Sir, since your father owns the land and you will be his heir, you can request him to put your name in the will and your name will be added as owner after he is no more.
In case you want it added while he is alive, you can still do so as a farmer family can still transfer the land to the legal family members.
The sub-registrar checks all the conditions as correctly pointed out by the advocate above when the land is purchased and sold.
If the conditions were to be used for existing farmers, then all farmers in Gujarat would remain poor as they cannot earn more than Rs. 2 lakhs and if they earn more than that then they have to stop being a farmer. You may consult local advocate who may know better.