I used wood chip on my garden and the roots of my plants we eaten by wood lice .There was a huge number of wood lice and they ate everything I then dug the mulch in and I now know why I couldn't grow anything there for some years It had obviously depleted the nitrogen Unless you want a sterile area for paths may be I would not use wood chip
Woodlice are detritivores which eat dead and rotting plant material. Something else ate your plant roots before the woodlice, the worst offender is often vine weevil grubs.
My understanding of the research is that there is a small but temporary depletion of nitrogen as the woodchip in contact with the soil breaks down via the actions of microorganisms/fungi but once it’s broken down it actually returns slightly more nitrogen to the soil than it originally depleted.
If you top up the woodchip mulch annually, the new layer is rarely in contact with the soil as there is still some residual undecomposed material at the top of the previous layer acting as a buffer, so even the small initial soil depletion is not repeated. My conclusion is that the benefit of woodchip mulch in adding organic matter to the soil, acting as a weed suppressant, moisture retention etc., by far outweighs an initial, temporary and insignificant loss of nitrogen that established plants would barely notice.
There may be some legitimate concern about vulnerable new plants, where a temporary loss of nitrogen could be more significant, but the application of a small amount of fertiliser high in nitrogen such as chicken manure or a nettle tea would compensate more than adequately in their first year. But I would want to see physical signs of deficiency before doing that because overdosing on added nitrogen could kill rather than cure!
Mountainous Northern Catalunya, Spain. Hot summers, cold winters.
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I live in west central Scotland - not where that photo is...
If you top up the woodchip mulch annually, the new layer is rarely in contact with the soil as there is still some residual undecomposed material at the top of the previous layer acting as a buffer, so even the small initial soil depletion is not repeated. My conclusion is that the benefit of woodchip mulch in adding organic matter to the soil, acting as a weed suppressant, moisture retention etc., by far outweighs an initial, temporary and insignificant loss of nitrogen that established plants would barely notice.
There may be some legitimate concern about vulnerable new plants, where a temporary loss of nitrogen could be more significant, but the application of a small amount of fertiliser high in nitrogen such as chicken manure or a nettle tea would compensate more than adequately in their first year. But I would want to see physical signs of deficiency before doing that because overdosing on added nitrogen could kill rather than cure!
I live in west central Scotland - not where that photo is...