How does physical geography influence whether intensive or extensive agriculture is used?

Intensive farming is done where land recourse is limited.

Explanation:

Yes, physical geography (land forms, soil types, climate etc.) greatly influence the type of agricultural practice used.  

Intensive farming is practised where land resource is limited so that higher output is yielded from the same patch of land. Opposite to this extensive farming is practiced to increase yield by bringing more and more land under cultivation. Here land is not a limited resource.