Dirt farming is the ability to renewably farm dirt without having to mine it from surrounding environments.
This manual method uses the crafting recipe of 2 dirt and 2 gravel to create 4 coarse dirt, which can be converted back to 4 normal dirt by using a shovel or hoe, and then mined with a shovel. It is also very cheap to do and since gravel is renewable through piglin bartering, if you set up a piglin farm, it can allow you to gather up several stacks of dirt without destroying the environment in the process.
When an azalea grows, whichever block it grows on turns into rooted dirt, which can then be turned into path blocks and then mined by using a shovel without Silk Touch. Or, you can right-click the rooted dirt and you will get a root along with a block of regular dirt. This can be partnered with a stone generator, moss blocks and a TNT duper to renewably farm dirt. Here is a tutorial video on how to build a farm that will give you infinite dirt, moss and wood.