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Topsoil depletion, how long can we keep it up?
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Author:  Dingo [ Sun May 03, 2015 7:01 am ]
Post subject:  Topsoil depletion, how long can we keep it up?

I know there is a school of thinking that says we can manage growing more and more food on a fraction of what we presently use, given high intensity agua-culture(Farmed fish for instance), vertical greenhouses, nourishing concentrated algae goo, munchable fungus, not to mention high protein insects, grubs and worms and such. Still I think farms with their accompanying topsoil will remain our principal source of food.

With that in mind its rapid erosion should be a matter of concern along with the accompanying problem of increasing population. Here is a general look at the matter....

http://npg.org/library/forum-series/foo ... ntury.html

...along with a more extensive linked paper on the matter.

http://www.npg.org/wp-content/uploads/2 ... ury-FP.pdf

NPG also offers a mind boggling rundown, state by state, on many matters accompanying population growth including the steady loss of topsoil. This is definitely a find.

http://npg.org/library/population-data.html

Finally in the strange world of cognitive dissonance George Monbiot weighs in eloquently on the topsoil issue, ignoring curiously that in the past he has declared concern with overpopulation is little more than the rich wasteful resource users deflecting into poor bashing.

http://www.monbiot.com/2015/03/25/3703/

Author:  herlbert [ Mon May 04, 2015 4:54 am ]
Post subject:  Re: Topsoil depletion, how long can we keep it up?

I think overpopulation could be one factor but, not the root cause of loss of top soil. Rather the people who know the issue and aware about the issue but choose to do nothing.

Author:  Wayne Stollings [ Mon May 04, 2015 5:48 am ]
Post subject:  Re: Topsoil depletion, how long can we keep it up?

Since we are depleteing aquafers and losing the natural reserves of water in moubtain glaciers, there may be a race as to which of the necessary ingredients will go first.

Author:  Dingo [ Mon May 04, 2015 12:28 pm ]
Post subject:  Re: Topsoil depletion, how long can we keep it up?

herlbert wrote:
I think overpopulation could be one factor but, not the root cause of loss of top soil. Rather the people who know the issue and aware about the issue but choose to do nothing.

The problem is overpopulation commonly is associated with the desperation to get a quick return over more long term sustainable approaches. Slash and burn in rainforests would be one example.

Author:  Johhny Electriglide [ Tue May 05, 2015 12:32 pm ]
Post subject:  Re: Topsoil depletion, how long can we keep it up?

In the past 100 years we have lost 2/3 of our farmland topsoil from a variety of reasons; erosion, micronutrient depletion, sterilization, salinization from river water irrigation, waterlogging from too much, citification, heavy metal pollution from petrochemical fertilizers with diminished returns, with over fertilization leading to estuary dead zones. At that rate of loss the Earth will only have pockets of good soil left IF we make it 2140. That is from research done in 1995, and nothing has changed with the rate of depletion.
Then there is the draining of long term regenerated aquifers and capped no recharge aquifers. The San Joaquin, Columbia, and the once great Ogallala will be gone before 2040, with extreme reduction in yields from their loss, typical around the world.
Then we have the loss of crops in one out of every three years from climate fluctuation beyond historic by then.
The intensive agriculture to feed overpopulation also produces 30% of HGHGs, so with the necessary 90% reduction to stop continued runaway, all farming must be local. No more distribution by diesel, or huge tractors and combines.
Right now northern China and India have large areas of sterilized soils only holding up crops nourished incompletely by petro-chemicals. Completely devoid of organics. Other smaller areas have the problem also, like Idaho.
Then, there is still increasing demands from overpopulation getting worse and people wanting a better diet. What most are getting is not a better diet but one with more and more additives that, with water pollutants, is driving the 30% obesity epidemic worldwide. Changes like corn bigger than rice now in China, are bringing even more intensive petrochemicals and water use.
It all leads to less food on average per capita to below sedentary starvation level average, conflicts over water and food scarcity, and crashing, migrating populations desperate to escape to where there is more food and water and less or no warfare. They overload the economies of the host nations driving economic depression, which continues the crash from mass starvation.
It is unfortunate that 2040 comes after crossing the tipping point of tundra methane releases rapidly increasing temperature beyond the worst case scenarios of most. So those survivors will have a more and more difficult time surviving until the surface is too hot for most species to survive, and what organics are left in the world's soils release their CO2.
Certainly not a good way to treat your home planet's biosphere, of which the soil is an integral part.

Author:  Johhny Electriglide [ Sun May 17, 2015 2:58 pm ]
Post subject:  Re: Topsoil depletion, how long can we keep it up?

Part of soil depletion;
"Soil helps regulate the carbon and water cycles — it’s a reservoir for both cycles, buffering them from shocks and feeding us, all at the same time. But, Amundson et al. warn:


Profound changes are on the horizon for these interconnected functions — particularly sparked by changes to climate and food production — that will likely reverberate through society this century. Ultimately, the way in which we directly and indirectly manage our planet’s soil will be interwoven within our future success as a species.

We are already running into a hard limit when it comes to soil nutrients. Plants need nutrients like phosphorus, nitrogen, and potassium to grow. Microbes, certain plants, and human factories can pull nitrogen out of the air (there’s plenty of it in the atmosphere), but the other nutrients have to come either from mining or recycling.
For a lot of reasons (contamination with prescription drugs, heavy metals, and pathogens in the sewage system) people dislike the idea of turning municipal sewage into fertilizer.
Those flushed nutrients never leave the system in the largest sense, of course: They end up in lakes and oceans and landfills. Phosphorus in the ocean can turn into an algal bloom, which turns into fish, which birds eat and poop out, which we mine for fertilizer. But that cycle takes place far too slowly to meet the needs of hungry humanity.

The only other option is to mine those nutrients, and we are running out:

The growing demand for P [phosphorus] has recently caused an increase in the cost of rock phosphate from about $80 per U.S. ton in 1961 to up to $450 per ton in 2008. Prices since then have fluctuated but are now at about $700 per ton … K [potassium] prices were ~$875 per metric ton in 2009 yet are expected to reach $1500 by 2020.

And the authors point out that these elements are unevenly distributed. The biggest phosphorus mine in the U.S. will be depleted in 20 years, and geopolitical balance of power may get shaken up as nations and corporations begin competing for the remaining reserves in places like Morocco. Oil wars are one thing; at least you can replace oil with other forms of energy. But it’s physically impossible to replace a basic element like P or K."
http://grist.org/food/the-next-big-war- ... gn=climate

Author:  Johhny Electriglide [ Mon Jun 22, 2015 12:37 pm ]
Post subject:  Re: Topsoil depletion, how long can we keep it up?

^^^^^^^^^^^^^^

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