Re: Seaweed'n'Salinity

Tim Longville wrote:
> 
> Susan - re your query -
> 
> the only thing that I have wondered is whether the salt on the seaweed
> 
> impacts on soil salinity levels? (a major prob for Aust soils) I have
> been
> told that it doesn't, but still not entirely sure? Any info?
> 
> All I can say is that in UK conditions this doesn't seem to be a
> problem. Like Dave Poole, I just bung it on, have done for years, and
> have never noticed any adverse effects. Indeed, very much the reverse.
> On the other hand, our soils aren't your soils and, perhaps just as
> importantly, our rainfall isn't your rainfall! Here, the seaweed tends
> to get vigorously and repeatedly washed as soon as it hits the beds -
> not by me but by the heavens. That's a (minor) reason for putting it
> on in our autumn, which is a maximum period for rain in our anyway
> rainy climate.
> 
> If you have a particularly saline soil to begin with then I dare say
> more care would be needed but you really need an Aussie correspondent
> to provide the local facts. My own feeling would be that if I had to
> go through a rigorous washing and re-washing programme before I could
> use the stuff, I probably wouldn't bother, since its great advantages
> are that it's readily available and equally readily usable.
> 
Tim
I think the key point in this is the rainfall and probably also the
temperature. Where rain falls reliably throughout the year and summer
temperatures are essentially moderate there doesn't seem to be any
noticeable build up of salts, but in low rainfall-high-temperature
climates evaporation may prevent there being sufficient moisture to wash
salts down through the soil.

What springs to mind is the Mesapotamian region which in very early
times, although virtually without rainfall, had highly fertile land
beside its rivers due to extensive irrigation. However, although the
water used was officially fresh, not salt, there was a sufficient load
of salts in it to accumulate in the topsoil as a result of the very high
evaporation rate..

After a long period of time the land became so salty most of it could no
longer sustain crops and had to be abandoned

One might have expected a similar state of affairs to develop in 
ancient Egypt, but I think the regular annual flooding of the Nile must
have been sufficient to clear away excess salts and prevent it
happening. What happens these days with that high dam in place I don't
like to think.

Moira
-- 
Tony & Moira Ryan <theryans@xtra.co.nz>
Wainuiomata, 
New Zealand (astride the "Ring of Fire" in the SW Pacific).
Other Mailing lists | Author Index | Date Index | Subject Index | Thread Index