Classifying Soil Classifyingagriculture and FO Odsoil DEVELOPMENT AUTHORITY
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AGRICULTURE AND FOOD DEVELOPMENT AUTHORITY Classifying Soil ClassifyingAGRICULTURE AND FO ODSoil DEVELOPMENT AUTHORITY What is soil? to an engineer, it is a surface upon which houses and roads are built and the source of raw material. It also Blanket Peat When rock is exposed to a new environment – following lava flow, protects many of the archeological resources that are Lithosol Podzol sediment uplift, retreat of glaciers – soil begins to form. Physical and preserved in Ireland. The characteristics of a soil and how chemical weathering changes the rock, as do the actions of living they may be modified need to be known. In agriculture, one Brown Podzolic organisms. A soil eventually forms, which changes over time, as a result must know the type, quantity and quality of food that can be Groundwater AGRICULTURE AND FOOD DEVELOPMENT AUTHORITY of the rock type on which it is developed, the climate, the vegetation that Basin Peat produced on that soil. For habitat restoration, the suitability Brown Earth grows upon the soil, the organisms that lives in the soil and the topography of the soil for the original species should be known. Gley Luvisol (slope and aspect) on which the soil is found. Soil, air and water are three Builders need to know whether the land might subside or Alluvium Surface Water major factors affecting life on Earth. All three factors are strongly dependent be easily flooded. Gley Rendzina Teagasc is Ireland’s agricultural and food development upon each other. For example, soil cleans much of the water that passes authority supporting science based innovation in the agri-food through it to the groundwater and soil can act as a source or sink of carbon If the different types of soil can be classified in an efficient SANDSTONE and repeatable way, then soil characteristics are more sector and the wider bioeconomy. It delivers six programmes: dioxide and methane (greenhouse gases) to and from the atmosphere. easily communicated. Through history, classification LIMESTONE • Animal and Grassland Research Soil is an ecosystem, important for biodiversity. It is the basis of food systems have been developed for each individual country. and Innovation Programme production. It is the source of valuable materials ranging from gold In Ireland we apply the Irish Soil Classification Soil types commonly associated with particular landscape features to iron. It , from the atmosphere and http://gis.teagasc.ie/soils/. However, this means that filters water sequesters carbon • Crops, Environment and Land Use Programme comparison of soils across countries can often be very Table 1: Great groups, sub groups and series difficult. For this reason a World Reference Base (WRB) Table 2: The new Irish Soil Classification System • Rural Economy and Development Programme system was created that all countries can relate to and this allows comparisons across countries Distinguishing “Old WRB • Food Programme Group Description Great Group Description ftp://ftp.fao.org/docrep/fao/009/a0510e/a0510e00.pdf. Criteria name” correlation • Education Programme Soils are grouped according to a single dominant characteristic Ombrotrophic Blanket peat, Rain-fed peat Histosol affecting the nature of the soil. 11 Great Groups exist in Ireland. Developing a universal soil Peat basin peat • Advisory Programme Great Soils with thick For example, podzols are soils, that formed under acidic classification organic layers Groups Minerotrophic Teagasc employs over 120 scientists and 120 technicians in conditions, where iron and aluminium has been lost (leaching) Early civilisations knew that soil quality varied. In ancient Groundwater fed peat Fen peat Histosol Peat research, 30 specialist staff, and over 320 advisers/teachers Egypt, black alluvial (kemet) and red desert (deshret) were from the surface horizon and is deposited in lower horizons. Shallow calcareous soil two recognised soil types. In the 16th century, Russians Shallow or Rendzina Rendzina Regosol in education and advisory roles. In total, over 1,200 staff (<40 cm deep) described soils in terms such as poor, sandy, clayey stony, extremely are employed at over fifty locations throughout the country. Each Great Group is further sub-divided based on the main etc. By the 20th century, scientists were classifying soils gravelly Shallow non-calcareous soil The research carried out by Teagasc is essential to the diagnostic features found within the soil. Diagnostic features soils Lithosol Lithosol Leptosol on the basis of their environment and the processes that (< 40 cm deep) development of competitive and sustainable agricultural and are described as the main characteristics of a soil profile that formed them. Ultimately this was regarded as inadequate. Soil derived from alluvium. No food industries. describe the main soil forming processes and/or soil forming Systems evolved where physical and chemical features Alluvial Regosol Fluvisol distinct layer development factor taking place. Nine key diagnostic features are recognised: (pH, temperature, minerals, water, particle nature, etc.) For further information visit: www.teagasc.ie were quantitatively recorded along with the effects of Soils Groundwater Soil gleyed within 40 cm of the Gley Gleysol 1. Histic (peaty surface horizon present), processes such as those involving; leaching, gleying influenced Gley surface due to watertable. and organic matter build up and climate. by water 2. Gleyic (mottling as a result of groundwater table), Soil gleyed within 40 cm of the Surface-water Sub surface due to slowly perme- Gley Stagnosol 3. Stagnic (mottling as a result of a slowly permeable horizon), The World Reference Base Gley Groups able horizon. 