I posted a similar one a few days ago; I guess I just like cracks! The other one was b/w, this one shows the natural color of the mud. The little dead plant in the center is 1/2" long at most.
What makes this such a great abstract in my opinion is a couple of things: 1) you know immediately that it is mud, but the composition takes you beyond that; 2) the natural progression you have captured, from small chunks, to medium, to large. This creates a very nice progression for the eye to follow.
There's a stick or a twig or something that's near the middle. It's only a minor distraction, but I thought I would mention it.
I think it was a good idea to stick with colour. The browns look rich to me, and there's a light brown sheen on the left side of the photo which suggest a hint of moisture. My eye is drawn to all the great lines here - I could look around for awhile! The best part? The big, bold lines. They're really attention grabbing!