My rotation plan goes Legume/leaf/fruit*/root, based on the part you harvest, ie1) beans/peas, 2)brassicaes/salads/celery,3)cougettes,squash etc 4)carrots,parsnips,beet,celeriac, spuds.
Put in other terms:1)plus own compost,2)plus lime/ash, compost&manure 3)plus manure 4)compost plus leafmould selectively when planting
I do not dig.
Add compost to seed rows .If your soil is shallow, grow stumpy varieties while you build it up, even if its 'tight', carrots will go down. Recommend realseeds Giant red carrot, good for 200mm in undug soil.
Would not sieve anything(except preparing composts, woodchip maybe, to remove chunks, twigs stones), if you are growing for showing (ie longest wins a prize), plant in oil drums and water at the bottom.
*Fruit as refered to, not including soft fruit-they are elsewhere.
Its my observation that many allotment holders spend too much time "faffing about", whereas their time could be more productively spent growing crops. I've asked for a tin hat for Christmas!