Planting Pits to be dug

Dear Farmers, Need your advice. I have to dig close to 3000- 3500 pits of 3 feet by 3 feet. The options that i have are

  1. Use Tractor - This is looking very expensive as of now
  2. Manual labour to dig the pit- This is extremely slow
  3. Use JCB - This while being the cost effective option still has a few drawbacks.

Is there a Agur type which i can use for getting the pit dug up or if there are any other options for getting the work done in a more cost effective but timely manner.