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:
Other forms of lime have common applications in agriculture and gardening, including dolomitic lime and hydrated lime. Dolomitic lime may be used as a soil input to provide similar effects as agricultural lime, while supplying magnesium in addition to calcium. In livestock farming, hydrated lime can be used as a disinfectant measure, producing a dry and alkaline environment in which bacteria do not readily multiply. In horticultural farming it can be used as an insect repellent, without causing harm to the pest or plant.
Spinner-style lime spreaders are generally used to spread agricultural lime on fields.
Agricultural lime is injected into coal burners at power plants to reduce the pollutants such as NO2 and SO2 from the emissions.
Lime can improve crop yield and the root system of plants and grass where soils are acidic. It does this by making the soil more basic, allowing the plants to absorb more nutrients. Lime is not a fertilizer but can be used in combination with fertilizers. [3] [4]
Soils become acidic in several ways. Locations that have high rainfall levels become acidic through leaching. Land used for crop and livestock purposes loses minerals over time by crop removal and becomes acidic. [5] The application of modern chemical fertilizers is a major contributor to soil acid by the process in which the plant nutrients react in the soil. [6]
Aglime can also benefit soils where the land is used for breeding and raising foraging animals. Bone growth is key to a young animal's development, and bones are composed primarily of calcium and phosphorus. [7] Young mammals get their needed calcium through milk, which has calcium as one of its major components. Dairymen frequently apply aglime because it increases milk production.
The best way to determine if the soil is acidic or deficient in calcium or magnesium is with a soil test which a university can provide with an agricultural education department for under $30.00 for United States residents. [8] Farmers typically become interested in soil testing when they notice a decrease in crop response to applied fertilizer.
"Corrected lime potential" [9] is used in soil testing laboratories to indicate whether lime is required. [10]
The quality of agricultural limestone is determined by the chemical makeup of the limestone and how finely the stone is ground. To aid the farmer in determining the relative value of competing agricultural liming materials, the agricultural extension services of several universities use two rating systems. [11] Calcium Carbonate Equivalent (CCE) and the Effective Calcium Carbonate Equivalent (ECCE) give a numeric value to the effectiveness of different liming materials.
The CCE compares the chemistry of a particular quarry's stone with the neutralizing power of pure calcium carbonate. Because each molecule of magnesium carbonate is lighter than calcium carbonate, limestones containing magnesium carbonate (dolomite) can have a CCE greater than 100 percent. [12]
Because the acids in soil are relatively weak, agricultural limestones must be ground to a small particle size to be effective. The extension service of different states rate the effectiveness of stone size particles slightly differently. [13] They all agree, however, that the smaller the particle size the more effective the stone is at reacting in the soil. [14] Measuring the size of particles is based on the size of a mesh that the limestone would pass through. The mesh size is the number of wires per inch. [15] Stone retained on an 8 mesh will be about the size of BB pellets. Material passing a 60 mesh screen will have the appearance of face powder. Particles larger than 8 mesh are of little or no value, particles between 8 mesh and 60 mesh are somewhat effective and particles smaller than 60 mesh are 100 percent effective.
By combining the chemistry of a particular product (CCE) and its particle size the Effective Calcium Carbonate Equivalent (ECCE) is determined. The ECCE is percentage comparison of a particular agricultural limestone with pure calcium carbonate with all particles smaller than 60 mesh. Typically the aglime materials in commercial use will have ECCE ranging from 45 percent to 110 percent.
