The primary difference between a quota and a voluntary export restraint (ver) is that

The primary difference between a quota and a voluntary export restraint​ (VER) is that the quota is unilaterally imposed by one nation on the other while the VER is the result of negotiations between nations.
VERs are a result of requests made by the importing country to provide a measure of protection for its domestic businesses that produce competing goods, which means the negotiations are between nations.

The answer would be abrasion.

Soil? it sounds right when you r3ad it in a sentence