hopping question

Can anyone tell me the reason for finish hopping in the primary. Why is this different from dry hopping?
Thanks, Dwight

czech pilsner ready to bottle, blonde lager in primary

 

Hopping in the primary is dry hopping. You'll usually want to do it in the secondary, however, in order to avoid having the hop aroma pushed out by the active fermentation and all the c02 bubbling through.

 

Ok thanks. I have read some recipes that dry hop with kent goldings during primary fermentation and was wondering of the reasons.
In the secondary it is.