There are few criteria for purchasing land in Karnataka. You need to be an agriculturist and annual income should be within 25lakhs. agricultural land should be either in your name or your father's name to prove that you are an agriculturist or even grandfather name to declare you belong to agriculturist family. if not you can obtain permission from DC and give undertaking that, within one year from date of purchase you will cultivate land and for five years will not sell the land.

See there are two condition for same first is if your are agriculturist then based on documents of your agriculture land you can purchase same. Second is that your family income is below 25 lakhs and with permission of deputy commissioner you can for purpose of agriculture purchase the agriculture land. 

• Mother/Parental Deed – to trace the origin of the property.
• Relevant conveyance deeds.
• Grant Certificate, if any.
• Family trees (if required)
• Relevant mutations records.
• Record of Rights.
• Survey map.
• Village map.
• And your family income should ne within 25 lakhs pa

Specific laws are there for every state. First ot all identify the land and then proceed to the revenue department and find out any conditions which have to be satisfied before the land can be bought.

Before purchase of agricultural land check whether mutation of land is done in name of seller 

2) check whether seller has original chain  of documents of title 

3) take 30 years title search of land 

If your annul income is less than 25 lacs. You can buy without any hassle. Agriculture status of other state not valid in Karnataka.

 - As per rule in Karnataka for purchasing agricultural land:- 

1. You need to have agriculturist roots in Karnataka ( i.e: Family /extended family has to have documented evidence of farming)
2. For a non-agriculturist , your annual income should be less than 25 Lakh P.A .Previously this was only 5 Lakh P.A which was hiked recently to 25 Lakh Per Annum. Hence

- You should approach to concerned district Deputy Commissioner ‘s office , for getting agriculture family certificate and to apply for permission to buy land.

- But the permission is granted with a condition that you will cultivate the land for 5 years from the date of purchasing the land.

1. Khata certificate of land. 

2. Encumbrance certificate of land. 

3. Title deed of land and category of owner as you cannot buy SC ST community land if you doesn't belong to same category.

You first get the copies of all the documents and produce them before any local lawyer,  seek his opinion,  he will suggest you to obtain the other necessary documents also,  which you can procure.