Dryland orchard techniques

Hello I'm looking to gather some different ways to help out a non irrigated orchard. In my area we get about 18 to 20 inches of precipitation a year with some of that coming as snow and entering the ground via snow melt. So my methods to help hold the moisture in the ground Is keeping the grass short so it doesn't loose moisture through evaporation, mulch mulch mulch around the trees themselves I've been using horse manure and straw. There may be a small area where water can flow down hill so I will be damming it up with lots of logs and other organic debris.

What other techniques are there for a dry land orchard?

Spacing: with 60inch of rain plants only need 10ft of rootspace to get all their water, with 30inch they probably have a 2x the rootspace (20ft) and with 15ft of rain they might need 4x (40ft) of rootspace. So don't plant your trees as close.

TapRoot: plant seeds and then graft a named cultivar, that way there will be a 40ft tap root vs transplanted trees with roots that only go down 3-4ft. Never reaching that deeper moisture.

Mulch: This will help cut down evaporation. And also help water to inflitrate

Swales: this will cut down sheeting on 'flat land" and give your water a change to soak in. You can plan right by te collecting swale.

Mushroom: They actually take oxygen in and release WATER + CO2 as waste. Yes it releases WATER. Water, glorious water.

Mushroom: The mushroom "roots" are better at getting minerals and water from the soil, so the trees actually like to outsource the job, for a bit of sugar which the mushroom love.

You might have to do some irrigation, just flood the swales once a week and/or drip irrigation

Digging a shallow pit to grow your trees in can make a huge difference, but only if the tree in question can handle wet roots in a wet season. I've grown some tropical rainforest palms that need high rainfall this way in my much cooler, much drier climate. Digging a shallow pit right out to the eventual dripline (make sure you put all the topsoil back) and deep mulch will have the same effect as significantly higher rainfall.

If you have stones and rocks, try them as mulch.
It would be cool if you could post a photograph with your work.

I've tried stones and rocks with grapevines in northern az it works! definitely holds water under the soil and keeps from drying out.Still need to water though as the plants get parched.Mulch works miracles.In Hopi they use mulch and stones for their orchard.they also use alot of water catchment it is very important for keeping orchards alive out here.Mulberries,apricots,navajo peaches,persimmons once established seem to thrive out here.Apples pears plums need alittle more tlc.

Thank you for reminding me about the effects of stones have collecting and holding water I definitely will lay some down among the rows. It works well as the fence line 100 feet over has lots of good sized stone rolled under it.