[svenrufus]

'scuse me if this has been done before, but I don't understand what I am being told.

At my allotment site, the council dumps stacks of woodchips, which are free to use. I'm doing some of the paths as does everyone else. but I also want to add some to the soil as in places it appears to have virtually no organic content, and with such a limitless supply of it, I figured the woodchips were a good way to go.

But. I keep getting told that it removes the nitrogen from soil if added like I am. I don;t understand that - where does it go? Even if somehow it uses it for a bit in decomposing, surely it is still there at the end of the process?

Is it just the decomposition that is the problem - ie if I allow it to rot down before adding it, will it then be OK?

Or is it all a bit of an urban(/rural) myth?

Cheers
Sven

[5thhorseman]

Apparently it removes nitrogen from the soil due to the decomposition process, but once it's rotten the nitrogen is returned.  So I suppose it's best if you let it decompose first.

I also read something about the process making the soil more acidic, so it might be okay for some plants, but I haven't got to the bottom of that yet.

I wouldn't mind hearing another answer on this as I also have lots of wood chips and sawdust and am hesitating even to spread them on top of the soil (might help prevent slugs).

[harrymac]

It's true that adding wood chips to soil will cause nitrogen to be depleted from the soil.

The bacteria that cause decomposition need a balance of carbon to nitrogen (something in the region of 30:1 C:N). Wood is high in C and low in N, so to get their balanced diet they take the nitrogen from the soil.

The wood chips can be composted, but it can take years. The process will be speeded up if you mix in plenty of 'greens' - nitrogen-rich material such as green leaves (though not from trees), grass cuttings or poultry manure. The bonus is that when it does decompose you'll have a high quality compost.

[celjaci]

Good points mentioned above.

Do you have space to stack it for a season or two? It could be used when well rotted.

Time to rot depends on what the material is like - real wood chip from large branches will take a really long time to rot, thinner, twiggy stuff with leaves will rot a lot faster.

As mentioned the decomposition process can be speeded up by adding nitrogen, dried blood or BF&B can be added or maybe you could set up a urinal? French style pissoir for visitors?