SOIL LEACHING PROCESSES

i) Takes place in humid tropical areas with high temperatures and rainfall.

ii)During the wet season, soluble mineral salts in the top layer of the soil dissolve in water.

iii)The dissolved minerals such as silica and other bases are deposited further downwards to lower layers.(desilication)

iv)Insoluble minerals such as iron and aluminum accumulate in the top layers, to form a crust.

• Ferralisation

• Podsolization

• Eluviation

• Ribification

i)It occurs in cool climate areas where rainfall is more than evaporation.

ii)The areas experience severe leaching.

iii)Horizon ‘A’ is leached of all minerals including iron,aluminium and humus.

iv)This leaves behind soils which are grey-white or ash-like in color.

• Podsolization

• Calcification

• Salinization

• Illuviation

Mechanical washing down of minerals like clay from the upper layer into middle or lower layers. I.e. from Horizon A to B by percolating water.

• Elluviation

• Illuviation

• Cheluviation

• Calcification

i)Occurs where rainfall is lower than evaporation

ii)High evaporation moves minerals in solution form/results in the re-deposition of mineral from horizon ‘B’ to horizon ‘A’ .

• Cheluviation

• Elluviation

• Illuviation

• Salinization

i)Common in areas which experience dry conditions alternating with rainy seasons such as semi-arid areas.

ii)The soils are dehydrated during the dry season and leached during the rainy season.

iii)Soils formed have low moisture and are bright red in color.

• Ribification

• Calcification

• salinization

• Ferralisation

i) Occurs in areas where the amount rainfall is almost the same as evaporation rate.

ii)Therefore this results in the formation calcic horizon enriched with calcium compounds within the same profile as there is no movement of leached materials from one horizon to another.e.g. within B and C.

iii)This results in the re deposition of calcium compounds within the same profile.

iv)Its common in the continental interior where the surface is covered by limestone rock and receives very low rainfall.

• Calcification

• Podsolization

• Ferrilization

• Ribification

i)It occurs in areas with dry climate

ii)This process results in the soils being leached upwards through capillarity as evaporation is higher than rainfall.

iii)It involves enrichment of soil with salt as water is lost to the atmosphere through evaporation. The soils are saline.

• Podsolization

• Ferralisation

• Salinization

• Chelluviation

Is the down ward movement of materials in the soil through the influence of organic agents such as acids rather than water.

• Elluviation

• Illuviation

• Ribification

• Cheluviation