How much water for fruit trees in Tucson?

I'm working with a lady who has an "orchard" in Tucson - a couple dozen various fruit trees, such as apple, peach, apricot, fig, pomegranate, etc. They are all several years old (approx. 4-6 yrs? And all are mature enough to be producing fruit.) The trees are mixed amongst each other, so she can't run a separate line to each type of tree. So the irrigation now is a "one size fits all" system. I don't think there is much in the way of mulch, other than weeds/grass that manages to grow, but mulching is part of the immediate plan.

I'm not that familiar with the desert climate, and was wondering if anybody has thoughts on how much water each tree should be getting? And should there be a plan to apply additional water when flowering and when the fruit is getting ripe?

Hi Edward:

You're lucky you're in Tucson - there's lots of resources there!

Brad Lancaster's book, Rainwater Harvesting for Drylands and Beyond has a chart in the back that shows how much water various types of fruit trees need and breaks it down to inches by month for deciduous and evergreen trees. Any of your stone fruit or pomme fruit will fall into the medium or high water use categories. Here's the pdf posted on his site. Check out the watering schedule on page 5.

Also, consider signing up with Watershed Management Group. Their Green Living Co-op implements things like earthworks and greywater harvesting to water urban orchards in the Tucson area.

Thanks Jennifer, that segment of the book was awesome. Exactly what I was looking for!

Any guideline you find "depends"...on local conditions. Why not let observation tell you? I would start out with maybe 3 emitters per tree and watch them. When the first one starts to droop just a bit, water them all. Trees native to drier climates, like the pomegranate, might do with less....you could give them fewer emitters or use a separate line run less frequently. A lot of things will survive, and maybe produce a little, on less water than you'd give for maximum yields, so there's that to consider. When I was growing veggies for market, I was taught that when you see any wilting at all, even in the heat of the day, you're losing yield and quality of just about anything.