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44-595: Vasily Vasilevich Dokuchaev is commonly regarded as the father of soil science , the study of soils in their natural setting. He developed soil science in Russia, and was perhaps the first person to conduct broad geographical investigations of different soil types. His contribution to science did, figuratively, "put soils on the map". He introduced the idea that the geographical variations in soil type could be explained by other variables besides geological factors ( parent material ), such as climatic and topographic factors, and by

88-696: A moon of Saturn, and Triton , a moon of Neptune, have atmospheres mainly of nitrogen . When in the part of its orbit closest to the Sun, Pluto has an atmosphere of nitrogen and methane similar to Triton's, but these gases are frozen when it is farther from the Sun. Other bodies within the Solar System have extremely thin atmospheres not in equilibrium. These include the Moon ( sodium gas), Mercury (sodium gas), Europa (oxygen), Io ( sulfur ), and Enceladus ( water vapor ). The first exoplanet whose atmospheric composition

132-599: A more refined understanding of soil. In 1998, the World Reference Base for Soil Resources (WRB) replaced the FAO soil classification as the international soil classification system. The currently valid version of WRB is the 4th edition, 2022. The FAO soil classification, in turn, borrowed from modern soil classification concepts, including USDA soil taxonomy . WRB is based mainly on soil morphology as an expression of pedogenesis . A major difference with USDA soil taxonomy

176-508: A planet from atmospheric escape and that for some magnetizations the presence of a magnetic field works to increase the escape rate. Other mechanisms that can cause atmosphere depletion are solar wind -induced sputtering, impact erosion, weathering , and sequestration—sometimes referred to as "freezing out"—into the regolith and polar caps . Atmospheres have dramatic effects on the surfaces of rocky bodies. Objects that have no atmosphere, or that have only an exosphere, have terrain that

220-405: A product of chemical transformations of rocks, a dead substrate from which plants derive nutritious elements. Soil and bedrock were in fact equated. Dokuchaev considers the soil as a natural body having its own genesis and its own history of development, a body with complex and multiform processes taking place within it. The soil is considered as different from bedrock. The latter becomes soil under

264-451: A variable amount of water vapor is also present, on average about 1% at sea level. The low temperatures and higher gravity of the Solar System's giant planets — Jupiter , Saturn , Uranus and Neptune —allow them more readily to retain gases with low molecular masses . These planets have hydrogen–helium atmospheres, with trace amounts of more complex compounds. Two satellites of the outer planets possess significant atmospheres. Titan ,

308-464: A wide range of velocities, there will always be some fast enough to produce a slow leakage of gas into space. Lighter molecules move faster than heavier ones with the same thermal kinetic energy , and so gases of low molecular weight are lost more rapidly than those of high molecular weight. It is thought that Venus and Mars may have lost much of their water when, after being photodissociated into hydrogen and oxygen by solar ultraviolet radiation,

352-474: A world with a growing population, possible future water crisis , increasing per capita food consumption , and land degradation . Soil occupies the pedosphere , one of Earth's spheres that the geosciences use to organize the Earth conceptually. This is the conceptual perspective of pedology and edaphology , the two main branches of soil science. Pedology is the study of soil in its natural setting. Edaphology

396-709: Is Russian Chernozem (1883). As a result of Dokuchaev's research, a number of Russian terms became part of the international soil science vocabulary (for example, chernozem , podsol , gley , solonets ). A crater on Mars is named after him, and the Dokuchaev Award, an equivalent of the Nobel Prize in the field of Soil Science, was instituted by the International Union of Soil Sciences in his honor. Dokuchaev published in 1869-1901: 285 works, including 61 books and 4 maps. Soil science Soil science

440-439: Is a layer of gases that envelop an astronomical object , held in place by the gravity of the object. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A stellar atmosphere is the outer region of a star, which includes the layers above the opaque photosphere ; stars of low temperature might have outer atmospheres containing compound molecules . The atmosphere of Earth

484-760: Is classifying texture as heavy or light. Light soil content and better structure take less effort to turn and cultivate. Light soils do not necessarily weigh less than heavy soils on an air dry basis, nor do they have more porosity . The earliest known soil classification system comes from China, appearing in the book Yu Gong (5th century BCE), where the soil was divided into three categories and nine classes, depending on its color, texture and hydrology. Contemporaries Friedrich Albert Fallou (the German founder of modern soil science) and Vasily Dokuchaev (the Russian founder of modern soil science) are both credited with being among

