I love the colors in the sky, and the textures on the ground. I really wonder if there wasn't more color down on the ground though... Did you desaturate it? I think I would vote a little higher with a tiny bit more color. But as I said, I love the textures. Good luck in the challenge!
The bottom part of this image is very pleasing, but I think that the image as a whole would be more effective if you cropped about half of the sky out.
I like this effort but I think the color and lighting is a little flat. I also would have maybe chosen a different position to shoot from so that the foreground is a bit more interesting, maybe another beautiful cactus or other plant. That patch of dirt to me takes a bit away from the beautiful landscape. I like the fact that you chose a small aperture so everything is in the same level of focus.