Agriculture Laterite soils have a high clay content, which means they have higher
cation exchange capacity, low permeability, high plasticity and high water-holding capacity than sandy soils. It is because the particles are so small, the water is trapped between them. After the rain, the water moves into the soil slowly. Due to intensive leaching, laterite soils lack in fertility in comparison to other soils, however they respond readily to manuring and irrigation. In some places, these soils support grazing grounds and scrub forests. Laterite is mined while it is below the water table, so it is wet and soft. Upon exposure to air it gradually hardens as the moisture between the flat clay particles evaporates and the larger iron salts They harden like iron when they are exposed to air. Geographic surveys show areas which have laterite stone alignments which may be foundations of temple sites that have not survived. The stone materials used were sandstone and laterite; brick had been used in monuments constructed in the 9th and 10th centuries. It is a World Heritage site. The foundations and internal parts of the temple contain laterite blocks behind the sandstone surface.
Road building The French surfaced roads in the Cambodia, Thailand and Vietnam area with crushed laterite, stone or gravel. Kenya, during the mid-1970s, and Malawi, during the mid-1980s, constructed trial sections of bituminous-surfaced low-volume roads using laterite in place of stone as a base course. The laterite did not conform with any accepted specifications but performed equally well when compared with adjoining sections of road using stone or other stabilized material as a base.
Water supply Bedrock in tropical zones is often
impermeable granite, gneiss, schist or sandstone; the thick laterite layer is porous and slightly permeable so the layer can function as an aquifer in rural areas. The aquifer in this laterite recharges rapidly with the rains of April–May which follow the dry season of February–March, and continues to fill with the
monsoon rains. Locally available laterite—a low-grade bauxite rich in iron and aluminum—is used in acid solution, followed by precipitation to remove phosphorus and heavy metals at several sewage treatment facilities. Bauxites of economical interest must be low in kaolinite. The bauxites form elongate belts, sometimes hundreds of kilometers long, parallel to Lower Tertiary shorelines in India and South America; their distribution is not related to a particular mineralogical composition of the parent rock. They reach a maximum thickness of and once provided a major source of iron and aluminum ore. Rich laterite deposits in
New Caledonia were mined starting the end of the 19th century to produce
white metal. The discovery of sulfide deposits of
Sudbury, Ontario, Canada, during the early part of the 20th century shifted the focus to
sulfides for
nickel extraction. About 70% of the Earth's land-based
nickel resources are contained in laterites; they currently account for about 40% of the world nickel production. In 1950 laterite-source nickel was less than 10% of total production, in 2003 it accounted for 42%, and by 2012 the share of laterite-source nickel was expected to be 51%. The four main areas in the world with the largest nickel laterite resources are New Caledonia, with 21%; Australia, with 20%; the Philippines, with 17%; and Indonesia, with 12%. ==See also==