earth soil dirt ground clay loam turf clod dust topsoil mold mould silt humus mud muck compost subsoil gravel alluvium deposit fill glebe sand shore terrane land argil fireclay brick adobe kaolin pipeclay pipestone terracotta bole slip gault pug till loess wacke clunch fertilizer dressing dung guano manure enricher maul mulch nourishment peat potash bonemeal fishmeal moss fertiliser covering protection leaves bark insulation litter straw