desertification

[drag]

Greetings !

I'm not certain the above name of the proccess
is correct. What I'm talking about is the
phenomenon that's occuring since the end
of the last ice age - more and more areas
are turning into deserts. I also believe
that the opposite also happened many times
(though I'm not certain).

My question is - how does it happen ?
What are the materials involved specificly ?
How can normal earth turn into sand and back ?
(Links will also be appreciated.)

Thanks !

Live long and prosper.

[iansmith]

From what I remember, desertification happen because sand is blown by wind into area were the vegetation is not dense i.e. no or few trees and mostly grass. I don't think the soil is converted to sand but sand is accumulating on soil. I think there is also leeching of nutriment due to lack of vegetation. So the soil get poor in nutriment, vegetation does is diying, and cycle recycle.

[RuroumiKenshin]

do you think that the "speed" of evolution could be determined, by finding out when a new creature arises after a drastic weather change occurs?

[The_oMeGa]

Desertification happens partially when the amount of evaporation exceeds the amount of condensation, which begins a drought. This happens partly bc of rising global temperatures. Furthermore, it can lead to hypertonically salinized (salty) soil, which can begin its harm by killing bacteria that convert nitrogen into usable forms, and later kill the plants themselves over time. Overgrazing reduces seed production because domestic animals eat the reproductive parts of the plant, and often eat the endosperm of the plant before it can grow. Exhaustion of soil by means of irresponsible ariculture and lack of irrigation can also contribute in desert formation.

[drag]

Thanks !
So, I understand it also works the same way
in reverse, right ?

[The_oMeGa]

hmm..i suppose you could say that