Rules to be followed for Selling Agriculture Land In Karnataka

My father is agriculturist and want to sell the land as not having enough water resources to further continue that piece of land. 1) What are the legal steps & rules we need to follow to complete the deal start to end? 2) Purchaser will give some amount as advance and then some amount after some preriod (6 months)? What procedure we need to follow here? DO i need to do some registry, prepare a documents where everything we will mention about this deal, transactions, period, if & then about transactions if not followed? 3) If initial amount given, then do we need to handover land to him still not completed transactions? 4) If he refused to return back the land after initial payment and not completed the other payments? To avoid this what pre-conditions/ documentary steps we need to take legally to avoid any set backs in future? 5) What is the Income Tax angle once deal completed and amount received as purchase deal? Like consider if payment is around 20lac? 6) Legally methods to accept --- Transaction to be cash or cheque? to be safer to avoid any legal battle? Y I Patil Belgavi, Karnataka