Tropical+Rainforest+Soils

Temperature, climate, rainfall, and types of vegetation affect the types of soils in different rainforests on each continent. The soil in rainforests is one of the deepest in the world. Because of leaching, the removing of large amounts of nutrients, the soil lacks many fundamental nutrients. Rocks weather quickly because of constant rainfall and exposure to a lot of moisture, and along with rain washing away nutrients, there two factors have an impact on the nutrient-poor soil G7]. The topsoil is very thin but consists of decaying plants and animals which provide nutrients for vegetation [ G1]. Heavy and persistent rainfall washes away the nutrients not taken up by vegetation, which causes a thin topsoil that lacks many nutrients. Because of this, organisms depend on the recycling of nutrients, mostly contained in the vegetation G2].

G3]

__**Horizons**__ [G8]
 * O Horizon: thin topsoil (low humus) due to abundance of vegetation and decaying matter
 * A Horizon: Latosols (reddish color)
 * B Horizon: Oxisols and Ultisols
 * C Horizon: Parent Rock

__** Latosols **__ Tropical rainforest soils are latosols, soils that have a reddish brown color because of high contents of iron and aluminum oxides. There is also dense clay mixed with these compounds. As a result of the hot, wet climate and the rapid breakdown of organic material, there is a low humus content [ G4]. Latosols also have short nutrient cycles due to fast plant growth and decomposition G8].

__** Oxisols and Ultisols **__ 43% of rainforest soils are oxisols and ultisols. Oxisols are acidic, low fertility soils with high aluminum and iron oxide contents. When it is dry, oxides in oxisols form impermeable layers called laterite are formed below the surface. When the trees above oxisols are cut down, the area becomes dry and eroded which leads to the formation of laterite. This process is permanent and will not happen in the presence of trees. Rain runs off the impermeable laterite causing erosion and flooding G5]. Oxisols have low activity minerals while Ultisols have some minerals

G6]

G1]G2]G3]G4]G5]G6]G7]G8]

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