Bill,
I've been to Israel and Jordan. I'd say the ground-cover coloring depends on exactly where you are -- coastal areas, the true "desert" such as Sinai Peninsula, or somewhere in between.
For all my "desert" and "arid" terrain, I use a very simple 3 color dry-brush of acrylic craft paints (which I have custom matched at Home Depot, in order to get large quantities at a more affordable price):
1. Base coat of a slightly reddish medium-dark brown (close match to CraftSmart "BROWN");
2. Heavy dry-brush of caramel (matches Folkart "HONEYCOMB");
3. Highlight dry-brush of "sandstone", a pale shade of tan (matches Delta Ceramcoat "SANDSTONE").
Looks like this:
Here's a link to a page on my blog with some more details re: the color scheme, mixed in with how I built that river terrain board:
link
For more of a pure sandy desert finish, you can easily go heavier on the final "Sandstone" highlight coat. IMHO sticking with the brown and caramel undercoat gives some nice depth and dimension to the ground.
tackles a 
