The orange peels contributed two things for certain, a large amount of nutrients and organic matter that would hold and trap moisture. Both of those are very conducive to high plant growth.
I do wish they had ph tested the soil before so we could know whether the orange peels altered the soils acidity.
Burying the weeds under an impenetrable layer of mulch causes them to compost in place. The soil deepens and you get a blank slate to start over, more like a secondary succession forest.
I do wish they had ph tested the soil before so we could know whether the orange peels altered the soils acidity.