Brazil's vast inland cerrado region was regarded as unfit for farming before the 1960s because the soil was too acidic and poor in nutrients, according to Nobel Peace Prize winner Norman Borlaug, an American plant scientist referred to as the father of the Green Revolution. However, from the 1960s, vast quantities of lime (pulverised chalk or limestone) were poured into the soil to reduce acidity. The effort continued, and in the late 1990s, between 14 million and 16 million tonnes of lime were spread on Brazilian fields each year. The quantity rose to 25 million tonnes in 2003 and 2004, equalling around five tonnes of lime per hectare. As a result, Brazil has become the world's second biggest soybean exporter, and thanks to the boom in animal feed production, Brazil is now the biggest exporter of beef and poultry in the world. [16]
A 2019 study demonstrated that agricultural lime affects strontium-based mobility studies, which attempt to identify where individual prehistoric people lived. [17] Agricultural lime has a significant effect in areas with calcium-poor soils. In a systematic study of a river system in Denmark, the Karup River, more than half of the strontium in the river's catchment area was found to come from runoff of agricultural lime, and not from the surrounding natural environment. Such introduction of agricultural lime has resulted in researchers wrongly concluding that certain prehistoric individuals originated far abroad from their burial sites, because strontium isotopic results measured in their remains and personal effects were compared to burial sites contaminated by agricultural lime. [18] [19]
Limestone is a common type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate. Limestone forms when these minerals precipitate out of water containing dissolved calcium. This can take place through both biological and nonbiological processes, though biological processes, such as the accumulation of corals and shells in the sea, have likely been more important for the last 540 million years. Limestone often contains fossils, and these provide scientists with information on ancient environments and on the evolution of life.
Marl is an earthy material rich in carbonate minerals, clays, and silt. When hardened into rock, this becomes marlstone. It is formed in marine or freshwater environments, often through the activities of algae.
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 in a solution. In soils, it is measured in a slurry of soil mixed with water, 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 and very strongly alkaline soils are rare.
Plant nutrition is the study of the chemical elements and compounds necessary for plant growth and reproduction, plant metabolism and their external supply. In its absence the plant is unable to complete a normal life cycle, or that the element is part of some essential plant constituent or metabolite. This is in accordance with Justus von Liebig’s law of the minimum. The total essential plant nutrients include seventeen different elements: carbon, oxygen and hydrogen which are absorbed from the air, whereas other nutrients including nitrogen are typically obtained from the soil.
Rock flour, or glacial flour, consists of fine-grained, silt-sized particles of rock, generated by mechanical grinding of bedrock by glacial erosion or by artificial grinding to a similar size. Because the material is very small, it becomes suspended in meltwater making the water appear cloudy, which is sometimes known as glacial milk.
Liming is the application of calcium- (Ca) and magnesium (Mg)-rich materials in various forms, including marl, chalk, limestone, burnt lime or hydrated lime. In acid soils, these materials react as a base and neutralize soil acidity. This often improves plant growth and increases the activity of soil bacteria, but oversupply may result in harm to plant life.
Phosphorite, phosphate rock or rock phosphate is a non-detrital sedimentary rock that contains high amounts of phosphate minerals. The phosphate content of phosphorite (or grade of phosphate rock) varies greatly, from 4% to 20% phosphorus pentoxide (P2O5). Marketed phosphate rock is enriched ("beneficiated") to at least 28%, often more than 30% P2O5. This occurs through washing, screening, de-liming, magnetic separation or flotation. By comparison, the average phosphorus content of sedimentary rocks is less than 0.2%. The phosphate is present as fluorapatite Ca5(PO4)3F typically in cryptocrystalline masses (grain sizes < 1 μm) referred to as collophane-sedimentary apatite deposits of uncertain origin. It is also present as hydroxyapatite Ca5(PO4)3OH or Ca10(PO4)6(OH)2, which is often dissolved from vertebrate bones and teeth, whereas fluorapatite can originate from hydrothermal veins. Other sources also include chemically dissolved phosphate minerals from igneous and metamorphic rocks. Phosphorite deposits often occur in extensive layers, which cumulatively cover tens of thousands of square kilometres of the Earth's crust.
Lime is a calcium-containing inorganic material composed primarily of oxides and hydroxide, usually calcium oxide and/or calcium hydroxide. It is also the name for calcium oxide which occurs as a product of coal-seam fires and in altered limestone xenoliths in volcanic ejecta. The International Mineralogical Association recognizes lime as a mineral with the chemical formula of CaO. The word lime originates with its earliest use as building mortar and has the sense of sticking or adhering.
