Uhm, okay. Anything specific about the dirt that makes it not look like dirt? How should I go about fixing this? You've been awfully vague as to any possible solution to this problem.
hehe, sorry about that. The circles don't read as being dirt, dirt doesn't contain such large particles. Smaller bits should be used. Also, only two colors are really visible in the dirt, so that third one should be more visible, make it lighter.
Here's a reference pic from Secret of Mana 3:
http://web.cs.wpi.edu/~claypool/courses/frontiers-06/samples/pixel-artist/13.gifTop-down, but that doesn't really matter for something like this. Dirt is dirt is dirt, looks the same from every angle, imo at least.