I can't speak for the north part, but I've been working on improving my soil, which is pure sand in some areas. It's definitely a challenge due to the poor moisture retention. Oftentimes organic matter just sits on the surface, instead of breaking down.
I've had success with burying the OM a few inches under the surface layer of sand. Mainly paper products, like junk mail, paper towels, cereal boxes, etc. Plus, sticks, weeds,
coffee grounds,
dryer lint, and whatever other small stuff that will break down over time. It seems to do especially well if I wet it down before burying it. On the surface, I have been keeping my growing areas covered with
wood chips, shredded leaves, and bulkier organic materials. After a year, I've noticed a difference in the quality of the soil and it's ability to hold
water longer. Instead of a fine powder that repels water and blows away in the wind, I'm seeing a darker color soil that the water seeps into & holds it's shape when I mold it into a ball. Also, since the buried OM tends to retain moisture, I'm seeing a lot more fungal activity when I dig in the dirt.