Start reading NCERT more and more and again and again as much as possibble. You can then use the Arihant Publications book for solving the Multiple Choice Questions. Do solve previoues years paper also so that you get a good idea about the exam pattern and the type of questions being asked. Also keep giving subject wise tests and also some mocck tests to boost you self confidence. Another books you can study- ICAR AIEEA UG Entrance exam guide, Bsc Agriculture entrance exam guide by Lalita Gaur.

Refer to the website below for more detailed information..

https://university.careers360.com/articles/icar-aieea

Best wishes. Thank you.