Yes, your shed does need a base. This is to give it a solid, level foundation. Open soil will not help with the longevity of the shed itself or the contents within. The best materials to use to make your shed base are concrete, natural stone or wood.
Isle Of Coll
Coll is an island located west of the Isle of Mull in the Inner Hebrides of Scotland. Coll is understood for its sandy coastlines, which rise to develop huge sand dunes, for its corncrakes, as well as for Breacachadh Castle. It remains in the council area of Argyll and Bute. Coll is about 13 miles (20 km) long by 3 miles (5 kilometres) vast and has a population of around 150. Coll's sandy coastlines rise to create big sand dunes. The acme on Coll is Ben Hogh in the mid west of the island, a ridge with two tops running NW/SE, which climbs initially to a height of 104 metres (341 feet) with a triangulation column, as well as to 106 metres (348 feet) 450 metres (492 yd) to the southeast. In the 2011 census, the island's population was recorded as 195, standing for a boost over the previous decade of virtually 19%.