Nitrogen cycle

12 Key excerpts on "Nitrogen cycle"

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  Global biogeochemical cycles

  • Butcher(Author)
  • 1992(Publication Date)
  • Academic Press

    (Publisher)

  12 The Nitrogen cycle Daniel A. Jaffe 12.1 Introduction The Nitrogen cycle offers a rich variety of important biological and abiotic processes that involve many important compounds in the gas, liquid, and solid phases. Compounds of nitrogen also play important roles in a wide range of contemporary environmental issues, from the perturbation of stratospheric ozone to the contamination of groundwater. Global nitro-gen cycles also offer some very interesting puzzles. Why does the Earth have a predominantly nitrogen atmosphere? What factors are responsible for the striking increase in atmospheric nitrous oxide? There are several reasons for trying to come to grips with the Nitrogen cycle. First, much nitrogen is coupled with other elements of living matter -C, S, and P. Understanding nitrogen will help us understand the role of living matter in bio-geochemical cycles. Second, nitrogen is implicated in several of the ways humankind impacts the natural environment. Photochemical smog, acid precipi-tation, and nitrate pollution of groundwater are all related to compounds of nitrogen. Ammonia plays an important role in atmospheric aerosols and may have been a significant greenhouse gas in the early atmosphere. In this chapter, we will look at the parts of the Nitrogen cycle, and then integrate these parts into a single comprehensive view of the Nitrogen cycle. The first step in this process is to take a look at the many varied nitrogen compounds that exist in natural systems. We then consider the biological processes that transform nitrogen. Next, we will consider abiotic transformations (mainly inorganic reactions occurring in the atmosphere). We can then consider the physical processes that serve to transport nitrogen from one reservoir to another; for example the process by which N 20 reaches the stratosphere, or NH 3 is volatilized from decomposing organic matter. 12.2 Chemistry Nitrogen has five valence electrons and can take on oxidation states between +5 and -3.

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  Structure and Functioning of Seminatural Meadows

  • M. Rychnovská(Author)
  • 2012(Publication Date)
  • Elsevier Science

    (Publisher)

  16 THE Nitrogen cycle Nitrogen is indispensable for all forms of life. The greatest reservoir of nitrogen is the atmosphere. While the C 0 2 concentration in the air is 0 . 0 3 % that of nitrogen is about 7 9 % . However, only a small part of this large nitrogen pool enters into ecosystems. Only a few groups of micro-organisms are able to trans-form gaseous atmospheric nitrogen at first into organic and then into mineral nitrogenous substances. The micro-organisms also mediate most of the decom-position and transformation processes taking place in the soil which involve nitrogenous substances; thus they have a key position in nitrogen cycling. During recent decades, the Nitrogen cycle has become distinctly affected by industrial and agricultural activities of m a n and by his extensive use of road vehicles on the local, regional and global levels. The industrialized type of agriculture increases nitrogen inputs into the biosphere through the application of mineral fertilizers. Concurrently, the amounts of nitrates percolating into the groundwater and watercourses increase on both local and regional scales, and so do the losses of nitrogen to the atmosphere; the turnover of nitrogen in the biosphere is becoming more intensive. The growth of industry is associated with a high output of acidic emissions to the atmosphere. The emitted gasses of the N O x and S O x type are stripped from the air back to the earth by rain. Acid rain adversely affects both biotic and abiotic components of ecosystems. It retards the production of trees on a global scale, and often they eventually die off over large areas. Some of the biotic components of ecosystems can be similarly eliminated from trophic chains on a local scale. Some of the nitrogen oxides escape to the stratosphere, contributing to the destruction of the ozone layer which protects the Earth from excessive ultraviolet radiation.

