We have a fix for that, it's called earth bag. Or humorously, dirtbag :)
You put soil approximately suitable for rammed earth into sacks and then place them in courses with barbed wire between them, which provides tensile strength. The soil mix can actually be a bit more variable than rammed earth because of the sacks. If you use plastic bags they can't rot. You stucco or otherwise similarly cover the result to protect it from weather.
This tech lends itself to making both round and organic shapes. You can also use to just build walls. If you make the walls curve back and forth, they self-support. There's a photo of such a wall that was hit by a truck. Truck totaled, wall lost some covering (which was just troweled-on mud in this case) but was otherwise unaffected.