Why do turnover happens? What strategies help to reduce the staff turnover?

you can have meeting with them, asking them about the problem they are facing, you can make them feel that they are part of making decesions 

Proper training and then a training evaluation (recap of all you've learned through training).

That is the most efficient way of minimizing employee turnovers. 

Not good motivation

Bad management

Rotation occurs due to poor candidate selection in the right place - Strategic truth to reduce the employment rate of rotation must interfere with senior management to reduce them, and you must know or stand on the causes and find the best ways to addressed

The absence of good organization

And the lack of plans for the future

Mismanagement

Lack of development

Lack of Alastaqraalozifa

The lack of security in the workplace

Lack of respect for employees

Make the employee looking for another place