Hi there and thanks for all of the quick replies!
For sure I am going to integrate cover crops / green manure in the aisles. I already pinned down which ones I can use in my situation which are vetch and oats, which is quite typical in my area, but intermixed with mustard since I need to continue the soil decompaction. Thanks for suggesting the alfa-alfa. I should look more into it for varieties that are more drought resistant. As for the sanfoine, I didn't know about it, it seems to be a very interesting crop to try out. The only thing is that the seed company
that I was suggested says that it needs a freely draining soil, which is not exactly what I have there. But it surely is a crop I'll consider now when the soil type is appropriate.
I mentioned the soil type, but I'll be more specific now: silty-clay loam in the first 30 cm and clay loam deeper down (I think I specified it really badly in my initial post...apologize)
Thanks for suggesting so many options for woody shrubs or coppiced trees.
I think the siberian pea shrub can be a candidate for sure, but I'd need others.
Elaeagnus umbellata might be one of the or even Elaeagnus ebbingei if, as TJ mentioned, there is no restriction)
I think Caragana needs a more humid situation that the one we are in, and lespedeza bicolor also seems to need a more draining
soil type. One of the big doubts that I have is if species that are said to be thriving in a specific soil type can't adapt at all to other soil types, for example if those that are said to be needing soils with good drainage might not adapt to clay soils....at the end of the day I don't need these plants to be productive in the same sense as the fruit trees will need to be, but I guess if the soil type is too challenging will eventually die or just their growth will be very stunted.
As for the suggested trees, I would rather not use them, even if just for the fact that need pruning every so often (especially the black locust). I prefer to reduce the amount of work if possible
and don yet have animals to do this type of work for me, nor would I want to introduce goats, for example, in a newly plated olive plantation.
So thanks so far for all the suggestions.
If anybody has more ideas please go ahead!