Knowledge base
Soils
Soil textures and types — their physical and chemical properties, management considerations, and crop suitability.
21 entries · every entry is sourced and dated
Texture classes are general descriptions. Individual fields vary and should be assessed with local soil survey information and testing.
- Soil type
Alluvial Soil
Alluvial soil forms from sediment deposited by rivers, streams, and floodwater. It is typically layered, often naturally fertile, and widespread on floodplains, river terraces, and deltas that support some of the world's most intensively farmed land.
- Soil type
Andosol
An Andosol is a soil formed from volcanic ash and other volcanic ejecta, dominated by distinctive minerals that give it a dark, light, porous character with high water retention and excellent structure. Naturally productive but prone to strong phosphorus fixation, Andosols support intensive cropping around volcanic regions.
- Soil type
Cambisol
A Cambisol is a young to moderately developed soil in which the subsoil has begun to change through weathering and structure formation but shows only the beginnings of horizon differentiation. Widespread and generally reasonable for agriculture, Cambisols underlie diverse farming across temperate and other regions.
- Soil type
Chalky Soil
Chalky soil is a calcareous soil formed over chalk or limestone bedrock, defined by high calcium carbonate content and alkaline pH. It is often shallow, stony, and free-draining, which limits water storage and can reduce the availability of certain micronutrients.
- Soil type
Chernozem
Chernozem is a deep, dark, humus-rich soil formed under temperate grassland (steppe) vegetation, renowned for its natural fertility and high organic carbon content. It underlies some of the world's most productive cereal-growing regions but is vulnerable to organic-matter loss and erosion under intensive cultivation.
- Soil texture
Clay Soil
Clay soil is a fine-textured mineral soil dominated by clay-sized particles. It holds water and nutrients well but drains slowly and can be difficult to work when wet or dry.
- Soil type
Ferralsol
A Ferralsol is a deep, intensely weathered tropical soil dominated by iron and aluminium oxides and low-activity clays. It typically has good physical structure and drainage but low natural fertility, high phosphorus fixation, and acidity, so productive use depends heavily on nutrient and acidity management.
- Soil type
Fluvisol
A Fluvisol is a young soil developed on recent river, lake, or marine sediments, typically showing layered deposits rather than well-developed horizons. Frequently fertile and occupying floodplains and deltas, Fluvisols support intensive agriculture, including some of the world most important rice and mixed-cropping regions.
- Soil type
Gleysol
A Gleysol is a soil saturated by groundwater for long enough to develop reducing conditions, producing the characteristic grey, blue-grey, and mottled colours of gleying. Wetness and poor aeration are its defining constraints, but with drainage many Gleysols become productive, and undrained they are classic rice soils.
- Soil type
Histosol
A Histosol is an organic soil formed from the accumulation of partly decomposed plant material under wet, oxygen-poor conditions. Undrained, these peatlands are unsuited to conventional cropping; drained, they can be productive but subside, oxidise, and release stored carbon, making their use environmentally sensitive.
- Soil type
Laterite Soil
Laterite soil is a highly weathered tropical soil rich in iron and aluminium oxides, formed under prolonged high temperature and heavy rainfall that leach away most silica and soluble nutrients. It is often naturally low in fertility but supports crops such as cassava, coconut, and oil palm with appropriate management.
- Soil texture
Loam Soil
Loam soil is a medium-textured mineral soil with a relatively even mixture of sand, silt, and clay. It combines good water and nutrient retention with reasonable drainage and workability, making it widely regarded as the most versatile agricultural soil.
- Soil type
Luvisol
A Luvisol is a soil in which clay has washed down from the topsoil and accumulated in a subsurface horizon, leaving a lighter-textured surface over a clay-rich subsoil. Common in temperate regions and generally fertile, Luvisols support much of the cereal and mixed farming of Europe and other mid-latitude areas.
- Soil texture
Peat Soil
Peat soil is an organic soil formed from partially decomposed plant material that accumulates under waterlogged conditions. It is typically acidic and holds large amounts of water, but drainage and cultivation raise significant subsidence and conservation concerns.
- Soil type
Podzol
Podzol is a strongly leached, acidic soil typically formed under coniferous or heath vegetation on coarse, sandy parent material in cool, humid climates. It is characterised by a distinctive pale, nutrient-depleted surface horizon over a darker layer where leached organic matter, iron, and aluminium accumulate.
- Soil type
Saline Soil
Saline soil contains elevated levels of soluble salts in the soil solution, raising osmotic stress on plant roots and reducing water availability even when soil moisture is present. It commonly develops in arid and semi-arid regions, poorly drained land, and irrigated areas with inadequate leaching or drainage.
- Soil texture
Sandy Soil
Sandy soil is a coarse-textured mineral soil dominated by sand-sized particles. It drains quickly and warms early in spring but holds little water and few nutrients, so it needs frequent, careful management.
- Soil texture
Silt Soil
Silt soil is a fine-to-medium textured mineral soil dominated by silt-sized particles, intermediate in size between sand and clay. It is often fertile and holds moisture well but is prone to surface capping, compaction, and erosion.
- Soil type
Solonchak
A Solonchak is a soil with a high concentration of soluble salts accumulated in the profile, usually in arid and semi-arid regions or where saline groundwater and irrigation concentrate salts. Salinity severely limits most crops, so Solonchaks are largely unsuited to conventional cropping without reclamation, and support only salt-tolerant species.
- Soil type
Vertisol
Vertisol is a clay-rich soil dominated by shrink-swell (smectite) clay minerals that crack deeply on drying and swell shut on wetting, producing self-mixing profiles. These soils can be highly fertile but present distinct management challenges around the timing of tillage and traffic.
- Soil type
Volcanic Soil
Volcanic soil forms from volcanic ash, pumice, and other eruptive material, developing into porous, mineral-rich soils classified as Andisols. These soils are valued for cultivation of crops such as coffee and tea in many highland tropical and subtropical regions.