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  Encyclopedia of Environmental Science Vol1

  Ecological Concepts and Environmental Science

  • Shalinee Naidoo(Author)
  • 2019(Publication Date)
  • Delve Publishing

    (Publisher)

  From here, it is taken in by the bodies of animals before being broken down and released as a waste product. Nitrogenous compounds from dead organisms and their waste excreta are subsequently converted into ammonia by bacteria. From here it is then converted into nitrates and nitrites, of which nitrates are subsequently converted back into nitrogen gas by denitrifying bacteria. Figure 38: Overview of prokaryote activity in the Nitrogen cycle (Adapted from Mills, 1987). 20.7. PROCESSES IN THE Nitrogen cycle There are five main processes within the Nitrogen cycle that allow nitrogen to cycle through the biosphere, atmosphere and geosphere. These include nitrogen fixation, nitrogen uptake, nitrogen mineralization, nitrification and denitrification. In order for these processes to take place, microorganisms that can carry out the nitrogen transformations need to be present and their rate of activity is often influenced by changing environmental factors like temperature, moisture and availability (Figure 39). Ecological Concepts and Environmental Science 131 Figure 39: Overview of the Nitrogen cycle. 20.8. NITROGEN FIXATION This is the process whereby nitrogen is converted to ammonia or ammonium directly from the atmosphere by a range of terrestrial and aquatic microorganisms. Certain species of bacteria such as those found among the Rhizobium genus are known to be able to convert nitrogen gas to ammonia and often form symbiotic relationships with host plants such as those found in the legume family of plants like beans, and peas. The presence of a symbiotic relationship means that both the bacteria and plants will benefit from this relationship. The bacteria are usually found in the root nodules of the plant wherein they are able to utilize the plant’s stored food. This provides the bacteria with the energy they require to carry out nitrogen fixation while on the other hand, the legume plants benefit as a result of excess ammonia being present.

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  March of the Microbes

  Sighting the Unseen

  • John L. Ingraham(Author)
  • 2010(Publication Date)
  • Belknap Press

    (Publisher)

  One wonders why. We do not have a compelling answer, but, indeed, only they can do it. We have suggested that the flow of nitrogen from the atmosphere through plants and animals and back again to the atmosphere is a cyclic process. In fact, the flow is a bit more complex; it consists of a set of cycles. Collectively, these cyclic conversions constitute the Nitrogen cycle. In addition to nitrogen fixation, three other essential steps in the cycle (ammonia to nitrite, nitrite to nitrate, fixed to gas-eous nitrogen) are also totally dependent on prokaryotic microbes. Cycling Nitrogen 121 The cycle would cease were there gaps anywhere in it. We will en-counter these steps throughout the book. Other bioelements, including carbon, oxygen, sulfur, and phos-phorus, undergo similar sorts of cyclic conversions in nature. They, too, are essential for life. All these “cycles of matter” are poster children for microbes’ many essential roles in keeping planetary ecology reasonably intact. The inconspicuous swellings on the sweet pea’s roots are a small but important part of a much grander tableau, the massive set of microbe-mediated conversions on which all life depends. Next we will encounter a completely different nitrogen-fixing symbiosis of microbes and plants. Dark Blue-Green Spots on Liverworts Careful examination of damp places in nature, perhaps a drippy, roadside embankment or streamside tree trunk, frequently reveals atmospheric nitrogen gas m i c r o b i a l l i gh t n i n g , f i r e s , e t c . i n d u s t r i a l ammonia nitrite nitrate bacteria bacteria b a c t e r i a a n a m m o x ( b a c t er i a) d e n i t r i f i c a t i o n ( p r o k a ry o t es ) The Nitrogen cycle. 122 March of the Microbes the presence of liverworts or hornworts. And a careful examination of them usually reveals small (a millimeter or so in diameter) blue- green spots. These spots are packages of symbiotic cyanobacteria (once called “blue-green algae”) fixing nitrogen for the plant.

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  Ecological Aspects of Nitrogen Metabolism in Plants

  • Joe C. Polacco, Christopher D. Todd(Authors)
  • 2011(Publication Date)
  • Wiley

    (Publisher)

