Dear Muhammed,

I do not agree that sandy soil are the main soils in arid environement. First of all what is a sandy soil for you, an Arenosol (WRB classification)? Or a soil where sand is the main particle size (granulometry)?

If you speak of Arenosol, yes you find them in Sahara but there are also widely areas where only hard rock is find (Leptosol) or other superficial soil less sandy , stony (Regosol)

Indeed, in arid environement, you will find also a lot of soil where salt or carbonates precipitates (Calcisol) or salt (Gypsisol, Solonchaks or Solonetz).

To conclude, I will not link sand to aridity or vegetation, but more the development of real solum (true soil represented by A,B horizon). This developpement of pedogenesis needs weathering and action of life (bacteria, plants). If you have aridity you have less plant and bioweathering  and soil developpment is very slow, furthermore you will have often more wind erosion (deflation).

Dear Muhammad,

you are hitting the nail on the head. Edaphic conditions refer to which plants cna grow where depending on soil and climates. However, you could imagine that, under changed climates--say wetter climates in the past, more vegetation would lead to more debris, more accumulation of organic matter in the soil and eventually better soils...

climate is always the fundamental drivers. but soils are living parts of the bosphere, and the themselves will change as a function of which plants can grow above them.

In other words, both sides of your question are correct.

Best,

Francesco

In my opinion, the key is the moisture (or the availability of rainfall/water), which controls soil development and vegetation performance. Of course, better developed soil (less sand) will allow a better vegetation development; on the contrary, better performance of vegetation reflects a better soil condition at the given moisture/water availability. The underlying cause in dry land environment is aridity (unavailability of water leading to low soil moisture ).

Dear Muhammed,

I do not agree that sandy soil are the main soils in arid environement. First of all what is a sandy soil for you, an Arenosol (WRB classification)? Or a soil where sand is the main particle size (granulometry)?

If you speak of Arenosol, yes you find them in Sahara but there are also widely areas where only hard rock is find (Leptosol) or other superficial soil less sandy , stony (Regosol)

Indeed, in arid environement, you will find also a lot of soil where salt or carbonates precipitates (Calcisol) or salt (Gypsisol, Solonchaks or Solonetz).

To conclude, I will not link sand to aridity or vegetation, but more the development of real solum (true soil represented by A,B horizon). This developpement of pedogenesis needs weathering and action of life (bacteria, plants). If you have aridity you have less plant and bioweathering  and soil developpment is very slow, furthermore you will have often more wind erosion (deflation).

To keep it very simple:

Their are two questions asked in single stroke:

1. One is related to climate

2. Other  related Soil texture.

Aridity is directly proportional to the amount of precipitation and latitudinal effect. their are various classification given by different scientist. it has no relation with soils but the latitude, proximity to sea, global atmospheric circulation and ocean currents plays very important role in aridity or humidity.

For soil formation the abiotic factors such as water, air and sun plays very important role, moisture determines the organic carbon content in the soil.

But most important is the geology of the region. Black cotton soil India and  soils of Colombia-Snake plateau in US  has same geological origin but since the climate differs, the rainfall pattern differs, hence the soil characteristics is different.

For clay formation the water (rainfall) forms main factor. Then the vegetative growth on that soils and decay of that vegetative matter in that soil nutrient cycle. Chelation, adsorption, desorption, precipitation, dissolution all take place in presence of water. This is absent in arid regions. Where only disintegration of mineral particle takes place and hence the soil is devoid of any clay mycelium.  

Soil is not single...the chemistry and microbiology plays very important role.... for that again water is important role..

Dear Muhammad,

Briefly about this issue:

• including recycling (nutrients);
• returning to normal cycles.

Best regards!

Dear Muhammad,

Greetings!

All of the answers are taking you in one single thought, "the influence of climate". Climate is considered to be the major factor of soil formation which the rate of soil development depend on the substantial amount of rainfall and suitable temperature for weathering process to take its full blast in transforming a consolidated bedrock into a more unconsolidated regolith which if advances creates a good solum for vegetation growth. Arid regions are characterized with low rainfall and an aridic moisture regime. These conditions can give you a hint what type of soil may formed in that particular landscape. Sandy soils or weakly developed soils usually dominates these regions which can supports a small number of vegetation. 

Don't forget the factors of soil formation. It can explain everything why arid areas have that kind of soil and have that vegetation. 

Wish you all the luck Muhammad.

Best Regards,

Dernie

I am going to suggest a third possibility.  The sandy soils were created by domesticated grazing animals, if there is sufficient moisture going over the area each year, like the monsoon moisture over India, Arabia, etc.  And the damages may have been done a hundred years ago or up to 5,500 years ago in certain areas.

The difference you can see is where the vegetation was preserved like in the mountains of Salalah Oman.  Grazing also removed the soil nutrients, so that even of you sowed in local native seeds to revegetate the sandy area, the seedlings may not have enough nutrients to survive and produce mature plants.  

That is my experience working on revegetation of our Great Basin desert that you can see at http://www.ecoseeds.com/greatbasin.html