Set-aside was introduced as a political measure by the European Union

European Union

The European Union is an economic and political union of 27 independent member states which are located primarily in Europe. The EU traces its origins from the European Coal and Steel Community and the European Economic Community , formed by six countries in 1958...

 (EU) in 1988 to (i) help reduce the large and costly surpluses produced in Europe under the guaranteed price system of the Common Agricultural Policy

Common Agricultural Policy

The Common Agricultural Policy is a system of European Union agricultural subsidies and programmes. It represents 48% of the EU's budget, €49.8 billion in 2006 ....

 (CAP); and (ii) to deliver some environmental benefits following considerable damage to agricultural ecosystems and wildlife as a result of the intensification of agriculture. It has now been abolished.

Set-aside became compulsory in 1992, primarily as a means to reduce the "grain mountain" as part of the Common Agricultural Policy.