Hi Amisha,

Agricultural Engineers are the one who generally apply engineering principles and Biology principles to help in betterment of Agricultural activities.
This includes everything beginning right from:

Study of Soil
Soil / Land conservation
Irrigation facilities
Crops
Seeds and improvement in seed quality
Equipments needed to aid farming and harvesting
Proper trading
Educating the farmers regarding all the above

Mostly the engineers though is mainly in the laboratory, but an Agricultural engineers work defers to a lot of extent. He is mainly found on the field, whereby either monitoring the soil, or meeting the client and explaining him the benefits of new technology and most importantly, getting into the main field work. Whatever new technology has been designed, going on field to check its sustainability.

As far as the progress of such engineers is concerned, initially they begin with the testing phase, and then you can move on to either Sales and marketing, rather Client servicing or the Managerial role.

As such this job entails a lot of Research work.
And also stresses on extreme good communication skills.

Please be ready to get into the field and be ready to live in any kind of situation. Even though research in laboratories is your main objective, but for collecting samples and implementing of the research product you need to be on the field.

Some of the Job roles you can fit yourself would be:

• Agricultural engineers often work in teams and their duties involve analysis of current methods and equipment applied to the production, packing, and delivery of food products. They might work in a group with other engineers, or those outside of engineering, to solve problems related to systems, processes, and machines. They may be involved in designing a water
  irrigation system, or in determining alternative uses for agricultural byproducts. They may participate in legal or financial consulting regarding agricultural processes, equipment, or issues.
• Some agricultural engineers focus on machinery, and may
  design equipment used in agriculture and construction.
  These engineers might have a special interest in crop
  handling, hydraulic power, or the growth of specific crops.
  They may be employed by machine manufacturing firms.
• Other agricultural engineers may find themselves designing
  buildings or other structured used for livestock, storage of
  grains, or experimental growing facilities.
• Still other agricultural engineers might focus on developing systems for food processing, such as drying processes, distillation, or long term storage.

Hope this helps.

Wish you good luck............