4. Spodic (leaching of iron/aluminium into the lower horizon), The World Reference Base (WRB) for soil resources is Infertile acidic soils with an a more recently developed system. It draws on ideas from 5. Calcareous nature of the soil, ash-like subsurface layer. They the US, Russian and other systems. The basic concept is Podzol show effects of acid leaching. Podzol Podzol 6. Humic (organic matter in the surface horizon, but not histic), to distinguish soils according to their morphology as an Soils affected by Typically formed under expression of (similar to the system 7. Soil that has been significantly artificially drained, diagnostic features Fe/Al chemistry coniferous forest. we now use in Ireland, but with diagnostic features that increase 8. Peat soils that are cut for turf, apply to soils all over the world). The detail is comparable Brown Some leaching has taken place, Brown Cambisol to that of the US system but it omits soil climate except in 9. Anthropic soils that have been significantly changed as a Podzolic but not as severe as podzols. Podzolic or Podzol cases where the climate influences soil characteristics. result of human management. Loss of clay minerals from This system recognises 32 basic reference soil groups the surface horizon to lower (histosols, podzols, andosols and others). Globally, Soils with clay Grey brown Series consist of soils within a subgroup that have horizons Luvisols horizons (clay illuviation). Luvisol the WRB system can be used as a benchmark. A soil enriched subsoil podzolic similar in color, texture, structure, reaction, consistence, mineral Generally found in limestone classification derived from one system can be correlated areas and chemical composition and arrangement in the profile. Series with the WRB system and by extension with other Series names are place names of townlands, etc. from the area where systems. Workers can apply it (and other systems) using the soil was first defined. a ‘key’ similar to those used in biological classification. Relatively young, or soils Cambisol The table below describes each of the 11 Great Groups Brown Earth Uniform throughout. Brown Earth Series are defined on the basis of the following, hierarchically: found in Ireland in the new Irish Classification System, the with little profile or Regosol Find this and other lessons on www.sta.ie development great group, subgroup, texture and parent material. “old name” used until last year and the equivalent WRB references groups to which it can be compared. AGRICULTURE AND FOOD DEVELOPMENT AUTHORITY Classifying Soil AGRICULTURE AND FOOD DEVELOPMENT AUTHORITY Classifying Soil What is soil? to an engineer, it is a surface upon which houses and roads are built and the source of raw material. It also Blanket Peat When rock is exposed to a new environment – following lava flow, protects many of the archeological resources that are Lithosol Podzol sediment uplift, retreat of glaciers – soil begins to form. Physical and preserved in Ireland. The characteristics of a soil and how chemical weathering changes the rock, as do the actions of living they may be modified need to be known. In agriculture, one Brown Podzolic organisms. A soil eventually forms, which changes over time, as a result must know the type, quantity and quality of food that can be Groundwater AGRICULTURE AND FOOD DEVELOPMENT AUTHORITY of the rock type on which it is developed, the climate, the vegetation that Basin Peat produced on that soil. For habitat restoration, the suitability Brown Earth grows upon the soil, the organisms that lives in the soil and the topography of the soil for the original species should be known. Gley Luvisol (slope and aspect) on which the soil is found. Soil, air and water are three Builders need to know whether the land might subside or Alluvium Surface Water major factors affecting life on Earth. All three factors are strongly dependent be easily flooded. Gley Rendzina Teagasc is Ireland’s agricultural and food development upon each other. For example, soil cleans much of the water that passes authority supporting science based innovation in the agri-food through it to the groundwater and soil can act as a source or sink of carbon If the different types of soil can be classified in an efficient SANDSTONE and repeatable way, then soil characteristics are more sector and the wider bioeconomy. It delivers six programmes: dioxide and methane (greenhouse gases) to and from the atmosphere.