I think the previous question you asked on this subject received a sensible answer - double digging isn't necessary every year, basically that was something largely invented to keep a large staff of gardeners busy during the winter when there was not much else to do. If your beds were properly prepared initially, then adding manure, green or otherwise, to the top of the soil regularly should mean you don't have to dig.

Better to add your, I hope, 'well rotted' horse manure in the autumn and let it work its way into the soil over winter. Double digging as Bamboo says is not necessary once the initial work of preparing the beds is over.
A book you might want to try getting from your local library is 'Organic Gardening the natural no dig way' by Charles Dowding. published by Green Books ISBN 9781903998915.

See my reply on the other post with the same question.