Statement: Farmers must immediately switch over to organic fertilizers available instead of chemical fertilizers for better yield.
Assumptions:
I. All the farmers use only chemical fertilizers.
II. Organic fertilizers are readily available to the farmers.
If only II is implicit
Here, 'all' and 'only' does not make assumption I implicit. Since, it is already specified in the statement that farmers must immediately switch over to organic fertilizers which are available, statement II is implicit.