I'm new here, but from the group name, it seems to be the place for this.

We recently bought a home in rural Southern Utah. Zone 10. It is basically
sand dunes on top of lava caps and caliche.

Our back yard is a rolling sand dune. We got the irrigation water system
working this past summer, and what a mistake! I now have lots and lots of
cockleburs. Little spiky spheres about 1/4" in diameter. I went out and
sprayed Roundup on them and the other weeds and grasses I wanted to kill,
but it only killed about half of them. I took a large propane weed burner
to the rest of them. Some burned down, but some still have green centers
that lived.

I have since removed all Rain Bird Maxi Paw sprinklers. I have sprayed with
Roundup, and got the big concentrate bottle so I can spray more during this
winter. At the end, I will burn it again, and have my BIL come in with his
tractor rototiller to turn it over so I can rake out the roots. Maybe some
of the eight billion cockleburs will bury in the soil and not germinate due
to the Roundup.

Is this the logical approach? Suggestions which would be easier or better.

When finished, we'll coutour the yard, place retaining wall, reinstall the
sprinklers, and start from scratch. I just don't want a lot of weeds
sprouting through the new grass.

It's probably going to be constant war trying to keep the windblown seeds
and bird borne seeds from getting hold in the new grass.

Steve