First let me say that I am not sure about this but I would think you would be less likely to have that (one planting only) issue with wild-simulated than you would with woods grown cultivated or artificial shade grown cultivated.
In both woods grown and artificial shade grown cultivated they are planted very thick. I read on one woods grown cultivated site that they plant at 100/lb seed per acre. Not sure if artificial shade grown cultivated is planted at about that same rate or possibly more.
Wild simulated most suggest in the 20-25 lbs per acre rate.
When densly populated there will be disease problems, they have to spray heavily, etc. I am sure that the disease problems remain in the soil after harvest and then if you replant from seed the young sprouts just don't have what it takes to fight that off even if sprayed heavily so the crop would fail.
If they waited a few years before attempting to plant again perhaps the soil would recover and the disease problems would leave.
One thing I bet you could do on wild simulated is plant your seng in measured beds (for example 5 x 50 ft) and leave plenty of room between beds (say 10' if possible). You would have to have plenty of land to space it out like that.
That would leave you room in between beds to establish other beds (say 5-6-7 years later) just before you plan to harvest the first beds that were planted.
Then after you harvest those beds you leave them be for another 5-6-7 years to allow them to recover and to become disease free again.
Again - just guessing on that but seems to me that would have a decent chance of working.
I agree with TNhunter that you would probably have less \"Replant\" problems with wild simulated than you would with woods cultivated.
From Persons ginseng book:
\"When ginseng is replanted on the same site after a first crop has been raised to maturity and harvested, sometimes the results are disastrous. Losses of anywhere from 30%-100% are reported. The exact cause of the difficulties is still unknown, but second plantings seem more susceptible to any kind of stress, especially diseases. Sometimes problems do not arise until after the plants are three or four years old and the grower has a great deal of time and effort invested in them.\"
He goes on to say:
\"I have often tried replanting in the same beds, and I have found that it is only likely to be successful where I have had vigorous groth and absolutely no disease problems the first time around. ....Try a small test plot on the used site. If it grows to maturity, then it is probably safe to replant the entire area.\"
Like TNhunter said. If you had enough land to leave some space for an additional planting. After you harvest your first planting you could seed the unused areas and at the same time plant a test plot in the areas you just harvested from (instead of waiting 7 years) and then after 7+ years you would know whether it is safe to replant all of those beds from the results of your test plots.
I would seeds all of your available land before replanting beds.