile (C. nobile) (also accumulates K and P)
Silverweed (P. anserina) also accumulates K and Cu
Comfrey (Symphytum spp.) (one of the best, accumulates Ca, K, P, Cu, Fe, Mg
Nettle (U. dioica) (Ca, K, S, Cu, Fe, Na)
(info from Edible Forest Gardens by Dave Jacke)

when the plants die down for the winter, or you cut them back as mulch, you keep the calcium cycling through your soil. Holding the calcium in plant tissue prevents it from leaching out of the soil. If you want an all purpose plant to keep fertility high, comfrey is my choice, but do your research, as it is dispersive and opportunistic. The russian comfrey has been reported to be less feisty.
Best of luck!

Thanks for your answers!

tel jetson, it is an island near Savonlinna. A lake island. I read about algal limestone but I don't understand its use yet. Bringing in biomatter won't hurt but it won't help either. I read that this "duff" (this layer of unprocessed biomatter; found the scientific correct word for it) occurs because of bad environmental conditions.

Duff is hydrophobic but water is essential for microbes and macroorganisms to process biomatter. One solution might be adding clay and calzium to the soil. But without proper microbial activity it won't work to built lime-clay-humus-complex. Are you all familiar with lime-clay-humus-complex? (Don't know the english word to describe that stuff)

I introduced locally common species on the island two years ago. Beside from plants I introduced local earthworms and not-so-local "rough woodlouses" from Germany. There weren't any! Can you imagine this? No earthworms, no rough woodlouses. There is clearly a microbial and macrobial decomposer deficiency on this island.

Lydia S.: Thanks for the list! I tried to introduce comfrey and lupins two years ago but failed miserably. I didn't know about the hydrophobic propertiers of duff back then. Next summer when I visit the island I will make some seeds balls and introduce the species listed by you there.

PS: I already introduced one nettle species. I don't know which one it is but it is doing okay there. It is green with white stripes.

Sounds like you have quite a challenge on your hands!

How large of an area is affected by the hydrophobic soil? If it is not too big, you might want to try sheet mulching right over it and planting it with a cover crop. It will take a few seasons, but mulch will most likely improve the soil quality and ability to hold water. Try to mulch with what is already growing there so that you don't have to transport the mulch.

Also, I think that podsol better characterizes the soil you describe, "duff" is a general term: from dictionary.com:

duff
–noun
1.
organic matter in various stages of decomposition on the floor of the forest.
2.
fine, dry coal, esp. anthracite.

Best of luck! Let us know what you find out in your research!

No, Duff fits the description perfectly right. There is a layer of unprocessed biomatter on top of nutrient poor sand and rock. Duff describes it perfectly well because there is no REAL soil or dirt. I got this sand stuff tested two years ago but I don't have the sheet at hand.

The area affected is approximatly 2 hectares big - the whole island. The island is formed like a boomerang. On both the cone ends are hills with a valley in between. On the hills grow mainly pinetrees. The valley is mainly occupied by elders, birches and aspen. The valley is maybe 30-50 cm above water table and there are also lots of unprocessed leaves on the ground. Same problem here. Microbial deficiency.

I love challenges!

I introduced some cherry trees with their tap root they shouldn't have problems getting water and minerals because there is a calzium horizon when you dig deep enough where all the washed out minerals are located. You have to dig maybe one meter deep.

I think I understand what you mean, it's really interesting-Try mulching in the areas you are currently planting trees and perennials--that will help the decomposition process along and hold in moisture in the layer of unprocessed biomatter.
Definitely keep us posted on how the cherry trees and plants are doing, best of luck!

That is quite a land you live in!  Its hard to tell if there is more lake or dry ground. 

"Because no set definition of what constitutes a lake and no procedures for counting the number of lakes exist, it has been impossible to ascertain exactly how many lakes the region has. There are, however, at least 55,000 lakes that are 200 or more meters wide." - WIkipedia

Long cold winters as well I suspect.  61 N latitude, 25 inches of rain spread throughout the year...

The english spelling is "Spodosol"...

Spodosols are acid soils characterized by a subsurface accumulation of humus that is complexed with Al and Fe. These photogenic soils typically form in coarse-textured parent material and have a light-colored E horizon overlying a reddish-brown spodic horizon. The process that forms these horizons is known as podzolization.

Spodosols often occur under coniferous forest in cool, moist climates. Globally, they occupy ~4% of the ice-free land area. In the US, they occupy ~3.5% of the land area.

