http://webcache.googleusercontent.com/search?q=cache:mP_UMOO8oZwJ:www.public.iastate.edu/~jasandor/Human%2520Impacts%2520on%2520Soil%2520Formation%2520Final.doc+&cd=1&hl=en&ct=clnk&gl=sa

In the span of a human generation, fire can, in theory, impact all the land covered by vegetation. Its occurrence has many important direct and indirect effects on soil, some of which are long-lasting or even permanent. As a consequence, fire must be considered a soil-forming factor, on par with the others traditionally recognized, namely: parent material, topography, time, climate, living beings not endowed with the power of reason, and humansEarth has been rightly defined an “intrinsically flammable planet” , although Earth’s flammability is confined where both fuel and oxygen are available, hence to about 110 millions km2 of vegetated land, representing less than 22 % of Earth’s surface . Global burned area per year clusters around 3.5 millions km2  i.e., 3.2 % of the “combustible” land. Assuming that every year fire involves different areas, it means that cumulatively all of the vegetated land is burned in about 31 years, something more than a single human generation! In reality, wildfires often run on ecosystems particularly prone to burn, while other ecosystems seldom burn. Where fire is frequent it is a driving force for the takeover of land by fire-adapted plant communities. The global impact of fire on vegetation is so marked that in a hypothetic world without such an ecological factor, closed forests would be double than the present ones .

Without doubt, it will.it already has.

I concur with EVM that man has become the greatest influence on soil genesis. 

I appreciate the comments of colleagues who responded.We all knowJenney's equestion on soil formation,s = f(cl,o,r,p,t,...).Human/man is not only a sixth factor,but also influencing the other factors like climate,organisms(both vegetation and animals apart from microbes) and relief.He may be interfering /influencing time factor also by accelerating the process of soil formation and soil loss/degradation.Even he is exposing the parent material for the other factors to act upon.For the sake of humanity ,man/human should not interfere much with the factors of soil formation.We all should pay great attention to soil loss by erosion,single largest threat to our survival on planet earth.

thank you. I absolutely agree with Dr. Subba Rao

Confirm. Plaggic Anthroposols are common around my German village. 

I am going to suggest another kind of Anthroposol created by domesticated grazing animals that is changing geologic history, as they have here in California.

 In less than 100 years, we caused the extinction of the perennial native grasses that were soil-forming, and we are left with European annual grasses that help the grazing animals steal the soil nutrients, and do no soil formation.  

If we look at geologic layers in California, we see tens of thousands of years of layers put down by the perennial grasses and 5,000 kinds of wildflowers, then about 1850-1880,  the new exotic plant-sourced Anthroposols start getting laid down.  

If you look at the photos of the planet from http://www.confluence.org you can see that wherever humans can grow crops or graze domesticated animals, we have radically changed the native plant communities, so that future geologic layers will be guaranteed to be Anthroposols?

Dr.Craig,nicely illustrated/narrated example.Humans are occupying and changing the landscape altering all natural processes.How to preserve the natural landscapes/forest reserves in developing countries with high population is big question.

We have entered the biological Dark Ages, and like the people who preserved the written knowledge during the European Dark Ages, maybe the best that we can do for the rest of the 21st century, is to make sure that we have numerous refugia?

These would be areas where the local native ecosystems can survive our ecological hurricane that we have unleashed on the planet, that the local people are paid to preserve and restore the areas, instead of exploit them?  

You can see the geologic change in the soils caused by domesticated animal grazing in the Southwestern USA from the paired photos of Dr. Robert Humprey at http://www.ecoseeds.com/desertgrass.html.

Take any country that has a lot of images on the http://www.confluence,org and take a on-the-ground vegetation trip, and see where we have wasted trillions of dollars by the world's countries on investments in militaries and wars, or supporting criminal bankers, instead of using all that money over the last 10, 50 or 100 years on the upkeep and fixing the life-support systems of the planet?

http://www.confluence.org is the proper link, a real eye-opener when you look at the pictures from an ecological and native vegetation perspective.  Makes me want to go visit the unvisited confluences and see what is still there?

http://www.confluence.org

Wanted to add two more aspects to this soil issue question, that everyone can try at home.

1.)  Spatial extinction of the native understory.  Areas like California, Arabia and North Africa are some of the most severe examples of spatial extinction of the native plant understory, caused by animal grazing.

And without the native plant cover, you have stopped the soil-building that those plants did for centuries.  Using the northern California grasslands, the Mojave and Arabia deserts as examples, I did three paintings No. 61, 62 and 63 about what has happened at http://www.ecoseeds.com/art4.html.

Each painting's color represents a native plant family, like the grasses, etc., and the width represents percentage cover that existed at various times in the past. Of course in 2016 the answer is close to zero, but each painting also shows a future where we might start the process of ecological restoration.  