A soil conditioner is a product which is added to soil to improve the soil’s physical qualities, usually its fertility and sometimes its mechanics. In general usage, the term "soil conditioner" is often thought of as a subset of the category soil amendments, which more often is understood to include a wide range of fertilizers and non-organic materials.
Organic fertilizers are fertilizers that are naturally produced. Fertilizers are materials that can be added to soil or plants, in order to provide nutrients and sustain growth. Typical organic fertilizers include all animal waste including meat processing waste, manure, slurry, and guano; plus plant based fertilizers such as compost; and biosolids. Inorganic "organic fertilizers" include minerals and ash. The organic-ness refers to the Principles of Organic Agriculture, which determines whether a fertilizer can be used for commercial organic agriculture, not whether the fertilizer consists of organic compounds.
Bone meal is a mixture of finely and coarsely ground animal bones and slaughter-house waste products. It is used as a dietary supplement to supply calcium (Ca) and phosphorus (P) to monogastric livestock in the form of hydroxiapathite. As a slow-release organic fertilizer, it supplies Phosphorus, Calcium, and a small amount of Nitrogen to plants.
Calcareous is an adjective meaning "mostly or partly composed of calcium carbonate", in other words, containing lime or being chalky. The term is used in a wide variety of scientific disciplines.
Agrogeology is the study of the origins of minerals known as agrominerals and their applications. These minerals are of importance to farming and horticulture, especially with regard to soil fertility and fertilizer components. These minerals are usually essential plant nutrients. Agrogeology can also be defined as the application of geology to problems in agriculture, particularly in reference to soil productivity and health. This field is a combination of a few different fields, including geology, soil science, agronomy, and chemistry. The overall objective is to advance agricultural production by using geological resources to improve chemical and physical aspects of soil.
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 biodiversity refers to the relationship of soil to biodiversity and to aspects of the soil that can be managed in relation to biodiversity. Soil biodiversity relates to some catchment management considerations.
Crushed stone or angular rock is a form of construction aggregate, typically produced by mining a suitable rock deposit and breaking the removed rock down to the desired size using crushers. It is distinct from naturally occurring gravel, which is produced by natural processes of weathering and erosion and typically has a more rounded shape.
The Michigan Limestone and Chemical Company operates the world's largest limestone quarry, which is located near Rogers City, Michigan. It was formed and organized in 1910; however, production did not begin until 1912. Ownership of the quarry has changed a number of times, but it is still one of the country's largest producers of limestone.
William Albert Albrecht chairman of the Department of Soils at the University of Missouri, was the foremost authority on the relation of soil fertility to human health and earned four degrees from the University of Illinois at Urbana–Champaign. As emeritus professor of soils at the University of Missouri, he saw a direct link between soil quality, food quality and human health. He drew direct connections between poor quality forage crops, and ill health in livestock and from this developed a formula for ideal ratios of cations in the soil, the Base Cation Saturation Ratio. While he did not discover cation exchange in the soil as is sometimes supposed, he may have been the first to associate it with colloidal clay particles. He served as 1939 President of the Soil Science Society of America.
Twenty years before the phrase 'environmental concern' crept into the national consciousness, he was lecturing from coast to coast on the broad topic of agricultural ecology.
" The soil is the ‘creative material’ of most of the basic needs of life. Creation starts with a handful of dust.” Dr. William A. Abrecht.
The calcium cycle is a transfer of calcium between dissolved and solid phases. There is a continuous supply of calcium ions into waterways from rocks, organisms, and soils. Calcium ions are consumed and removed from aqueous environments as they react to form insoluble structures such as calcium carbonate and calcium silicate, which can deposit to form sediments or the exoskeletons of organisms. Calcium ions can also be utilized biologically, as calcium is essential to biological functions such as the production of bones and teeth or cellular function. The calcium cycle is a common thread between terrestrial, marine, geological, and biological processes. Calcium moves through these different media as it cycles throughout the Earth. The marine calcium cycle is affected by changing atmospheric carbon dioxide due to ocean acidification.