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528-414: Is composed of nitrogen (78%), oxygen (21%), argon (0.9%), carbon dioxide (0.04%) and trace gases. Most organisms use oxygen for respiration ; lightning and bacteria perform nitrogen fixation which produces ammonia that is used to make nucleotides and amino acids ; plants , algae , and cyanobacteria use carbon dioxide for photosynthesis . The layered composition of the atmosphere minimises

572-423: Is covered in craters . Without an atmosphere, the planet has no protection from meteoroids , and all of them collide with the surface as meteorites and create craters. For planets with a significant atmosphere, most meteoroids burn up as meteors before hitting a planet's surface. When meteoroids do impact, the effects are often erased by the action of wind. Wind erosion is a significant factor in shaping

616-588: Is one of the main factors involved in Horton overland flow , whereby water volume surpasses both infiltration and depression storage capacity and begins to flow horizontally across land, possibly leading to flooding and soil erosion . The study of land's depression storage capacity is important in the fields of geology , ecology , and especially hydrology . Atmosphere An atmosphere (from Ancient Greek ἀτμός ( atmós )  'vapour, steam' and σφαῖρα ( sphaîra )  'sphere')

660-446: Is related to the various associations concerned. Indeed, engineers, agronomists , chemists , geologists , physical geographers , ecologists , biologists , microbiologists , silviculturists , sanitarians , archaeologists , and specialists in regional planning , all contribute to further knowledge of soils and the advancement of the soil sciences. Soil scientists have raised concerns about how to preserve soil and arable land in

704-631: Is that soil climate is not part of the system, except insofar as climate influences soil profile characteristics. Many other classification schemes exist, including vernacular systems. The structure in vernacular systems is either nominal (giving unique names to soils or landscapes) or descriptive (naming soils by their characteristics such as red, hot, fat, or sandy). Soils are distinguished by obvious characteristics, such as physical appearance (e.g., color , texture , landscape position), performance (e.g., production capability, flooding), and accompanying vegetation. A vernacular distinction familiar to many

748-401: Is the lowest layer of the atmosphere. This extends from the planetary surface to the bottom of the stratosphere . The troposphere contains 75–80% of the mass of the atmosphere, and is the atmospheric layer wherein the weather occurs; the height of the troposphere varies between 17 km at the equator and 7.0 km at the poles. The stratosphere extends from the top of the troposphere to

792-646: Is the study of soil as a natural resource on the surface of the Earth including soil formation , classification and mapping ; physical , chemical , biological , and fertility properties of soils; and these properties in relation to the use and management of soils . Sometimes terms which refer to branches of soil science, such as pedology (formation, chemistry, morphology, and classification of soil) and edaphology (how soils interact with living things, especially plants), are used as if synonymous with soil science. The diversity of names associated with this discipline

836-468: Is the study of soil in relation to soil-dependent uses. Both branches apply a combination of soil physics , soil chemistry , and soil biology . Due to the numerous interactions between the biosphere , atmosphere and hydrosphere that are hosted within the pedosphere, more integrated, less soil-centric concepts are also valuable. Many concepts essential to understanding soil come from individuals not identifiable strictly as soil scientists. This highlights

880-619: The Earth's crust ". Academically, soil scientists tend to be drawn to one of five areas of specialization: microbiology , pedology , edaphology , physics , or chemistry . Yet the work specifics are very much dictated by the challenges facing our civilization's desire to sustain the land that supports it, and the distinctions between the sub-disciplines of soil science often blur in the process. Soil science professionals commonly stay current in soil chemistry, soil physics, soil microbiology, pedology, and applied soil science in related disciplines. One exciting effort drawing in soil scientists in

924-496: The U.S. as of 2004 is the Soil Quality Initiative. Central to the Soil Quality Initiative is developing indices of soil health and then monitoring them in a way that gives us long-term (decade-to-decade) feedback on our performance as stewards of the planet. The effort includes understanding the functions of soil microbiotic crusts and exploring the potential to sequester atmospheric carbon in soil organic matter . Relating

