Soil pH in the context of "Agrochemical"

⭐ In the context of Agrochemicals, modifying Soil_pH is achieved through the application of substances like…

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⭐ Core Definition: Soil pH

Soil pH is a measure of the acidity or basicity (alkalinity) of a soil. Soil pH is a key characteristic that can be used to make informative analysis both qualitative and quantitatively regarding soil characteristics. pH is defined as the negative logarithm (base 10) of the activity of hydronium ions (H
or, more precisely, H
3
O
aq
) in a solution. In soils, it is measured in a slurry of soil mixed with water (or a salt solution, such as 0.01 M CaCl
2
), and normally falls between 3 and 10, with 7 being neutral. Acid soils have a pH below 7 and alkaline soils have a pH above 7. Ultra-acidic soils (pH < 3.5) and very strongly alkaline soils (pH > 9) are rare.

Soil pH is considered a master variable in soils as it affects many chemical processes. It specifically affects plant nutrient availability by controlling the chemical forms of the different nutrients and influencing the chemical reactions they undergo. The optimum pH range for most plants is between 5.5 and 7.5; however, many plants have adapted to thrive at pH values outside this range.

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👉 Soil pH in the context of Agrochemical

An agrochemical or agrichemical, a contraction of agricultural chemical, is a chemical product used in conventional or industrial agriculture. Agrochemical typically refers to pesticides and synthetic fertilizers. The term agrochemical is sometimes used informally synonymously with pesticides, sometimes also informally to mean pesticides and fertilizers, and sometimes more correctly to include all chemicals used in agriculture. Other chemicals used in agriculture are plant hormones and plant growth regulators (PGRs), insect attractants, insect repellents, plant defense inducers, herbicide safeners, adjuvents and co-formulants, soil conditioners and soil amendments, liming and acidifying agents. For livestock feed additives, animal growth regulators, anthelmintics and other antiparasitics are used.

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In this Dossier

Soil pH in the context of Agricultural lime

Agricultural lime, also called aglime, agricultural limestone, garden lime or liming, is a soil additive made from pulverized limestone or chalk. The primary active component is calcium carbonate. Additional chemicals vary depending on the mineral source and may include calcium oxide. Unlike the types of lime called quicklime (calcium oxide) and slaked lime (calcium hydroxide), powdered limestone does not require lime burning in a lime kiln; it only requires milling. All of these types of lime are sometimes used as soil conditioners, with a common theme of providing a base to correct acidity, but lime for farm fields today is often crushed limestone. Historically, liming of farm fields in centuries past was often done with burnt lime; the difference is at least partially explained by the fact that affordable mass-production-scale fine milling of stone and ore relies on technologies developed since the mid-19th century.

Some effects of agricultural lime on soil are:

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Soil pH in the context of Alkali soil

Alkali, or alkaline, soils are clay soils with high pH (greater than 8.5), a poor soil structure and a low infiltration capacity. Often they have a hard calcareous layer at 0.5 to 1 metre depth. Alkali soils owe their unfavorable physico-chemical properties mainly to the dominating presence of sodium carbonate, which causes the soil to swell and to be difficult to clarify/settle. They derive their name from the alkali metal group of elements, to which sodium belongs, and which can induce basicity. Sometimes these soils are also referred to as alkaline sodic soils. Alkaline soils are basic, but not all basic soils are alkaline.

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Soil pH in the context of Moorland

Moorland or moor is a type of habitat found in upland areas in temperate grasslands, savannas, and shrublands and the biomes of montane grasslands and shrublands, characterised by low-growing vegetation on acidic soils. Moorland today generally means uncultivated hill land (such as Dartmoor in South West England), but also includes low-lying wetlands (such as Sedgemoor, also South West England). It is closely related to heath, although experts disagree on the exact distinction between these types of vegetation. Generally, moor refers to highland and high rainfall areas, while heath refers to lowland zones which are more likely to be the result of human activity.

Moorland habitats are found mainly in tropical Africa, northern and western Europe, and South America. Most of the world's moorlands are diverse ecosystems. In the extensive moorlands of the tropics, biodiversity can be extremely high. Moorland is also related to tundra (where the subsoil is permafrost or permanently frozen soil), appearing as the tundra and the natural tree zone. The boundary between tundra and moorland constantly shifts with climatic change.

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Soil pH in the context of Drought tolerance in barley

Barley (Hordeum vulgare) is known to be more environmentally-tolerant than other cereal crops, in terms of soil pH, mineral nutrient availability, and water availability. Because of this, much research is being done on barley plants in order to determine whether or not there is a genetic basis for this environmental hardiness.

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Soil pH in the context of Soil acidification

Soil acidification is the buildup of hydrogen cations, which reduces the soil pH. Chemically, this happens when a proton donor gets added to the soil. The donor can be an acid, such as nitric acid, sulfuric acid, or carbonic acid. It can also be a compound such as aluminium sulfate, which reacts in the soil to release protons. Acidification also occurs when base cations such as calcium, magnesium, potassium and sodium are leached from the soil.

Soil acidification naturally occurs as lichens and algae begin to break down rock surfaces. Acids continue with this dissolution as soil develops. With time and weathering, soils become more acidic in natural ecosystems. Soil acidification rates can vary, and increase with certain factors such as acid rain, agriculture, and pollution.

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Soil pH in the context of Soil map

A soil map is a geographical representation showing diversity of soil types or soil properties (soil pH, textures, organic matter, depths of horizons etc.) in the area of interest. It is typically the result of a soil survey inventory, i.e. soil survey. Soil maps are most commonly used for land evaluation, spatial planning, agricultural extension, environmental protection and similar projects. Traditional soil maps typically show only general distribution of soils, accompanied by the soil survey report. Many new soil maps are derived using digital soil mapping techniques. Such maps are typically richer in context and show higher spatial detail, yet are not necessarily more accurate than traditional soil maps. Soil maps produced using (geo)statistical technique can also include an estimate of the model uncertainty.

In the digital era, soil maps come in various digital vector and raster formats and are used for various applications in geosciences and environmental sciences. In this context, soil maps are only visualizations of the soil resource inventories commonly stored in a Soil Information System (SIS), of which the major part is a Soil Geographical Database. A Soil Information System is basically a systematic collection of complete (values of the target soil variables available for the whole area of interest) and consistent gridded or vector soil property and/or class maps with an attached report, user manual and/or metadata. A SIS is in the most cases, a combination of polygon and point maps linked with attribute tables for profile observations, soil mapping units and soil classes. Different elements of an SIS can be manipulated and then visualized against the spatial reference (grids or polygons). For example, soil profiles can be used to make spatial prediction of different chemical and physical soil properties. In the case of pedometric mapping, both predictions and simulations (2D or 3D — geographic location plus soil depth) of values are visualized and used for GIS modeling.

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Soil pH in the context of Pedunculate oak

Quercus robur, the pedunculate (or "English") oak, is a species of flowering plant in the beech and oak family, Fagaceae. It is a large tree, native to most of Europe and western Asia, and is widely cultivated in other temperate regions. It grows on soils of near neutral acidity in the lowlands and is notable for its value to natural ecosystems, supporting a very wide diversity of herbivorous insects and other pests, predators and pathogens.

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