Message Board - Natural Turf: why does "black layer" form a layer?
12 Feb 2010 by Chalky 1
If this does not sound like a dumb question I was wondering why the black layer does indeed form a layer?
I understand it is an indicator of anaerobic conditions but if that is so why is not all the soil below the maximum extent of the air penetration black if the same conditions exist?
To put it another way if my soil is anaerobic at two inches I assume it must be anaerobic at three and four inches as well, but often the black is only a thin horizontal line at one shallower depth.
I am wondering if in fact it is the anaerobic/aerobic interface in the soil I am looking at and that perhaps some air is crucial for the production of the most pronounced black layer?
I'll admit the inspiration for this hypothesis comes from reading a bit in a book about the sulphur respiring bugs that live around the volcanic vents on the sea floor still having a dependance for some oxygen on the photosynthetic bugs that live up in the ocean waves so I accept I might be way off with this idea.
Anyway I'm sure someone knows the answer so if they would be kind enough to enlighten me.
And being mindful of recent posts I offer my thanks in advance, my internet access is patchy at the moment and it could be a week or so before I get back to this one.
Cheers
Chalky
13 Feb 2010 by Anthony Asquith Last edited 13 Feb 2010
Hi
Hydrogen Sulphide is very toxic to plants and is equaly reactive with soil metals (ex Fe, Mg) and this reaction precipitates as metalic sulphides. These sulphides block pore spaces. Iron for example (Fe) in the Oxide form, set like concrete and seals the surface, particulary prelevent in soils that do not drain too well. Chemicaly, it is the deposit of metal Oxides, formed during reduction of S compounds in low oxygen conditions. Elemental S (Sulphur) is generaly oxidised to Sulphate in soil, so in a sense, it 'removes' Oxygen, but there is usualy plenty of Oxygen around, the latter is all about electron doners and acceptors.
Cheers
AA
13 Feb 2010 by Steve63
Don't talk to me about Contractors Wonka, I am one myself......
13 Feb 2010 by Steve63
http://www.scottsproseed.eu/img/EU/iturf/iTURF_Black%20Layer.pdf
Don't talk to me about Contractors Wonka, I am one myself......
13 Feb 2010 by Steve63
http://grounds-mag.com/mag/grounds_maintenance_irrigating_layered_soils/
Don't talk to me about Contractors Wonka, I am one myself......
15 Feb 2010 by williams1
http://www.gcsaa.org/gcm/2001/dec01/12blacklayer2.html
Back to Top - Go to Next Unread Message
This Message is closed, you may not post a reply at this time