  * Nitrogen in our environment has both benefits as well as negative consequences. The primary benefit of nitrogen is the stimulation of plant growth in agriculture for food, feed, and fuel, whereas the negative aspects include almost all environmental impacts. Compared to elements such as carbon, sulfur, or phosphorus, nitrogen contributes to a variety of negative impacts, most interrelated, such as climate change, eutrophication, soil acidification, degraded human health, loss of biodiversity, etc. In 2008 we celebrated the one-hundredth anniversary of the invention of the production of ammonia by Fritz Haber in 1908. Ammonia is the basis for fertilizer production, and Carl Bosch was able to turn that ammonia production into an industrial process (Smil, 2001; Erisman et al., 2008). Bosch and Haber were awarded the Nobel Prize for their achievements. Ammonia is not only the basis for fertilizer, but also for many industrial chemicals, including explosives. So, overall, the Haber-Bosch process was beyond doubt one of the most important inventions of the twentieth century (Erisman et al., 2008). Over the past decades the production of fertilizer has become very energy and economically efficient (Kongshaug, 1998) and on a large scale has increased agricultural productivity. Without fertilizer input, the biosphere would produce 48% less food (Erisman et al., 2008). Therefore, at present, we cannot live without fertilizer. At the same time, industrialization increased the use of fossil fuels. To use the energy from fossil fuels, they are burned, resulting in a large release of oxidized nitrogen (NOx) into the atmosphere. Vehicular traffic, energy use, and industry are the principal sources of oxidized forms of Nr. The dispersion of NOx has affected human health and increased nitrogen deposition in remote areas leading to eutrophication (Erisman and Fowler, 2003).

  This book is dedicated to plant “strategies” to acquire, assimilate, and conserve N. Much emphasis is given to plant interactions with microorganisms (Frankia , rhizobia, mycorrhizae). Biological N-fixation is prominently covered and is an important part of the Nitrogen cycle. However, in order to establish the need for knowledge in the area of biological N fixation (and the N “conduits” that mycorrhizae provide for delivering soil N to plant), we have to address the “big picture” first, providing background on the major components of the Nitrogen cycle on different scales, emphasizing the human contribution to the increased cycling of nitrogen in the biosphere and the resulting impacts on ecosystems and humans. This introductory chapter addresses these issues as a global overview of the human influence on the Nitrogen cycle.

  The Preindustrial Nitrogen cycle

  Nitrogen is an important element—the most abundant constituent of the atmosphere, hydrosphere, as well as the biosphere. It is also one of the essential elements for the growth of plants and animals and has a crucial role in ecology and in the environment. It is useful to look at the reactions of elements in the form of a closed cycle. Such a cycle is often termed a biogeochemical cycle because chemistry, biology, and geology all provide important inputs. Cycling of elements is often governed by kinetics and may involve the input of energy, so that chemical equilibrium states are not attained. The ultimate source of energy for driving energetically uphill reactions is the sun. The earth’s surface receives an average radiation input of 100–300 W/m2 % day, depending on latitude. Some of this is captured by photosynthesis, and is used to produce high-energy content molecules, such as oxygen. Because of the inherently low efficiency of the photosynthetic process and the production of phytomass, energy supply from this source has low power densities and hence high land demands. Recent estimates of the global terrestrial net primary productivity (NPP) average approximately 120 gigaton (Gton) of dry biomass produced annually, and that contains some 1,800 × 1018

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  Mineral Nitrogen In The Plant-Soil System

  • R Haynes(Author)
  • 2012(Publication Date)
  • Academic Press

    (Publisher)

  (1982). The Nitrogen cycles. In The Natural Environment and the Biogeochemical Cycles (O. Hutzinger, ed.), pp. 61-81. Springer-Verlag, Berlin and N e w York. Sôderlund, R., and Svensson, Β. H. (1976). The global Nitrogen cycle. In Nitrogen, Phos-phorus and Sulphur—Global Cycles (Β. H. Svensson and R. Sôderlund, eds.), pp. 23-73. Ecological Bulletins, Stockholm. Staaf, H., and Berg, B. (1981). Plant litter input to soil. In Terrestrial Nitrogen cycles: Processes, Ecosystem Strategies and Management Impacts (F. E. Clark and T. Rosswall, eds.), pp. 147-162. Ecological Bulletins, Stockholm. 50 1. Distribution and Cycling of Ν Steinhart, U. (1973). Input of chemical elements from the atmosphere. A tabular review of literature. Gôttinger Bodenkd. Ber. 29, 93-132. Stevens, P. R., and Walker, T. W. (1970). The chronosequence concept and soil formation. Q. Rev. Biol. 45, 333-350. Stevenson, F. J. (1965). Origin and distribution of nitrogen in soil. In Soil Nitrogen (W. V. Bartholomew and F. E. Clark, eds.), pp. 1-42. Am. Soc. Agron., Madi-son, Wisconsin. Stevenson, F. J. (1982). Humus Chemistry. Genesis, Composition, Reactions. Wiley, N e w York. Stewart, W. D. P. (1980). Some aspects of structure and function in N 2 -fixing cyanobacteria. Annu. Rev. Microbiol. 34, 497-536. Stewart, W. D. P., Rowell, P., and Rai, A. N. (1981). Symbiotic nitrogen fixing cyanobacte-ria. In Nitrogen Fixation (W. D. P. Stewart and J. R. Gallon, eds.), pp. 239-277. Academic Press, N e w York. Swift, M. J., Heal, O. W., and Anderson, J. M. (1979). Decomposition in Terrestrial Ecosystems. Blackwell, Oxford. Syers, J. K., Adams, J. Α., and Walker, T. W. (1970). Accumulation of organic matter in a chronosequence of soils developed on wind-blown sand in New Zealand. J. Soil. Sci. 21, 46-153. Tamm, C. O., Holmen, H., Popovic, B., and Wiklander, G. (1974). Leaching of plant nutrients from soils as a consequence of forestry operations.

