I think that Green Manuring is as controversial as No Dig Gardening and, arguably, they are both part of the same set of ideas. Lots of gardeners use rotovators and packaged nutrients and Charles appears to use neither – but his compost includes quite a lot of imported raw ingredients. Charles’s priority is maximum yield with minimum work and who can argue with that? Charles is a commercial grower.
As far as I can understand these things, growing green manure is not primarily intended to increase the availability of nutrients – its purpose is to prevent the unnecessary loss of nutrients whilst protecting the soil from surface erosion and improving sub-surface soil structure.
I may be wrong, but I think that all forms of cropping will remove nutrients in the short term – if we want to grow vegetables intensively, then there has to be a way to quickly replace the previous crop’s depletion of nutrients. Deep-rooting green manure might be a part of the answer – simply ‘Not Digging’ will not, on its own, create a source of fresh nutrients.
Ken