What about alkaline soil?

Better alkaline than acid. Is it a naturally high pH soil i.e. is it overlying limestone or chalk, or has it been unneccessarily limed in the past?

pH8 is high, any higher and you will start to find phosphate, boron and manganese defficiency as they will be tied up in the soil and not available to the plants. Manganese is quite commonly seen on alkaline soils when the soil warms up and crops grow faster than their roots. Crops look pale and stare,i.e. sit up and look not quite right. Usually this is temporary but if it continues the tips of onions and shallots go white and the leaves of beet, lettuce and runners become mottled with shallow poc marks.

If it is naturally alkaline there is little you can do. Plenty of organic matter, especially manure, is what it will need.

If it has been overlimed, again give it plenty of muck and lay off the lime for a year or two.

You can reduce alkalinity with sulphur. I do not know much about using it but I can see a danger of going too far.

Wow, lots of good information. All I know about the soil is that the tests all showed pH 8 and it is currently part of a stubble field which was used to grow either wheat or barley (I suspect wheat) this year.