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  Structure and Function in Agroecosystem Design and Management

  • Masae Shiyomi, Hiroshi Koizumi, Masae Shiyomi, Hiroshi Koizumi(Authors)
  • 2001(Publication Date)
  • CRC Press

    (Publisher)

  Today, mankind produces nitro-gen fertilizer by fixing atmospheric nitrogen and supplies this to croplands in order to increase production, disturbing the natural Nitrogen cycle. GLOBAL BALANCE The amount of nitrogen in Earth’s Nitrogen cycle is shown in Table 17.1. Such data are continuously being refined, and the numbers will inevitably change as better estimates become available. A great deal of nitrogen exists in the atmosphere. N 2 gas, which exists in the ocean in a dissolved state, abounds. Dissolved or suspended nitrogen in the ocean and organic nitrogen Table 17.1 Estimates of Active Pools in the Global Nitrogen cycle. Million tonnes N 2 Air N 2 3,900,000,000 N 2 O 1,400 Land Plants 15,000 Animals 200 of which is people 10 Soil organic matter 150,000 of which is microbe microbial biomass 6,000 Sea Plants 300 Animals 200 In solution or suspension 1,200,000 of which is NO 3 —N 570,000 of which is NH 4 —N 7,000 Dissolved N 2 22,000,000 Jenkinson, 1990. Nitrogen cycle AND AGRICULTURE 355 in the soil also abound. The nitrogen included in the biomass is very small compared with these quantities. The nitrogen moves between these pools. This circulation is illustrated in Figure 17.2. The nitrogen fixation rate by microorganisms in the terrestrial ecosystem is estimated as 139 Tg/year, an estimation based on Burns and Hardy (1975). This quantity is equivalent to approximately 10 kg/ha/year for each hectare of the Earth’s land surface. The details of the estimation are shown in Table 17.2. Hardy has estimated the fixation in the ocean at 36 Tg/year. Jenkinson (1990) has summarized the rel-evant previous research. It has been estimated that nitrogen fixation quantity in nature is 60 to 260 Tg/year (Jenkinson, 1990). Some nitrogen fixation occurs when there is lightning, but this quantity is much smaller than that fixed by bacteria. Jenkinson has estimated this as 2 to 8 Tg/year. Nitrogen fix-ation also occurs with the high-temperature combustion of fossil fuel.

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  Soil Fertility

  • Boyd Ellis, Henry Foth(Authors)
  • 2018(Publication Date)
  • CRC Press

    (Publisher)

  Figure 6.2  The major segments of the soil Nitrogen cycle consist of fixation, mineralization, nitrification, immobilization, and denitrification. Some nitrogen is also lost in the cycle by volatization and leaching and some ammonium is temporarily unavailable because it is fixed in clay.

  6.1.4   Importance of Biological Nitrogen Fixation

  Nitrogen fixation is both biological and nonbiological. Some nonbiological N fixation is caused by lightning discharges. Other N in the atmosphere originates from burning of fossil fuels and forests and from the emission of magmatic gases. This N is added to soils as nitrate and ammonium in precipitation. Most of the N added naturally to soils is from biological fixation that is symbiotic or non-symbiotic in nature. In all ecological niches, there are N-fixing organisms including bacteria, algae, and actinomycetes. It has been estimated that of the 12.8 kg N/ha (11.4 pounds N/acre) of N naturally added to soils annually, 72% comes from biological N fixation and 28% from the other sources. The other sources are mainly from lightning discharges, burning of fossil fuels and forests, and from the emission of magmatic gases. This N is added to soils as nitrate and ammonium in precipitation.

