cristel
te mel and gerald
Dark brown or black topsoil - large amount of organic matter and is nitrogen rich.
Red topsoil - low in organic matter and will require nitrogen fertilizer to increase their fertility. 
Alfisols form in semiarid to humid areas, typically under a hardwood forest cover. They have a clay-enriched subsoil and relatively high native fertility. "Alf" refers to Aluminium (Al) and Iron (Fe).
Andisols are soils formed in volcanic ash and defined as soils containing high proportions of glass and amorphous colloidal materials, including allophane, imogolite and ferrihydrite. In the FAO soil classification, Andisols are known as Andosols.
Aridisols (from the Latin aridus, for “dry”) form in an arid or semi-arid climate. Aridisols dominate the deserts and xeric shrublands, which occupy about one third of the Earth's land surface. Aridisols have a very low concentration of organic matter, reflecting the paucity of vegetative production on these dry soils.
Gelisols are soils of very cold climates which are defined as containing permafrost within two meters of the soil surface. The word "Gelisol" comes from the Latin gelare meaning "to freeze", a reference to the process of cryoturbation that occurs from the alternating thawing and freezing characteristic of Gelisols.
histosol is a soil comprised primarily of organic materials. They are defined as having 40 centimetres (16 in) or more of organic soil material in the upper 80 centimetres (31 in). Organic soil material has an organic carbon content (by weight) of 12 to 18 percent, or more, depending on the clay content of the soil. These materials include muck (sapric soil material), mucky peat (hemic soil material), or peat (fibric soil material).
Mollisols form in semi-arid to semi-humid areas, typically under a grassland cover. They are most commonly found latitudinally in a band of 50 degrees north of the equator, although there are some in South America, South-Eastern Australia (mainly South Australia) and South Africa.
The main processes of soil formation of oxisols are weathering, humification and pedoturbationsoil profile. They are defined as soils containing at all depths no more than 10 percent weatherable minerals, and low cation exchange capacity. Oxisols are always a red or yellowish color, due to the high concentration of iron(III) and aluminium oxides and hydroxides. In addition they also contain quartz and kaolin, plus small amounts of other clay minerals and organic matter.
Most Spodosols are poor soils for agriculture. Some of them are sandy and excessively drained. Others have shallow rooting zones and poor drainage due to subsoil cementation. Well-drained loamy types can be very productive for crops if lime and fertilizer are used.
Ultisols (some varieties, such as those prevalent in the American South, colloquially known as "red clay soil") are an order in USDA soil taxonomy. They are defined as mineral soils which contain no calcareous material anywhere within the soil, have less than 10% weatherable minerals in the extreme top layer of soil, and have less the 35% base saturation throughout the soil.
Vertisols typically form from highly basic rocks such as basalt in climates that are seasonally humid or subject to erratic droughts and floods. Depending on the parent material and the climate, they can range from grey or red to the more familiar deep black (known as black earthsAustralia).