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968-438: The atmosphere can transport thermal energy from the higher temperature interior up to the surface. From the perspective of a planetary geologist , the atmosphere acts to shape a planetary surface. Wind picks up dust and other particles which, when they collide with the terrain, erode the relief and leave deposits ( eolian processes). Frost and precipitations , which depend on the atmospheric composition, also influence

1012-411: The base of the exosphere at 690 km and contains the ionosphere , where solar radiation ionizes the atmosphere. The density of the ionosphere is greater at short distances from the planetary surface in the daytime and decreases as the ionosphere rises at night-time, thereby allowing a greater range of radio frequencies to travel greater distances. The exosphere begins at 690 to 1,000 km from

1056-428: The bottom of the mesosphere , and contains the ozone layer , at an altitude between 15 km and 35 km. It is the atmospheric layer that absorbs most of the ultraviolet radiation that Earth receives from the Sun. The mesosphere ranges from 50 km to 85 km and is the layer wherein most meteors are incinerated before reaching the surface. The thermosphere extends from an altitude of 85 km to

1100-407: The breaking down or weathering of rocks". serves to illustrate the historic view of soil which persisted from the 19th century. Dokuchaev's late 19th century soil concept developed in the 20th century to one of soil as earthy material that has been altered by living processes. A corollary concept is that soil without a living component is simply a part of Earth's outer layer. Further refinement of

1144-680: The concept of agriculture to soil quality , however, has not been without its share of controversy and criticism, including critiques by Nobel Laureate Norman Borlaug and World Food Prize Winner Pedro Sanchez . A more traditional role for soil scientists has been to map soils. Almost every area in the United States now has a published soil survey , including interpretive tables on how soil properties support or limit activities and uses. An internationally accepted soil taxonomy allows uniform communication of soil characteristics and soil functions . National and international soil survey efforts have given

1188-426: The diminishing mass of the gas above the point of barometric measurement. The units of air pressure are based upon the standard atmosphere (atm), which is 101,325  Pa (equivalent to 760  Torr or 14.696  psi ). The height at which the atmospheric pressure declines by a factor of e (an irrational number equal to 2.71828) is called the scale height ( H ). For an atmosphere of uniform temperature,

1232-431: The distance from the Sun determines the energy available to heat atmospheric gas to the point where some fraction of its molecules' thermal motion exceed the planet's escape velocity , allowing those to escape a planet's gravitational grasp. Thus, distant and cold Titan , Triton , and Pluto are able to retain their atmospheres despite their relatively low gravities. Since a collection of gas molecules may be moving at

1276-469: The first to identify soil as a resource whose distinctness and complexity deserved to be separated conceptually from geology and crop production and treated as a whole. As a founding father of soil science, Fallou has primacy in time. Fallou was working on the origins of soil before Dokuchaev was born; however Dokuchaev's work was more extensive and is considered to be the more significant to modern soil theory than Fallou's. Previously, soil had been considered

1320-508: The harmful effects of sunlight , ultraviolet radiation, solar wind , and cosmic rays and thus protects the organisms from genetic damage. The current composition of the atmosphere of the Earth is the product of billions of years of biochemical modification of the paleoatmosphere by living organisms. Atmospheres are clouds of gas bound to and engulfing an astronomical focal point of sufficiently dominating mass , adding to its mass, possibly escaping from it or collapsing into it. Because of

1364-442: The hydrogen escaped. Earth's magnetic field helps to prevent this, as, normally, the solar wind would greatly enhance the escape of hydrogen. However, over the past 3 billion years Earth may have lost gases through the magnetic polar regions due to auroral activity, including a net 2% of its atmospheric oxygen. The net effect, taking the most important escape processes into account, is that an intrinsic magnetic field does not protect

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1408-418: The influence of a series of soil-formation factors (climate, vegetation, country, relief and age). According to him, soil should be called the "daily" or outward horizons of rocks regardless of the type; they are changed naturally by the common effect of water, air and various kinds of living and dead organisms. A 1914 encyclopedic definition: "the different forms of earth on the surface of the rocks, formed by

