Random Worldbuilding Questions (Biology, Geography, Society, etc.)

[Geostationary]

RE desert farming:
While some plants can pull nitrogen out of the air, phosphorous and potassium can be a bit harder to come by. I doubt very much that you could grow anything on silicon beads + water + sunlight + air.

Check fertilizer on wikipedia? Perhaps have more info there.

First you should ask what kind of desert we're talking about- Saharan? Gobi? Kalahari? They're all very different, but all are deserts. Some are more suitable for plant life than others.