Illinois Soil Nitrogen Test

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The Illinois Soil Nitrogen Test ("ISNT") is a method for measuring the amount of Nitrogen in soil that is available for use by plants as a nutrient. The test predicts whether the addition of nitrogen fertilizer to agricultural land will result in increased crop yields. [1] [2]

Nitrogen Chemical element with atomic number 7

Nitrogen is the chemical element with the symbol N and atomic number 7. It was first discovered and isolated by Scottish physician Daniel Rutherford in 1772. Although Carl Wilhelm Scheele and Henry Cavendish had independently done so at about the same time, Rutherford is generally accorded the credit because his work was published first. The name nitrogène was suggested by French chemist Jean-Antoine-Claude Chaptal in 1790, when it was found that nitrogen was present in nitric acid and nitrates. Antoine Lavoisier suggested instead the name azote, from the Greek ἀζωτικός "no life", as it is an asphyxiant gas; this name is instead used in many languages, such as French, Russian, Romanian and Turkish, and appears in the English names of some nitrogen compounds such as hydrazine, azides and azo compounds.

Soil mixture of organic matter, minerals, gases, liquids, and organisms that together support life

Soil is a mixture of organic matter, minerals, gases, liquids, and organisms that together support life. Earth's body of soil, called the pedosphere, has four important functions:

Fertilizer Substance added to soils to supply plant nutrients for a better growth

A fertilizer or fertiliser is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply one or more plant nutrients essential to the growth of plants. Many sources of fertilizer exist, both natural and industrially produced.

Nitrogen is essential for plant development. Indeed, for crops that are destined to be food for farm animal or human consumption, incorporation of nitrogen into the crop is an important goal, since this forms the basis for protein in the human diet.

Protein Biological molecule consisting of chains of amino acid residues

Proteins are large biomolecules, or macromolecules, consisting of one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, providing structure to cells and organisms, and transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the nucleotide sequence of their genes, and which usually results in protein folding into a specific three-dimensional structure that determines its activity.

Nitrogen is commonly present in soils in many forms, and there are many ways to measure this nitrogen. None of these are completely satisfactory as a measure of the nitrogen that is available for use by crops. The ISNT is a new (2007) method for measuring nitrogen available for plant uptake.

ISNT estimates the amount of nitrogen present in the soil as amino sugar nitrogen. With respect to corn and soybeans, the optimal range for plant growth appears to be around 225 to 240 mg/Kg. Some form of nitrogen fertilizer is needed if levels are below this range. On the other hand, if levels are above this range, addition of nitrogen fertilizer will not increase crop yield.

Carbohydrate Organic compound that consists only of carbon, hydrogen, and oxygen

A carbohydrate is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in water) and thus with the empirical formula Cm(H2O)n (where m may be different from n). This formula holds true for monosaccharides. Some exceptions exist; for example, deoxyribose, a sugar component of DNA, has the empirical formula C5H10O4. The carbohydrates are technically hydrates of carbon; structurally it is more accurate to view them as aldoses and ketoses.

Maize Cereal grain

Maize, also known as corn, is a cereal grain first domesticated by indigenous peoples in southern Mexico about 10,000 years ago. The leafy stalk of the plant produces pollen inflorescences and separate ovuliferous inflorescences called ears that yield kernels or seeds, which are fruits.

Soybean legume grown for its edible bean with many uses

The soybean or soya bean is a species of legume native to East Asia, widely grown for its edible bean, which has numerous uses.

In the corn belt, since about 1975, the predominant method of estimating the amount of nitrogen needed for corn has been the "yield-based" method. A farmer first estimates the yield of corn he intends to produce. He then applies 1.1 to 1.4 lbs of nitrogen per bushel of expected yield. [3] ISNT represents an alternative approach to managing nitrogen application. However, ISNT does not offer a simple answer as to the amount of nitrogen fertilizer that is needed, or as to the optimal form of that fertilizer.

In field trials in Illinois, some fields have been found to be under-fertilized when managed according to the "yield-based" method, as judged by the ISNT. In the majority of trials, however, the yield-based method calls for the addition of nitrogen far in excess of the levels needed for optimal crop production. This nitrogen, which is applied by farmers at great cost, does not find its way into the crop, but is lost to the atmosphere or leaches into waterways.