  6.2 BIOLOGICAL NITROGEN FIXATION

  Considering the large amount of N added to soils by biological fixation and the importance of N in plant growth, biological N fixation can be considered one of the most important processes in nature. In a way, it is similar to photosynthesis. There is a ubiquitous need for N in nature and many different kinds of microorganisms that fix N. The great diversity of fixation sites and organisms is illustrated by a flooded rice field (paddy), as shown in Figure 6.3 .

  Figure 6.3

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  Molecular Geomicrobiology

  • Jillian F. Banfield, Javiera Cervini-Silva, Kenneth Nealson(Authors)
  • 2018(Publication Date)
  • De Gruyter

    (Publisher)

  Reviews in Mineralogy & Geochemistry Vol. 59, pp. 211-231,2005 Copyright © Mineralogical Society of America 9 The Evolution of Biological Carbon and Nitrogen Cycling—a Genomic Perspective Jason Raymond Microbial Systems Division Biosciences Directorate Lawrence Livermore National Laboratory Livermore, California, 94550, U.S.A. jason. raymond@ llnl. gov INTRODUCTION Carbon and nitrogen are essential to all living organisms, owing to their abundance and remarkable characteristics when participating in chemical bonds. Their essentiality dates back to the very origin of life, where current theories hypothesize either a prebiotic abundance of organic compounds rich in carbon and nitrogen, or an ability to assimilate them inorganically through abiotic reactions that might have been catalyzed on ancient mineral surfaces. This chapter details the core reactions essential to the assimilation of these elements in biologically useful forms—the so-called fixation of carbon and nitrogen—focusing on recent literature and insights from comparative genomics and phylogenetics. Though considerable debate continues on the antiquity of these pathways, especially whether or not they might have been present in the last common ancestor (LCA) of modern organisms, it is clear that carbon and nitrogen fixation pathways were of crucial importance to the primitive ancestors of extant life. Furthermore, the biological assimilation of inorganic carbon (autotrophy) and atmospheric nitrogen (diazotrophy) represent pivotal juxtapositions of biological and geological cycles. It is thought that atmospheric C0 2 concentrations have decreased substantially since the proposed origin of life some 3.8 billion years ago, due in large part to either primary (fixation) or secondary (e.g., weathering) influence by biota (Hayes 1994; Rye et al. 1995; Des Marais 1997; Lowe and Tice 2004).

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  Advances in Biology and Ecology of Nitrogen Fixation

  • Takuji Ohyama(Author)
  • 2014(Publication Date)
  • IntechOpen

    (Publisher)

  Section 1 Biology of Nitrogen Fixation Chapter 1 Nitrogen Fixation Outside and Inside Plant Tissues C.P. Chanway, R. Anand and H. Yang Additional information is available at the end of the chapter http://dx.doi.org/10.5772/57532 1. Introduction Nitrogen is one of the most important elements in biological systems, comprising the main building blocks of nucleic acids, enzymes and proteins among its multiple functions. In nature, it exists primarily in the gaseous form and constitutes approximately 78% of the atmosphere. Despite its abundance, nitrogen (N) is one of the most growth-limiting nutrients in terrestrial and aquatic ecosystems (Dalton & Krammer, 2006) because its gaseous form is inert and unusable by most living organisms except for nitrogen fixing microorgansisms. For it to become biologically available, atmospheric nitrogen must be transformed or “fixed” from its inert gaseous form (N 2 ) to ammonia (NH 3 ), which can then be assimilated into a variety of important biochemicals. This transformation, which requires a large amount of energy to break apart the triple-bonded N atoms that comprise gaseous N 2 , is called ‘nitrogen fixation’ (NF). Nitrogen is fixed naturally through energy-releasing abiotic processes such as lightening, forest fires and volcanic activity. These processes produce oxides of N in the atmosphere that subsequently dissolve in rain and descend to the ground as NH 3 molecules. Approximately 12% of annual global NF is fixed in this way (Bezdicek & Kennedy, 1998). Fertilizer production using high temperatures and pressures in the Haber-Bosch process occurs widely and accounts for approximately 20% of annual global NF (Bezdicek & Kennedy, 1998). However, the process is fossil-fuel intensive and consumes 3-5% of the world’s natural gas annually (Myrold & Bottomley, 2007).

