Tracer I haven't dealt with soil that is too warm...generally stuff that is too cold. I grew up in western NY after all
That being said, one method that regulates soil temperate, keeps weeds down, and increases water efficiency exponentially is getting some agriculture cover material. Again I don't have experience with it in extreme heat, but it may help keep things a little more cool. It would also minimize any loss of moisture to evaporation. Just make sure you are leaving a good 30 inches of space between the holes you cut in the material for the plants. Edit: Sorry the spacing is dependent on what kind of plants you have, and how much space

This picture depicts a good use of the white plastic, which would I think be preferred in your climate. You can also see how they staked right down the middle of the plastic. In my experience we staked down either side of it and had double rows...but that is up to the grower.
Also if you are going for water efficiency I'd look into a gravity-fed drip irrigation system. They are pretty cheap and easy to make...the only downside is you have to regularly check the lines for any clogs. These will become immediately noticeable when one plant is 4 feet shorter than all it's neighbors.

However, the time it takes to check the lines negates time that would usually be spent watering by hand.
Feel free to PM me if you like some more information, I'd love to help.