When the soil gets under your fingernails it can be quite tricky to get it off. I like to put my fingers into warm water with a bit of baking soda before I try to wash them. After washing my hands I use Vaseline Jelly on my fingers and over the nails and cuticle. After the Vaseline has sets I recommend Sally Hansen Diamond Strength Instant Nail Hardener for that extra protection and shine your nails deserve.
Good luck hand have a nice nail day!