Within the corn belt, stalks and other crop residues are left in the field with the intention of enhancing the amount of organic material in the soil. Excessive nitrogen application, however, appears to promote the rapid decomposition of organic matter in the soil, resulting in release of carbon dioxide. [4] As a result, the amount of organic material in soils managed according to the yield-based method in the corn belt appears to be decreasing in spite of the large amounts of crop residues left in the fields.

Carbon dioxide chemical compound

Carbon dioxide is a colorless gas with a density about 60% higher than that of dry air. Carbon dioxide consists of a carbon atom covalently double bonded to two oxygen atoms. It occurs naturally in Earth's atmosphere as a trace gas. The current concentration is about 0.04% (410 ppm) by volume, having risen from pre-industrial levels of 280 ppm. Natural sources include volcanoes, hot springs and geysers, and it is freed from carbonate rocks by dissolution in water and acids. Because carbon dioxide is soluble in water, it occurs naturally in groundwater, rivers and lakes, ice caps, glaciers and seawater. It is present in deposits of petroleum and natural gas. Carbon dioxide is odorless at normally encountered concentrations, but at high concentrations, it has a sharp and acidic odor.

See also

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Crop rotation practice of growing a series of dissimilar or different types of crops in the same area in sequenced seasons

Crop rotation is the practice of growing a series of dissimilar or different types of crops in the same area in sequenced seasons. It is done so that the soil of farms is not used for only one set of nutrients. It helps in reducing soil erosion and increases soil fertility and crop yield.

Precision agriculture

Precision agriculture (PA), satellite farming or site specific crop management (SSCM) is a farming management concept based on observing, measuring and responding to inter and intra-field variability in crops. The goal of precision agriculture research is to define a decision support system (DSS) for whole farm management with the goal of optimizing returns on inputs while preserving resources.

In agriculture, green manure is created by leaving uprooted or sown crop parts to wither on a field so that they serve as a mulch and soil amendment. The plants used for green manure are often cover crops grown primarily for this purpose. Typically, they are ploughed under and incorporated into the soil while green or shortly after flowering. Green manure is commonly associated with organic farming and can play an important role in sustainable annual cropping systems.

Cover crop crop planted to manage erosion and soil quality

A cover crop is planted to manage soil erosion, soil fertility, soil quality, water, weeds, pests, diseases, biodiversity and wildlife in an agroecosystem—an ecological system managed and shaped by humans. Cover crops may be an off-season crop planted after harvesting the cash crop. The cover crop may grow over winter.

No-till farming agricultural method which does not disturb soil through tillage.

No-till farming is a way of growing crops or pasture from year to year without disturbing the soil through tillage. No-till is an agricultural technique that increases the amount of water that infiltrates into the soil, the soil's retention of organic matter and its cycling of nutrients. In many agricultural regions, it can reduce or eliminate soil erosion. It increases the amount and variety of life in and on the soil, including disease-causing organisms and disease organisms. The most powerful benefit of no-tillage is improvement in soil biological fertility, making soils more resilient. Farm operations are made much more efficient, particularly improved time of sowing and better trafficability of farm operations.

Nutrient management

Nutrient management is the science and practice directed to link soil, crop, weather, and hydrologic factors with cultural, irrigation, and soil and water conservation practices to achieve optimal nutrient use efficiency, crop yields, crop quality, and economic returns, while reducing off-site transport of nutrients (fertilizer) that may impact the environment. It involves matching a specific field soil, climate, and crop management conditions to rate, source, timing, and place of nutrient application.

Soil fertility Ability of a soil to sustain agricultural plant growth

Soil fertility refers to the ability of soil to sustain agricultural plant growth, i.e. to provide plant habitat and result in sustained and consistent yields of high quality. A fertile soil has the following properties:

Living mulch

In agriculture, a living mulch is a cover crop interplanted or undersown with a main crop, and intended to serve the purposes of a mulch, such as weed suppression and regulation of soil temperature. Living mulches grow for a long time with the main crops, whereas cover crops are incorporated into the soil or killed with herbicides.

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.

