I see a lot of rice hulls that are burned after harvest seasons. Is there a good use for it in my garden or it is best suited for large scale farming like rice and corn? Is there a good use for its ashes?
Rice hulls would make a decent mulch:
Rice hulls are very lightweight and in order to be used satisfactorily as a mulch, a thin layer of dirt must be spread over them, then gently but thoroughly moistened. This way they will hold their position the rest of the season controlling weeds and conserving moisture.
The ash is high in silica, and the hulls themselves are fairly nutrient-poor to begin with; I'm not sure it would be much benefit for your garden.
If you can get your hands on the unburned hulls, I'd use them for mulch as described above. Wikipedia also says they also make good insulation, so if you have a greenhouse or other situation that would benefit from this insulation you could use it there.