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  The Atmospheric Environment

  Effects of Human Activity

  • Michael B. Mcelroy(Author)
  • 2021(Publication Date)
  • Princeton University Press

    (Publisher)

  The summaries in Table 12.1 and Figure 12.1 are nonetheless useful. They provide a con- venient framework, allowing us to focus on the large-scale, overall features of the global Nitrogen cycle. In particular, they afford a useful starting point to assess the significance of specific disturbances associated with human activity, as may be illustrated by considering the case of fixation. The fixation of nitrogen under natural conditions in ter- restrial systems is accomplished to a large extent by bacteria acting in symbiotic association with selected plants. Particularly important is the relationship between bacteria of the genus Rhizobium and plants of the family Leguminosia. Neither the bacterium nor the plant acting alone has the ca- pacity to fix nitrogen. Acting together, however, they are able to accomplish this formidable feat with remarkable ease. The relationship is said to be symbiotic. Energy equiv- alent to 226 kcal mol –1 is required to rupture the NN triple bond in N 2 . A portion of this energy may be recovered as ni- trogen is converted to compounds such as NH 4 + or NO 3 – . Fixation of nitrogen in an industrial chemical plant requires a major allocation of economic resources. It proceeds at tem- peratures in excess of 500°C, consuming large quantities of fossil fuels. The rhizobium-legume combination accom- plishes a similar feat using sunlight as an energy source and operating under natural conditions without the need for ex- traneous inputs of either material or energy. A healthy legu- minous crop can be remarkably effective in fixing nitrogen. Yields as large as 120 kg N per hectare per year are common in temperate regions, whereas yields as much as 3 times higher have been achieved in well-managed pastures. Alfalfas, clovers, and lupines are particularly effective as agents for symbiotic fixation of nitrogen. Yields from peas, beans, and peanuts are relatively more modest.

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  Soil Microbial Associations

  Control of Structures and Functions

  • V. Vancura, F. Kunc(Authors)
  • 2012(Publication Date)
  • Elsevier Science

    (Publisher)

  If the system is in an equilibrium state, it is possible to write: A/k = 7V S , w h e re N s is the content of Í under the equilibrium state of the plant-soil system . J E N K I N S ON ( 1 9 6 6) calls attention to the fact t h at the reality is highly simplified in this model, which assumes t h at ( 1) the y e a r ly input of biomass , A, is a steady process , (2) the rate of organic matter decomposition is independen t of the amount of organic matter added , a nd (3) all component s of the organic matter decompose at the s a me rate. P a rt of the produced ammonium c an be i m m o b i l i z ed in the biotic c o n-stituents of the ecosystem a nd retransformed into organic nitrogen; p a rt c an be b o u nd in c l ay minerals or in soil matter; p a rt c an volatilize as ammonia into the air; p a rt c an be b o u nd in the sorption complex of soil a nd a p a rt c an be nitrified. T h e re is v e ry littl e i n f o r m a t i on on the extent a nd proportions of ammonium transfer or transformation . A c c o r d i ng to R E U SS ( 1 9 8 1 ), only 6 kg nitrogen in the form of ammonium a nd nitrates enter the soil from cattle excrement s in the grazed grasslands at Pawnee , while 75 kg p er ha p er y inorganic nitrogen a re a v a i l a b le through the mineralization of soil organic matter. Nitrification is a biologically conditioned process responsibl e for the o x i d a-tion of ammonium to nitrites a nd nitrates. The recently published papers a nd review articles on nitrification ( F O C H T a nd VERSTRAETE , 1 9 7 7; BECK, 1 9 7 9; VERSTRAETE , 1 9 8 1) s h ow t h at the ecology of nitrification is rather complicated a nd e v en confused , a nd t h at it comprises a whole complex of processe s mediated by different groups of microorganisms , f u n c t i o n i ng under different conditions. Heterotrophi c nitrification c an be performed by a number of soil organisms producing nitrites a nd nitrates by fermenting a ny energy source in the presence of ammonium nitrogen.

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