• an increase in osmotic pressure which makes water mobilization more difficult for plants;
• toxicity of certain ions to plants (Cl^-, Na⁺, etc.);
• degradation of the soil (changes in structural state, reduction of hydraulic conductivity, etc.).

The world is losing, on average, 10 hectares of land suitable for cultivation every minute, of which 3 hectares is as a result of salinization (equivalent to 1.5 Mha per year) [Kovda, 1983]. Today it is estimated that almost 400 Mha are affected by salinization [Bot, Nachtergaele and Young, 2000].

In Africa...

almost 40 Mha are affected by salinization, around 2% of the total surface area.

In the Near East...

almost 92 Mha are affected by salinization, around 5% of the total surface area.

Access to specific data for some African countires and the Near East...

Thus the use of the term “primary” salinization, due to salts formed by weathering of rocks or natural external inputs.

20% of salt-affected land, around 15 Mha on the continent of Africa alone, have a "man-made" origin.

Thus the use of the term "secondary" salinization, introduced by human activity linked to agricultural practices, and in particular to irrigation.