Ecological impact of soil amendments

 

 I always thought that what was local was best and cheaper.  I swear by
wood chips.   Marton NJ 20 miles away gave me green sand and I purchased
granite dust in the day.  Other things brought in was various manures if
I cleaned it up the coop or stall.
  Green manures are a given sort of like roots trying to help the soil.  
Dried blood and bone meal too.  (Prions)  I've also composted barber
hair and sea weed along with fish and game innards.

 Question ....are some amendments deleterious more than others?

 Peat got me questioning thinking.

--
Bill  S. Jersey USA zone 5 shade garden

 In places with high salt content in the soil already, soil amendments that
are high in salts can be bad news.  

    Una

 Una wrote:

I take it salt in soil is a sign of poor drainage and/or insufficient
rainfall.  When Rome finally took out Carthage they plowed salt into the
soil.  Carthage never came back from that and the place is still desert
today, but the soil is no longer salty.  Even in a desert there's been
enough rain and drainage to leach it all away centuries ago.

One of the long term problems with pumping well water and other
irrigation for crops is it tends to build minerals in the soil faster
than natural drainage.  The soil moves towards desert over a period of
centuries.  There are vast deserts in the world that were once lush
agricultural lands.  The desert of Iraq was one of the birthplaces of
agriculture and there was a History Channel show this week on a Sahara
site that was once a grain farming community.

 Una wrote:

In some places the salt is of geological origin:  former seabeds.  The
groundwater in some parts of the world is so heavily laden with salts
*from within the ground* that it is not drinkable and very few species
of plants can survive either.  It takes a *lot* of rainfall to remove
so much salt.

One cause of desertification is centuries of extraction of organic
matter, and soil nitrogen, by humans.  Intense agriculture does that,
where biomass is produced in one place and consumed somewhere else.

    Una

 Doug Freyburger wrote:

Not necessarily, it is a complex issue with more than one cause, see:

http://en.wikipedia.org/wiki/Soil_salination

When Rome finally took out Carthage they plowed salt into

Yes rainfall will tend to remove salt just as it leaches all soluble salts
over time. It isn't clear to me if the proverbial application of salt by
Rome resulted in the desert, I suspect there is more to it than that.


That can happen but it is not the only way that soil damage can be caused.
Irrigation water can raise the water table so that salty water that was
safely buried comes up to interfere with plant growth

The soil moves towards desert over a period of

I wouldn't assume that all that was all due to salinity, over grazing and
other mismanagement contributed.  It is much easier to damage soil and allow
deserts to encroach than the reverse.

See:

http://en.wikipedia.org/wiki/Desertification

 I seem to recall that there have been some climate change effects in the
fertile crescent too (over millenia not the last century) but I cannot find
the reference to it.

David