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Dry leaves are a "brown" (carbon source) similar to the cardboard. If you want to up your fertility, you'll want to add a nitrogen source. If you can get goat or rabbit poo, you can add it directly to the garden without composting. With that said, more compost is always better!
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Dry leaves are great, like he says, for adding carbon to the soil, and it is carbon that catches and holds the nitrogen you need for plants to grow. So, add the leaves. I usually dig a deep trench in the fall and pile the leaves in, then cap with a thin layer of dirt and garbage. Then next time I collect leaves do another layer until the leaf fall season is done. Then all winter long the garbage and fireplace ash goes on top. In the spring I cap the whole thing with a layer of dirt and plant into that. The leaves will rot over the summer and create a deep carbon layer. This has been working very well for me the last ten years. I don't bother to actually compost any more, just bury it all deep.
This fall I started adding all the recyclable paper in the trench. We'll see how that goes, but I expect it to act similar to the leaves except maybe be slower to break down. Since it is all a couple of feet down, it shouldn't matter. With lots of pure carbon added, you do need to make sure there is a good nitrogen source, manure or garbage, or the plants will have a hard time getting enough.