1452-436: The interdisciplinary nature of soil concepts. Exploring the diversity and dynamics of soil continues to yield fresh discoveries and insights. New avenues of soil research are compelled by a need to understand soil in the context of climate change , greenhouse gases , and carbon sequestration . Interest in maintaining the planet's biodiversity and in exploring past cultures has also stimulated renewed interest in achieving

1496-431: The latter, such planetary nucleus can develop from interstellar molecular clouds or protoplanetary disks into rocky astronomical objects with varyingly thick atmospheres, gas giants or fusors . Composition and thickness is originally determined by the stellar nebula's chemistry and temperature, but can also by a product processes within the astronomical body outgasing a different atmosphere. The atmospheres of

1540-406: The past. The circulation of the atmosphere occurs due to thermal differences when convection becomes a more efficient transporter of heat than thermal radiation . On planets where the primary heat source is solar radiation, excess heat in the tropics is transported to higher latitudes. When a planet generates a significant amount of heat internally, such as is the case for Jupiter , convection in

1584-474: The period of time since the initial pedogenesis (soil formation). Using these ideas as a starting point, he developed the very first soil classification . His ideas were quickly taken up by a number of soil scientists, including Hans Jenny . Dokuchaev's work on soil science produced a system of soil classification that described five factors for soil formation . He arrived at his theory after extensive field studies on Russian soils in 1883. His most famous work

1628-429: The planets Venus and Mars are principally composed of carbon dioxide and nitrogen , argon and oxygen . The composition of Earth's atmosphere is determined by the by-products of the life that it sustains. Dry air (mixture of gases) from Earth's atmosphere contains 78.08% nitrogen, 20.95% oxygen, 0.93% argon, 0.04% carbon dioxide, and traces of hydrogen, helium, and other "noble" gases (by volume), but generally

1672-544: The profession unique insights into landscape-scale functions. The landscape functions that soil scientists are called upon to address in the field seem to fall roughly into six areas: There are also practical applications of soil science that might not be apparent from looking at a published soil survey. Depression storage capacity, in soil science, is the ability of a particular area of land to retain water in its pits and depressions, thus preventing it from flowing. Depression storage capacity, along with infiltration capacity ,

1716-416: The relief. Climate changes can influence a planet's geological history. Conversely, studying the surface of the Earth leads to an understanding of the atmosphere and climate of other planets. For a meteorologist , the composition of the Earth's atmosphere is a factor affecting the climate and its variations. For a biologist or paleontologist , the Earth's atmospheric composition is closely dependent on

1760-468: The scale height is proportional to the atmospheric temperature and is inversely proportional to the product of the mean molecular mass of dry air, and the local acceleration of gravity at the point of barometric measurement. Surface gravity differs significantly among the planets. For example, the large gravitational force of the giant planet Jupiter retains light gases such as hydrogen and helium that escape from objects with lower gravity. Secondly,

1804-399: The soil concept is occurring in view of an appreciation of energy transport and transformation within soil. The term is popularly applied to the material on the surface of the Earth's moon and Mars, a usage acceptable within a portion of the scientific community. Accurate to this modern understanding of soil is Nikiforoff's 1959 definition of soil as the "excited skin of the sub aerial part of

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1848-413: The surface, and extends to roughly 10,000 km, where it interacts with the magnetosphere of Earth. Atmospheric pressure is the force (per unit-area) perpendicular to a unit-area of planetary surface, as determined by the weight of the vertical column of atmospheric gases. In said atmospheric model, the atmospheric pressure , the weight of the mass of the gas, decreases at high altitude because of

1892-417: The terrain of rocky planets with atmospheres, and over time can erase the effects of both craters and volcanoes . In addition, since liquids cannot exist without pressure, an atmosphere allows liquid to be present at the surface, resulting in lakes , rivers and oceans . Earth and Titan are known to have liquids at their surface and terrain on the planet suggests that Mars had liquid on its surface in

1936-461: Was determined is HD 209458b , a gas giant with a close orbit around a star in the constellation Pegasus . Its atmosphere is heated to temperatures over 1,000 K, and is steadily escaping into space. Hydrogen, oxygen, carbon and sulfur have been detected in the planet's inflated atmosphere. The atmosphere of Earth is composed of layers with different properties, such as specific gaseous composition, temperature, and pressure. The troposphere

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