Using the NAP planting pattern

Hi
I've seen the NAP planting pattern used in The Permaculture Orchard, where Stefan Sobkowiak combines a Nitrogen fixer an apple and a pear/plum tree in the same line and staggered in each line
I wonder if this type of planting pattern can be used to include other types of fruit trees such peaches, nectarines, cherries, loquat, figs, mulberry etc.
Also I see that he uses 2 fruit trees following each Nitrogen Fixing Tree (NFT) instead of 1 NFT after each fruit tree (to maximize Nitrogen fixation as well). I guess that since he has a commercial orchard he prefers to maximize the number of productive species. Still I think if a NFT is replaced by a NF shrub I could probably interplant one right after each productive tree without loosing valuable space. The only caveat here could probably be that NFT would last longer than shrubs, and these latter might be overgrown by the fruit trees at some point.

Cheers

I like the 25% to 33% nitrogen fixers at maturity. They both work.
That said, the spacing is for trees at maturity, but at planting they are only 3ft vs 18ft.
So I propose planting 2 nitrogen shrubs between all the trees, NAP is now NnnAnnPnn[NnnAnnPnn], 7/9=78% N
For the folk who do 25% N at maturity aka NAPX, it is now NnnAnnPnnXnn. 9/12=75% nitrogen fixers at establishment.
As the fruit trees matures the nitogen fixing shrub aka n will be culled but 1 nitrogen fixing tree will be left even at maturity.
I actually aim for 90% nitrogen fixers, and so I will plant up to 6 nitrogen fixing shrubs between the NAP, but that is alot more culling work/biomass.

For the noobs in the front row (me) what the X in NAPX?  I have a Chunk of apples and cherries to be putting into the ground next month and I've been looking into the NAP method.  It seems like shrubs will really work in condense the groups I have planted near the cabin and it would be a convenient plant for my other perennial fruit (strawberries, raspberries, currants and gooseberries plus shrubby herbs).

X for eXotics or unknown like jujube, persimmons, filbert, etc.

So this would be a method to incorporate things like say, nut trees?

I like the X because unlike like A and P which are both subfamilies of the rose family, where A = apple/pear/quince/etc and P=prunus/plum/peach/apricot/cherry.
Each X is usually from a different family, so it quickly add alot of diversification. And yes it dies include nuts. I would stay on the short nuts though, if your fruit trees are 18ft, I would aim for the same height nuts, so almond, hazelnut, pistachio, yellowhorn. 50ft black walnut might need there own little subsection of the food forest.

I want acorns and chestnuts mostly.  I know my cherries are coming from softwood cuttings of a big tree outside the place we're currently renting.  Just rooting them, no grafting, so they'll be pretty stinking' huge.  The apples however are coming from a nursery and are on semi-dwarf root stock.  I can take cutting form them later and let those root and grow to standard size instead of grafting, but the first ones aren't as big.  they'll probably be situated closer to the cabin.

For the folk who do 25% N at maturity aka NAPX

What is the rationale for NAPX? that is, using the original pattern from S. Sobkowiak, unless NF shrubs are used in between fruit trees, it seems to me that some of the NFTs will remain far away from some of the trees to have a noticeable influence, especially after the shrubs are culled.
Do you know real life examples of this arrangement?
What do you think S. Bengi?

I thought the same thing too until I zoned out and realized that each plant is like a hexagon with 6 sides and 6 neighboring trees. With NAPX, 2 of those 6 neighboring trees is a nitrogen fixer.


Simplified

I remember about Darren Doherty, having interplanted 2 tagasaste trees (heavily pruned) between every 2 productive trees (in a project he was managing a few years ago) and eventually realized that they were too close and some competition ensued between the fruit trees and the NFTs..
So I guess it depends on the shrubs/trees in use if this pattern is eventually viable (I mean the one with 2 NF shrubs in between)

Yes the nitrogen fixing shrub will cover 80% of the soil and sunlight which is fine at establishment but you will have to cull them as the food system matures to the point where there is no shrub left and all you have is the nitrogen fixing trees which gives you only 25%-33% vs 80%. also due to the fact the extra nitrogen fixers are shrubs, even if we did nothing they would be shaded out and die. It could even be dutch white clover which fixes 200lbs of nitrogen per acre, esp if the scale that one is working on the just a potion of the side yard in the city vs acreage from converting a commercial orchard.