potatoes

Grow some mustard as a green manure in the bed first, it can help deal with wireworms which can be a problem for spuds. Bear in mind that it's a brassica though, so keep  that in mind for your rotation plans.

Be very careful of any missed from the previous year. They can develop into "volunteers" carrying the "B" word!

Professional spud growers must use the same land every year so see if you can get any info from them and also look at the RHS website.

I know a number of growers in this area who have used the same piece of land for spuds for 6 or 7 years with no obvious  ill effects. Two of them add large amounts of well-rotted manure each year but I don't know what pest control methods they employ. Not saying we should all be doing this but people can get a bit hung up on crop rotation. I can understand the sense of it when growing on a field scale but for a small veg. plot with so many different crops in close association it may not be as critical as some think. I've often wondered how square foot gardeners manage their rotation. I suspect that most soil-borne pests are able to move more than a foot or two in any direction.