I haven't really finished digging because I haven't dug the area where the roots are. I will dig this new area quite deeply like I did on the other half of the bed and remove all the stone using the bread tray sieve. I think that I have done this fairly well in the area I have dug already.
I have removed considerable amounts of stone. This has been replaced by topsoil, horse manure and pigeon manure. All the soil and manures went through the makeshift bread tray sieve because it helps to mix them together.
The new topsoil has come from turfs left in the bins by the allotment gate. I sieved out the topsoil using the bread tray sieve. The grass was put at the bottom of the double digging trenches.
One of the advantages of digging is that it mixes well and manures get distributed throughout the soil profile.
If you look at the horticultural textbooks, it tells you that some nutrients come from the weathering of rocks. I considered this carefully. Stones come from rock. I am removing lots of stones from this soil. Maybe if I weather these stones by hitting them with the bull hammer and return the dust to the soil, this would add nutrients to the soil.
There may be few nutrients in quartz and sandstone but I still give them a tap with the bull hammer. Plants do not need a great deal of micro nutrient from the soil so the little that I get from stone might be sufficient.
As I was sieving out the stone from the soil, I also sieved out large pieces of inoculated charcoal that I had used in planting holes. I don't think that the larger pieces of charcoal are doing very good jobs so I am hitting them with a bull hammer to crush these too. It is all getting mixed into the topsoil through the sieve.
When using a no dig system of gardening, nutrients are put on the top of the soil in the form of compost and worms are used to distribute this throughout the soil profile.
Although digging seems to kill a few worms, there are still a great many worms to do a similar job when the soil is dug. Also there is nothing stopping me from putting a layer of compost or manure over the dug bed. In other words you can go up adding compost to the soil surface or you can go down adding compost or manure to the subsoil. Or you can do both. I would rather do both.
Digging might destroy mychorrhizal symbiotic associations and this is one of the few disadvantages to digging. However, this will occur when crop plants are harvested anyway and new associations can be promoted using commercial mychorrhiza spores. The subsoil in this bed was so hard that I could not get a spade into it. I had to use a fork. Although there were a few resourceful worms that had worked their way into it there was little evidence that many other organisms were making it their home. When I was sieving this subsoil I was mixing in topsoil from the turfs, horse manure and pigeon manure and this gave it a very friable texture. Introducing carbon (organic matter) throughout the soil profile should mean that there is a source of food for a wide range of soil organism. This should increase the soil micro organism population and diversity.
There are times when there is no need to dig so I don't dig. However, passing the soil through the makeshift sieve has produced a really fine tilth and this makes all gardening jobs much easier. I will have to earth up the potatoes next spring and summer and having this really fine tilth soil will make it much easier.
I raked over the soil after finishing digging and it was a delight because it was so easy.
Put some xCupressocyparis leylandii shreddings on the pathway between 25(b) and 26(a) and I am going to plant a little hedge of Lonicera nitida, which is a honeysuckle would you believe, along the path. Lonicera nitida doesn't have a honeysuckle sent though.