Each country could do a similar painting, showing the understory of native cover over time, and estimate its overall percentage cover today, and mark the changes over time.  I am not painting the trees or shrubs, just everything covering the ground underneath, like the grasses and other natives, wildflowers, etc.

2.) Soil nutrient changes from grazing animals.  Another painting at http:://www.ecoseeds.com/art4.html, painting No. 60 shows what only 200 years of cattle grazing did to our soils, to drop key soil nutrients below what the native seedlings need for survival.  

This process of "soil nutrient robbing by domesticated animals" has probably happened to soils in about a billion arid acres of the planet, and is often overlooked by researchers trying to get local native plants to grow in barren areas or to replace stands of exotics.

You can find these soil conditions through three different experiments--

(A.) GOOD vs BAD. Test the top 5 cm. of soil around a reproducing population of native plants, then within a few meters where they do not grow, or from a nearby population that is not reproducing. Get all the major nutrients N-P-K-Ca-Mg plus all of the minors, Mn, B, Cu, Zn,etc.  

(B.) ADD NUTRIENTS UNTIL GOOD. Take the top 5 cm of soil and place it in a container and sow native seeds in one and see if the seedlings survive or not.  If not, add nutrients until you get seedling survival.  Use the photos from Howard Sprague's book "Hunger Signs in Crops" (2nd or 3rd edition, out of print) to use the leaf colors to indicate what missing nutrients need to be added.

(C.) EACH SPECIES HAS ITS OWN THRESHOLD. Remember that every native species has its own soil nutrient minimum seedling survival threshold, so what might work for a native annual grass species, may not work for a member of the sunflower family for example.  

And then within plant families, like the grasses, there is going to be wide ranges between species. You will need to check several dozen different native species, and also check the local weeds for their threshold values.

WEEDS GROWING IN SOILS TOO POOR FOR THE NATIVES? You will probably find that a lot of grassland weeds in particular, are "default" weeds, in that they mostly grow in soils where the grazing animals have removed the nutrients below the levels needed by native seedling survival.  That is what my painting is about, the weeds come in at a particular low level, and the natives need a higher threshold level to survive.

You can see a picture of one of my first tests of this soil-nutrient-threshold idea at http://www.ecoseeds.com/good.example.html

http://www.ecoseeds.com/art4.html

http://www.ecoseeds.com/good.example.html

I compliment Dr.( Ms.) Nikou for the good question and I really appreciate the  very  informative responses of Dr.Craig.

Dr.Craig,your attachments are eye- openers and everybody should visit/see them to really appreciate the need for nature conservation to the extent possible in every country.

I am posting two photos I took today of one of my Ecological Restoration projects, where I sowed local native grass seeds, after doing the soil tests and adding the missing nutrients and that first photo looks like a nice green pasture.  

The second photo is where same seeds were sown in an unfertilized area nearby, and the seeds sprouted, and are now dying from starvation, when only a few cm. tall.

This is the result of soil nutrients stripped out of the soil after only 200 years of grazing in California!  

So the question might be, what are the results where domesticated animals have been grazing a country for a thousand years or 2,000 years, or 5,000 years?

Even if we wanted the local native plants to grow back, in many hundreds of millions of hectares of our planet, they would not be able to do so, until we fix the soil nutrients and raise them to local native seedling survival thresholds.

agricultural activities especially in steep slopes also have increased the rate of erosion and soil nutrient depletion in a fast speed in Iran.

California and Iran are botanically and by our land use, very similar.  We each have over 5,000 native plants that are being impacted by grazing that is occurring over a lot of your country, according to the Land Use map at http://images.nationmaster.com/images/motw/atlas_middle_east/iran_land.jpg

Iran has wastelands and rough nomadic herding areas, plus regular pastures that make up maybe 80% of the country?  Then there are the farm lands and the woodlands that make up the remaining 20%.  

INTERFACES. It would be very interesting to go to the woodland-rough grazing interface, and see what is happening to the soils.  Or the wasteland-rough grazing interface, what are the soil conditions that are creating wastelands, is it the lack of one nutrient that is tipping the balance?

CONFLUENCES. Also, only 47 or the 171 confluences have been visited and photographed for Iran, so it would be good for someone to get a grant and complete those confluences, and at the same time do a vegetation and soil survey of the country at that time.  I have attached the photo from Lat 37N Long 55E.

I have put together several vegetation megatransects using the Confluence photos that are indexed at http://www.ecoseeds.com/mega.html.

SOIL REPAIR. We are always spending money "defending" ourselves investing on our militaries, instead of looking to fix the leaky life raft of our soil conditions that everyone on the planet depends on for their survival?

SELL CARBON CREDITS. For example, it might be better to pay the pastoral people to restore the grasslands and sell the soil carbon as carbon credits to Germany and Japan, rather than continue to mine the soil nutrients via the grazing animals, and also invest to return the nutrients needed by the native plants?

http://images.nationmaster.com/images/motw/atlas_middle_east/iran_land.jpg

http://www.confluence.org/country.php?id=112