Your Ginseng has lost many of its leaves. That means it either has not been getting enough light or has not been watered properly. It does best if kept on a sunny windowsill or at least close to a window. Water it thoroughly until some water comes through the drain holes as soon as the surface of the soil feels dry.
Fertilizer is not a substitute for good sunlight or proper watering. Until it recovers and starts to put out lots of healthy new growth avoid fertilizing it. When fertilizing use a liquid or powder that is diluted to half strength in water. Don't use fertilizer pellets or spikes.
The information about root pruning is accurate for those who have a serious bonsai hobby or practice. However, if you would just like to maintain a nice bonsai without a lot of extra work, then root pruning is not necessary. I have several that have been in the same pots and soil for over 10 years and they are doing just fine. However, to maintain the bonsai miniaturized shape and size, regular stem pruning is definitely essential.