Many Spodosols support forest. Because they are naturally infertile, Spodosols require additions of lime in order to be productive agriculturally.

Spodosols are divided into 5 suborders: Aquods, Gelods, Cryods, Humods, and Orthods. Click here for more information about these suborders. Click here to view a map of their distribution in the US.

So it sounds like intense leaching, and the loss of Ca and other bsaes... likely Mg, K.  The soils are sandy and thus have poor nutrient holding capacity to start with.  So heavy lime and organic matter.  You are also managing with a very short growing season.

Formed mostly of underlying sandy parent materials, spodosols tend to be strongly leached, with low fertility and limited water storage capacity. Many areas where these soils occur have not been cleared of trees for farming. Large tracts of spodosol border the tundras of North America and Eurasia. Characteristic of these soils are subsurface horizons in which amorphous materials composed of organic matter, aluminum, and iron have accumulated. The heavy application of fertilizers and lime has enabled cultivation of grains, potatoes, berries, and silage corn (maize) on spodosol soils in the cool climate of the north-central United States.

The recommendation for oceanic nutrients makes a lot of sense... I bet for most 'western foods' you will be manually creating patches of fertile soil.  Forest plants maybe... ferns, nettles.  Calcium shortage may explain your shortage of arthopods.  Calcium accumulators for mulching might be useful once you import calcium to keep it cycling.

This is all guess-work.  How does your traditional indigenous culture make a living? (I always think Reindeer when I think of your lands).

I only want to grow perennials anyway. I'm only one month in summer time there (the whole finnish summer to be precise )

Lime was already tried over a period 5 years by my mother but without clay it can't work.

I think I have plan though: I already made some terraces. I will dig these out, put some rotting wood in, mix the sand with clay, compost, algal lime and this duff stuff. Then introduce a variety of mineral mining plants with seedballs. Maybe it will form at least some lime-humus-clay-complexes to built upon. When it does water retaining capabilities should be improved and in the process help sustaining microbial live in the soil.

The locals have (moderately) fertile land at their hands. Some islands formed basins in the middle where the nutrients and table water meet. There agriculture is not a problem.

I wonder if due to your short growing season and leaching it might make sense to process some organic matter in a more bacterially rich environment.  worm boxes in a protected locations (buried?) where you attempt to produce more stable humus (worm castings) to import into your beds each spring.  I could imagine every summer focussing on a single bed and burying all your food waste while you on the island, to build up a worm population, and move to a neighboring location next year.

In addition to the wood, since you are selecting for deciduous trees, importing fallen leaves into your bed might be good as well... the trees may do the best job of mining cations.  The deciduous leaves will be a relatively rich local source.

I seem to remember that in podzolization some of the leaching happens as snow melt picks up acid from the duff which washes through the dormant sandy soil. 

Do report on how it all works!

Worm boxes are great idea. Worm towers are even a better one. We always have guests on the island and we easily fill one compost bin in one month. I bet we could fill 4-5 worm towers instead. We have no problems geting our hands on cow and horse manure, as there are many farmers and one horse race stable around us. We could dilute our food scraps and fill 10 or 15 worm towers. When they are in a distance of 1 meter to each other we could transform 10-15 squaremeters per year in that fashion. The gaps between would be heavily mulched, clay, lime and mining plant seedballs added. In the following years we could plant berries and fruit trees on that location.

One of my goals is to establish a birds paradise on the island. I love birds and they are great to manure the landscape when you can't have goats, horses or other big animals. Most of the perennials I plan to plant are thorn- and berrie hedges and specific tree species for bird habitat and as a food source.

I already support insects by creating habitats for them. Hanging up wood slices at dry places, in which I drilled holes, has proved to be the best way to support them. Birds love those insects.

Yeah, snow (+ acidity of the needles) is a big problem. I already started cutting pine trees but it will take years for the acidity to be neutralized. I hope I can speed things up by gently helping mother nature with it.

Just wanted to give you a short update:

Last year I wasn't visiting Finland at all because my mother had a stroke. This year I was only for 10 days there. The perennials are doing fine and grass is taking over. I mowed a little bit here and there and threw in some clover seeds. Nothing dramatic. Minor repairs, cleaning the houses and roofs where more important. The terraces and perennials I planted there are doing fine - they are not dead yet anyway! Even though I never came by to put rotten wood in there. I left some big piles of brush and logs there 2 years ago and I will use them hopefully next year to get everything done as planned.

Damn, it is a shame I couldn't stay there longer - the island is soooo beautiful!