Fertigation

Fertigation is the injection of fertilizers, used for soil amendments, water amendments and other water-soluble products into an irrigation system.

Intensive crop farming

Intensive crop farming is a modern form of farming that refers to the industrialized production of crops. Intensive crop farming's methods include innovation in agricultural machinery, farming methods, genetic engineering technology, techniques for achieving economies of scale in production, the creation of new markets for consumption, patent protection of genetic information, and global trade. These methods are widespread in developed nations.

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.

Soil management is the application of operations, practices, and treatments to protect soil and enhance its performance. It includes soil conservation, soil amendment, and optimal soil health. In agriculture, some amount of soil management is needed both in nonorganic and organic types to prevent agricultural land from becoming poorly productive over decades. Organic farming in particular emphasizes optimal soil management, because it uses soil health as the exclusive or nearly exclusive source of its fertilization and pest control.

Base-cation saturation ratio

Base-cation saturation ratio (BCSR) is a method of interpreting soil test results that is widely used in sustainable agriculture, supported by the National Sustainable Agriculture Information Service (ATTRA) and claimed to be successfully in use on over a million acres (4,000 km²) of farmland worldwide. The traditional method, as used by most university laboratories, is known variously as the 'sufficiency level', sufficiency level of available nutrients (SLAN), or Index(UK) system. The sufficiency level system is concerned only with keeping plant-available nutrient levels within a well studied range, making sure there is neither a deficiency nor an excess. In the BCSR system, soil cations are balanced according to varying ratios often stated as giving 'ideal' or 'balanced' soil. These ratios can be between individual cations, such as the calcium to magnesium ratio, or they may be expressed as a percentage saturation of the cation exchange capacity (CEC) of the soil. Most 'ideal soil' theories stress both approaches.

William Albrecht agronomist

William A. Albrecht (1888–1974) PhD, 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. 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 nutrient content of a plant can be assessed by testing a sample of tissue from that plant. These tests are important in agriculture since fertilizer application can be fine-tuned if the plants nutrient status is known. Nitrogen most commonly limits plant growth and is the most managed nutrient.

CULTAN Fertilization, or Controlled Uptake Long Term Ammonium Nutrition, is a type of injection fertilization where the entire amount of nitrogen needed for a plant to grow is injected at one time. During CULTAN fertilization, nitrogen is applied at the first signs of nitrogen deficiency in plants. Fertilizer is more commonly spread on the surface of fields in either a liquid or powder form by spraying it.

Organic hydroponics is a hydroponics culture system which is managed based on organic agriculture concepts. Most studies have focused on use of organic fertilizer. Conventional hydroponics have a difficult time using organic compounds as fertilizer.

Reuse of excreta Safe, beneficial use of animal or human excreta

Reuse of excreta refers to the safe, beneficial use of animal or human excreta, i.e. faeces and urine. Such beneficial use involves mainly the nutrient, organic matter and energy contained in excreta, rather than the water content. Reuse of excreta can involve using it as soil conditioner or fertilizer in agriculture, gardening, aquaculture or horticultural activities. Excreta can also be used as a fuel source or as a building material.

References

  1. ↑ Need for a Soil-Based Approach in Managing Nitrogen Fertilizers for Profitable Corn Production, R.L. Mulvaney, S.A. Khan, T.R. Ellsworth, Soil Sci. Soc. Am. J. 70:172-182 (2006)
  2. ↑ Illinois Soil Nitrogen Test Predicts Southeastern U.S. Corn Economic Optimum Nitrogen Rates, Jared D. Williams et al., Soil Sci Soc Am J 71:735-744 (2007) "Archived copy". Archived from the original on 2008-06-21. Retrieved 2009-09-14.CS1 maint: archived copy as title (link)
  3. ↑ Need for a Soil-Based Approach in Managing Nitrogen Fertilizers for Profitable Corn Production, R.L. Mulvaney, S.A. Khan, T.R. Ellsworth, Soil Sci. Soc. Am. J. 70:172-182 (2006)
  4. ↑ The Myth of Nitrogen Fertilization for Soil Carbon Sequestration, S.A. Khan, R.L. Mulvaney et al., J. Environ. Qual. 36:1821-1832 (2007)
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