hi vaishnavi,

all B.tech in any branch is a four-year course,  after completion of which you will be awarded the engineering degree.

talking about the agriculture branch , it is a course concerned with specific knowledge and skills in the field of Agriculture and also the job profiles associated with concern specialized roles.

right now in India, there is not much scope in this branch even if you study from a reputed college.

you might have to compromise and end up working in other fields rather than in your core field.

so I will suggest you think again about branch selection

hope this information will help.

all the best for your future